D i c t i o n a r y
of
Minings Mineral^ and
R e l a t e d T e r m s
C o m p i l e d b y
the
Publ i shed
Society for Mining, Metal lurgy, and Explorat ion, Inc .
 
A s th e N a t i o n ' s p r i n c i p a l c o n s e r v a t i o n a g e n c y , t h e D e p a r t m e n t o f t h e I n t e -
r i o r h a s r e s p o n s i b i l i t y f o r m o s t o f o u r n a t i o n a l l y o w n e d p u b l i c l a n d s a n d n a t -
u r a l r e s o u r c e s . T h i s i n c l u d e s f o s t e r i n g t h e s o u n d u s e o f o u r l a n d a n d w a t e r
r e s o u r c e s ; p r o t e c t i n g o u r f i s h , w i l d l i f e , a n d b i o l o g i c a l d i v e r s i t y ; p r e s e r v i n g
t h e e n v i r o n m e n t a l a n d c u l t u r a l v a l u e s o f o u r n a t i o n a l p a r k s a n d h i s t o r i c a l
p l a c e s ; a n d p r o v i d i n g f o r t h e e n j o y m e n t o f l if e t h r o u g h o u t d o o r r e c r e a t i o n .
T h e D e p a r t m e n t a s s e s s e s o u r e n e r g y a n d m i n e r a l r e s o u r c e s a n d w o r k s t o a s -
s u r e t h a t t h e i r d e v e l o p m e n t i s i n t h e b e s t i n t e r e s t s o f a l l o u r p e o p l e b y e n -
c o u r a g i n g s t e w a r d s h i p a n d c i t i z e n p a r t i c i p a t i o n in t h e i r c a r e . T h e
D e p a r t m e n t a l s o h a s a m a j o r r e s p o n s i b i l it y f or A m e r i c a n I n d i a n r e s e r v a t i o n
c o m m u n i t i e s a n d f o r p e o p l e w h o l i v e i n i s l a n d t e r r i t o r ie s u n d e r U . S . a d m i n i s -
t r a t i o n .
U . S . D e p a r t m e n t o f t h e I n t e r i o r
B r u c e B a b b i t t ,  Secretary
U . S . B u r e a u o f M i n e s
R h e a L y d i a G r a h a m , D i r e c t o r
C o m p o s e d in P a l i n t i n o u s i n g V e n t u r a P u b l i s h e r 3 . 0 .
P r i n t e d o f f s e t o n D o m t a r W i n d s o r , a n a c i d -f r e e p a p e r , b y B r a u n - B r u m f i e l d ,
I n c .
B o u n d i n I n d u s t r i a l C o a t i n g s G r o u p , I n c . A r r e s t o x .
C o p y r i g h t 1 9 9 7 b y t h e A m e r i c a n G e o l o g i c a l I n s t i t u t e , 4 2 2 0 K i n g S t r e e t, A l e x -
a n d r i a , V i r g i n i a 2 2 3 0 2 U S A . P r i n t e d a n a b o u n d in t h e U n i t e d S t a t e s o f A m e r -
i c a . A l l r i g h t s r e s e r v e d .
 
F o r e w o r d
The need for a revised mining dict ionary is obvious wh en one cons iders the tech-
nical advances , environmen tal regulat ions , and other change s that ha ve occurred
since the Bureau's previous mining dict ionaries were publ ished. The Bureau had pi-
oneered efforts in this field, beginning in 1918 with Fay's
  Glossary of the Mining arid
Minerals Industry,
 Dictiottary of Mining,
Mineral, mid Related Term s.
To develop a mo dern m ining dict ionary, the U.S . Bureau of Min es ini t iated a col -
laborat ive project with the American G eological Inst itute . The Bu rea u's s taf f , the
Inst i tute 's s taf f and members , and many minerals experts throughout the Nation con-
tributed their expertise to the work. In the 5-year project 's f inal phase, more than 100
Bureau perso nnel we re involved in the technical review an d publ icat ion prod uct ion
process . I wo uld l ike to thank al l those who assis ted in produ cing this new min ing
dict ionary, especial ly the Dict ionary Revis ion Group members and the Bureau's engi-
neers, scientists, and editors.
The C D-R OM version of the Dict ionary Revis ion is one of the last publ icat ions of
the U.S . Bureau of M ines . Although the agency is c losing, the Bure au 's mine rals in-
formation functions will transfer to the U.S. Geological Survey.
I bel ieve this new dict ionary wil l benef i t the Nations by con tinuing one o f the Bu-
reau of Mines importan t missions, that of providing information on m inerals , the
building blocks of our society, and mining, one of the world's oldest industries.
Rhea Lydia Graham
Preface to the pr int edi t ion
This edit ion of the Dictionary of Mining, Mineral, and Related T erms,  publ ished by
the American Geological Inst i tute in cooperat ion with the Society for Mining, Metal -
lurgy , and E xplora t ion, Inc . , i s the print vers ion of a CD -RO M, released by the U.S .
Bu reau of Min es in ear ly 1996. Based on the f i rst edit ion publ ished by the Bureau in
1968 (Paul W. Thrush, editor) , the compilat ion and content review was coordinated
by the American Geological Inst i tute (USBM Contract Number J0101017) . This publ i -
cat ion represents the dedicat ion and efforts of many individuals , including Bureau
personnel , members of the mining and minerals community, and the staf f of the
Am er ican Geo log ica l Ins t i tu te .
P r e f a c e
Technological developments and environmental laws and regulat ions that af fect
mining have prol i ferated during the past 25 years . Concurrent ly , the need for a mod-
ern min ing d ic t ionary has grown — one that incorporates not only standard m ining-
related te rm s but a lso terms in periph eral areas , such as the environmen t , pol lut ion,
automation, heal th and safety . The new edit ion of the Dict ionary of Mining and Min-
eral Relate d Te rm s is the culmina t ion of a 5-year effort between the U.S . Bureau of
mines and the Amer ican Geolog ica l Ins t i tu te (USBM CONTRACT NUMBER
J010 101 7) that wil l serve the needs o f those engag ed in minerals-related act ivi ties . I t
is organiz ed to a id the user in app reciat ing the essent ial role that minerals and pro d-
ucts play in our quality of l ife.
The Bureau's development of mining dict ionaries dates back to Albert Fay's
  Glos-
sary of the Mining and Mineral Industry,
  wh ich f irs t appea red in Dece mb er 1918. That
glossary contained about 18 ,000 terms. In 1968, the Bureau publ ished
  A Dictionary of
Mining, Mineral,and Related Terms,  edited by Paul W . Thrush, with about 55 ,000
terms. The 1968 dict ionary contained many new mining terms and terms from such
related areas as metal lurgy, ceramics , and glassmaking. That edit ion was as complete
as possible with re gard to technical and regional terms, histor ical terms, foreign
terms that at ta ined general usage in the United States , and terminology from the en-
t ire Eng l ish-spe akin g w orld. For the past three decades that work has s tood as the de-
f ini t ive authori ty on mineral -re lated terms.
The 1995 ed it ion ref lects a departu re from the previous one in scope and in for-
m at . This ed it ion, containing som e 28,500 term s, is not meant to exhaust ive in its cov-
erage . It focusses on minin g-related terms and excludes such related categories as
ceramics , g lass , metal lurgy, petroleum, and other special ized disc ipl ines . Geological
terms which relate to mining are included, as are minerals which have a commercial
value or which are associated with such minerals . Many chemicals and materials that
are not usual ly connected with mining or minerals processing do not appear , nor di
the chemical e lements unless they are c lass i f ied as minerals . Abbreviat ions and acro-
nyms have largely been excluded, because they usual ly are explained and def ined
within the context of an individual report . The front mater ial ,m however , includes a
l ist of abbreviat io ns us ed in the def ini t ions . N ew terms on ma rine mining, leaching,
and automation appear in this edit ion as do a plethora of pol lut ion and environmen-
tal terms, m an y of which h ave a legal def ini t ion base d on law or regulation.
The task of deciding which terms should be deleted from this edit ion, how to en-
sure the col lect ion of new terms s ince 1968, and how to cul l terms for inclusion w as
 
egory w as review ed by at least one subject special is t . The review ers judged wh ich
terms sho uld be retained or deleted, and they revised def ini t ions as necessary and
defined new terms. Final judg m ent of the inclusion of exist ing terms or the addit ion
of new ones was left to the collective discretion of a panel of experts called the Dictio-
nary Review Group. This group also examined the Society of Mining Engineer 's
  Min-
ing Engineering Hand book,
  1993 edit ion, to ensure that the mo st mo dern terms and
their def ini t ions would be considered.
A c k n o w l e d g m e n t s
Special is ts in ma ny asp ects of mining ha ve voluntee red their help in br ingin g the
wide ly used
  up to date , by reviewing
defini t ions , adding new terms, recommending correct ions , and c i t ing references ,
Hundreds of special is ts contr ibuted to the new edit ion. The mining and minerals
community owes special grat i tude to the members of the Dict ionary Revis ion Group:
Robert L . Bates ; V.A. Cammarota ; M. El izabeth Clare ; John DeYoung, Jr . ; James F .
Don ahue ; C har les D . Hoyt ; T im O 'Nei l ; Eugene Pa lowi tch ; John W . Padan ; Glor ia
Ru ggiero ; A1 Schreck; Ro bert Tuchm an; and Dirk Van Zyl .
vi i
 
A B B R E V I A T I O N S
Abbreviations of certain terms, place names,
and units of measu re are used in the definitions as
follows:
esp - espec ia l ly
et al . - and others
etc. - and so forth
E t y m o l . - e t y m o l o g y
i.e. - that is
Berks - Berkshire , England.
Bol - Bolivia.
Braz - Brazil .
Br is t - Br i s to l coa l f ie ld , Eng land.
C a n - D o m i n i o n o f C a n a d a .
C e n t . A m . - C e n t r a l A m e r i c a .
C h e s - C h e s h i r e , E n g l a n d .
Clev - Cleveland i ron dis t r i c t , England.
Colom - Uni ted S ta tes o f Colombia .
C o r n - C o r n w a l l , E n g l a n d .
C u m b - C u m b e r l a n d c o a l f i e l d , E n g l a n d .
Derb - Derb yshir e coa l f ie ld , Eng land.
Dev - Devon shire , Englan d.
E. Ind - East Indies.
Eng - England.
Fores t o f Dean - Fores t o f Dean coal f ie ld , En gland .
Fr - French.
Gr. Brit - Great Britain.
Hid - Hidalgo , Mex.
H i n d - H i n d u s t a n .
Ire - Ireland.
It - Italian.
Leic - Le ices tershire , England.
M e x - M e y a c o .
Mid - Mid land coal f ie ld , En gland .
Newc - Newcast le coa l f ie ld , England.
N.S .W. - New South Wales , Austra l ia .
N.Z. - New Zeala nd.
N. o f Eng. - North of England.
N. S ta f f - No rth S ta f ford shire coa l f ie ld , E ngland .
N o r t h u m b - N o r t h u m b e r l a n d c o a l f ie l d , E n g l a n d .
N. Wales - North Wales .
Pac - Pac i f i c Coast , U .S .A.
Pat - Patagonia , South America .
Por t - Por tu guese (most ly in B raz i l ) .
Prov - Provinc ia l , U .S . , unless o therwise , sp ec i f .
Pr - Prussian.
PI. - plural
specif . - specif ically
S . Am - South America .
S . S ta f f - South S ta f fordsh ire , E ngla nd.
S . Wales - South W ales , Great B r i ta in .
S o m - S o m e r s e t , E n g l a n d .
Sp - Spanish or ig in but not necess . used in Spain .
Sp Am - Spanish America .
S ta f f - S ta f fordshire , Englan d.
Suf f - Suf fo lk , En gland .
Sw - Swedish .
Tran s - Transvaal , Repu bl ic o f Sou th A fr ica .
U.K . - Un i ted Kingd om of Great Br i ta in and N. I re .
U.S . - Uni ted S ta tes o f Am erica .
U.S .S .R . - Union of Sovie t Soc ia l i s t Rep ubl ics .
Venez - Venezuela .
W . Afr - We st Afr ica .
W a r - W a r w i c k s h i r e , E n g l a n d .
W is - Wisco ns in , U .S .A.
York - Yorkshire , England.
AK - Alaska
C O - C o l o r a d o
CT - Connect icut
IN - Indiana
IA - Iowa
KS - Kansas
K Y - K e n t u c k y
LA - Louis iana
M D - M a r y l a n d
MA - Massachuset ts
MI - Michigan
M N - M i n n e s o t a
MS - Miss iss ippi
C a n a d a
AB - Alber ta
LB - Labrador
MB - Mani toba
N B - N e w B r u n s w i c k
N F - N e w f o u n d l a n d
N T - Northw est Terr i tor ies
N H - N e w H a m p s h i r e
N J - N e w J e r s e y
N M - N e w M e x i c o
N Y - N e w Y o r k
N C - N o r t h C a r o l i n a
N D - N o r t h D a k o t a
O H - O h i o
O K - O k l a h o m a
O R - O r e g o n
P A - P e n n s y l v a n i a
R I - R h o d e I s l a n d
S C - S o u t h C a r o l i n a
S D - S o u t h D a k o t a
T N - T e n n e s s e e
T X - T e x a s
U T - U t a h
V T - V e r m o n t
V A - V i r g i n i a
W A - W a s h i n g t o n
W V - W e s t V i r g i n i a
W I - W i s c o n s i n
W Y - W y o m i n g
C Z - C a n a l Z o n e
D C - D i s t r i c t o f C o l u m b i a
G U - G u a m
P R - P u e r t o R i c o
VI - Virg in I s lands
O N - O n t a r i o
P E - P r i n c e E d w a r d I s l a n d
P Q - Q u e b e c
S K - S a s k a t c h e w a n
U T - Y u k o n T e r r i t o r y
v i i i
Units o f Measure
Ab brev ia t io ns for Com poun d Uni t s
T w o t y p e s o f c o m p o u n d u n i t a b b r e v i a t i o n s a r e
c o m m o n .
1 . I n t h e m e t r i c s y s t e m , m a n y u n i t s c o m p r i s e a
b a s i c u n i t , s u c h a s m ( m e t e r ) m o d i f i e d b y a p r e f i x
t h a t a c t s a s a p o w e r o f t e n m u l t i p l i e r . T h u s c m i s
a c e n t i m e t e r , o n e - h u n d r e t h o f a m e t e r o r 1 0
m e t e r .
S e v e r a l c o m p o u n d m e t r i c u n i t s a r e w i d e l y u s e d
i n t h i s v o l u m e :
m u m - m i c r o m e t e r ( s ) ; c m - c e n t i m e t e r ( s ) ; K j -
k i l o j o u l e ( s ) ; k m - k i l o m e t e r ( s ) ; K p a - k i l o p a s c a l ( s ) ;
M J - m e g a j o u l e ( s ) ; M l - m i l l i l it e r ( s ) ; m m - m i l l i m e -
t e r s ) ; M p a - m e g a p a s c a l ( s ) .
2 . C o m p l e x u n i t s a r e d e v e l o p e d b y m u l t i p l y i n g
( ° ) o r d i v i d i n g ( / ) u n i t s . T h e m e t r i c u n i t s f o r m o -
m e n t u m , f o r e x a m p l e , a r e k g m / s , w h i c h is r e a d
N e w t o n m e t e r s p e r s e c o n d .
Abbreviat ions for Units o f Meast i re
degrees C - degrees Cels ius
degrees F - degrees Fahren-
AU - as t ronomica l uni t
bbl - barre l ( s )
flow)
day (gas f low)
yea r (gas f low)
Btu - Brit ish thermal unit(s)
Bunit - bi l l ion units(s)
c - cycle
pref ix only
cmil - c ircular mil
c p - c a n d l e p o w e r
cpm - count (s ) per minute
cps - cont (s ) per second
d - day(s )
dyn - dyne(s )
ft - foot/feet
f t - squa re foot/feet
f t ° l b f - f o o t p o u n d ( s ) ( f o r c e )
g - gram(s)
G - giga (one bil l ion); prefix
only
H.E . - h igh exp los ive(s )
h p - h o r s e p o w e r
hp h - hors epow er hour
Hz - cycle(s) per second
in - inch(es)
1 - jou le(s)
fix only
- liter(s)
L - lamb ert (s )
lbt« f t - pound(s ) force foot
It - long ton(s)
pref ix only
Mcf - thousand cubic fee t
(gas f low)
per day
mi - mile(s)
Mmbl - mi l l ion barre ls
Mmcf - mi l l ion cubic fee t
(gas f low)
per day (gas f low)
Mmcfy - mi l l ion cubic fee t
per year (gas f low)
mol - mole(s )
m o l w t - m o l e w e i g h t
mol % - mole percent
mph - mi le (s ) per hour
M x - m a x w e l l ( s )
n - nano (one-b i l l ionth) ; pre-
f ix only
N - N e w t o n ( s )
nmi - naut ica l mi le (s )
Oe - oers ted(s )
o h m » c m i l / f t - o h m c i r c u l a r
mi l per foot
o z - o u n c e ( s )
p - p ico (one- t r i l l ionth) ; pre-
f ix only
P - poise (s )
ppb - par t (s ) per b i l l ion
ppm - par t (s ) per mi l l ion
ps i - pound(s ) ( force) per
s q u a r e i n c h
psia - pound(s ) force per
ps ig - pound(s ) force per
s q u a r e i n c h , g a u g e
r - revolut ion(s )
R - rontgen(s )
rad - radian(s )
r p m - r e v o l u t i o n s p e r m i n -
ute
sr - s teradian(s )
S t - s toke(s )
3
  - s t a n d a r d c u b i c
f o o t / f e e t
t - metr ic ton(s )
w o r k e r h o u r
t/w-d - metr ic ton(s ) per
w o r k e r d a y
T - t e s l a ( s )
t r oz - t roy ounce(s )
unit
1
u n i t
s q u a r e d )
uni t - cub ic uni t
W - wat t ( s )
wt % - wt pet , weight per -
cent
yr - year (s )
L e g i s l a t i o n R e l a t e d t o M i n i n g a n d
M i n e r a l s
Clean Air Act o f 1970
C l e a n A i r a n d W a t e r A c t A m e n d m e n t s o f 1 9 7 7
C o m p r e h e n s i v e E n v . R e s p o n s e C o m p . , & L i a b i l i t y A c t
( C E R C L A )
D e e p S e a b e d H a r d M i n e r a l R e s o u r c e s A c t o f 1 9 8 0
E n d a n g e r e d S p e c i e s A c t o f 1 9 7 3
F e d e r a l L a n d P o l i c y & M a n a g e m e n t A c t o f 1 9 7 6
Federa l Mine Safe ty and Heal th Act o f 1977
F e d e r a l W a t e r P o l l u t i o n C o n t r o l A c t o f 1 9 7 2
Law of the Sea Treaty
M i n e r a l L e a s i n g A c t f o r A c q u i r e d L a n d s
M i n i n g L a w o f 1 8 7 2
N a t i o n a l E n v i r o n m e n t a l P o l i c y A c t o f 1 9 6 9 ( N E P A )
O u t e r C o n t i n e n t a l S h e l f L a n d s A c t o f 1 9 5 3
R e s o u r c e C o n s e r v a t i o n & R e c o v e r y A c t o f 1 9 7 6 ( R C R A )
S u b m e r g e d L a n d s A c t o f 1 9 5 3
S u p e r f u n d A m e n d m e n t s & R e a u t h o r i z a t i o n A c t o f 1 9 8 6
S u r f a c e M i n i n g C o n t r o l & R e c l a m a t i o n A c t o f 1 9 7 7
( S M C R A )
T o x i c S u b s t a n c e s C o n t r o l A c t o f 1 9 7 6
U r a n i u m M i l l T a i l i n g s R a d i a t i o n C o n t r o l A c t , 1 9 7 8
W a t e r Q u a l i t y A c t o f 1 9 8 7
O r g a n i z a t i o n s a n d A c r o n y m s
A i r P o l l u t i o n C o n t r o l A s s o c i a t i o n ( A P C A )
A m e r i c a n A s s o c ia t i o n of P e t r o l e u m G e o l o g i s t s ( A A P G )
A m e r i c a n C h e m i c a l S o c i e t y ( A C S )
i x
 
A m e r i c a n C o n f e r e n c e o f G o v e r n m e n t a l I n d u s t r i a l H y g i e n -
i s t s ( A C G I H )
A m e r i c a n E l e c t r o c h e m i c a l S o c i e t y ( A E S )
A m e r i c a n E l e c t r o m e c h a n i c a l S o c i e t y ( A E S )
A m e r i c a n E l e c t r o p l a t e r s ' S o c i e t y ( A E S )
A m e r i c a n F o u n d r y m e n ' s A s s o c i a t i o n ( A F A )
A m e r i c a n F o u n d r y m e n ' s S o c ie t y ( A F S )
A m e r i c a n G a s A s s o c i a t i o n ( A G A )
A m e r i c a n G e o l o g i c a l I n s t i t u t e ( A G I )
A m e r i c a n H e r i t a g e C e n t e r ( A H C )
A m e r i c a n I n d u s t r i a l H y g i e n e A s s o c i a t i o n ( A I H A )
A m e r i c a n I n s t it u t e o f C h e m i c a l E n g i n e e r s ( A I C h E )
A m e r i c a n I n s t i t u t e o f M i n i n g , M e t a l l u r g i c a l , a n d P e t r o -
l e u m E n g i n e e r s , I n c . ( A I M E )
American I ron and Stee l Ins t i tute (AISI )
A m e r i c a n N a t i o n a l S t a n d a r d s I n s t i t u t e ( A N S I ) ( U . S . r e p .
to ISO)
A m e r i c a n P e t r o l e u m I n s t i t u t e ( A P I )
A m e r i c a n P u b l i c H e a l t h A s s o c i a t i o n ( A P H A )
A m e r i c a n S o c i e ty f o r M e t a l s ( A S M )
A m e r i c a n S o c i e t y f o r T e s t i n g a n d M a t e r i a l s ( A S T M )
A m e r i c a n S o c i e t y o f C i v i l E n g i n e e r s ( A S C E )
A m e r i c a n S o c i e t y o f M e c h a n i c a l E n g i n e e r s ( A S M E )
A m e r i c a n S o c i e t y o f S a f e t y E n g i n e e r s ( A S S E )
A s s o c i a t i o n o f I r o n O r e E x p o r t i n g C o u n t r i e s ( A I O E C )
B i t u m i n o u s C o a l I n s t i tu t e ( B C I )
B i t u m i n o u s C o a l O p e r a t o r s ' A s s o c i a t i o n ( B C O A )
C a n a d a C e n t r e fo r M i n e r a l a n d E n e r g y T e c h n o l o g y ( C A N -
M E T )
C a n a d a I n s t i tu t e o f M i n i n g a n d M e t a l l u r g y ( C I M )
C e n t r a l S e l l i n g O r g a n i z a t i o n ( C S O )
C o m m i s s i o n o f t h e E u r o p e a n C o m m u n i t i e s ( C E C )
C o m m o n w e a l t h S c i e n t i f i c a n d I n d u s t r i a l R e s e a r c h O r g a n i -
z a t i o n ( C S I R O )
C o n s e i l I n t e r g o u v e r n e m e n t a l d e s P a y s E x p o r t a t e u r s d e
C u i v r e ( C I P E C )
C o o r d i n a t i n g R e s e a r c h C o u n c i l ( C R C )
Co unc i l for Sc ient i f i c and Industr ia l Resea rch (CS IR)
C o u n c i l o n E n v i r o n m e n t a l Q u a l i t y ( C E Q )
E n v i r o n m e n t a l P r o t e c t i o n A g e n c y ( E P A )
E R O S D a t a C e n t e r
E u r o p e a n C o a l a n d S t e e l C o m m u n i t y ( E C S C )
E u r o p e a n C o m m u n i t y ( E C )
E u r o p e a n F r e e T r a d e A s s o c i a t i o n ( E F T A )
F e d e r a l E m e r g e n c y M a n a g e m e n t A d m i n i s t r a ti o n ( F E M A )
G e n e r a l S e r v i c e s A d m i n i s t r a t i o n ( G S A )
G e o l o g i c a l S o c i e t y o f A m e r i c a ( G S A )
G e o R e f I n f o r m a t i o n S e r v i c e s
G e o s c i e n c e I n f o r m a t i o n S o c i e t y ( G I S )
I l l inois Ins t i tute o f Technology Research Ins t i tute ( I ITRI)
I n d e p e n d e n t P e t r o l e u m A s s o c i a t i o n o f A m e r i c a ( I P A A )
I n s t i t u t N a t i o n a l d e l ' E n v i r o n n e m e n t I n d u s t r i e l e t d e s R i s -
q u e s ( I N E R I S )
Ins t i tute o f E lec t r ica l and Elec t ronics Engineers ( IEEE)
I n s t i tu t e o f M a k e r s o f E x p l o s i v e s ( I M E )
I n s t i tu t e o f R a d i o E n g i n e e r s ( I R E )
I n s t i tu t i o n o f M i n i n g a n d M e t a l l u r g y ( I M M )
I n s t r u m e n t S o c i e t y o f A m e r i c a ( I S A )
I n t e r g o v e r n m e n t a l P a n e l o n C l i m a t e C h a n g e ( I P C C )
I n t e r n a t i o n a l C o p p e r S t u d y G r o u p
Internat ional Energy Agency ( IEA)
Internat ional Labor Organizat ion ( ILO)
Internat ional Lead and Zinc S tudy Group
Internat ional Nicke l S tudy Group
Internat ional Organizat ion for S tandardizat ion ( ISO)
Internat ional T in Counci l ( ITC) (defunct )
Internat ional Union of Pure and Appl ied Chemistry
( I U P A C )
Internat ional Union of Pure and Appl ied Phys ics ( IUPAP)
J o i n t A r m y - N a v y - A i r F o r c e 0 A N A F )
L a w r e n c e L i v e r m o r e L a b o r a t o r i e s ( L L L )
M a n u f a c t u r i n g C h e m i s t s A s s o c ia t i o n ( M C A )
Massachuset ts Ins t i tute o f Technology (MIT)
M i n e S a f e t y a n d H e a l th A d m i n i s t r a ti o n ( M S H A )
M i n e r a l s M a n a g e m e n t S e r v ic e ( M M S )
Nat ional Aca dem y of Sc iences (NAS)
Nat ional Independent Coal Operators Assoc ia t ion
( N I C O A )
Nat ional Ins t i tute for Occupat ional Safe ty and Heal th
( N I O S H )
Nat ional Ins t i tute o f Heal th (NIH)
Nat ional Ins t i tute o f S tandards and Technology (NIST)
Nat ional Labor Rela t ions Board (NLRB)
Nat ional Mine Rescue Assoc ia t ion
Nat ional Petro leum Assoc ia t ion (NPA)
Nat ional Petro leum Ref iners Assoc ia t ion (NPRA)
Nat ional Research Counci l (NRC)
Nat ional Sc ience Foundat ion (NSF)
Nat ional S tone Assoc ia t ion (NSA)
Nat ional Technica l Informat ion Service (NTIS)
Northwest Mining Assoc ia t ion (NSA)
N u c l e a r R e g u l a t o r y C o m m i s s i o n ( N R C )
O c c u p a t i o n a l S a f e t y a n d H e a lt h A d m i n i s t r at i o n ( O S H A )
O c c u p a t i o n a l S a f e t y a n d H e a l t h R e v ie w C o m m i s s i o n
( O S H R C )
Off ice o f Sc ience and Technology Pol icy (OSTP)
Off ice o f Surface Mining Rec lamat ion and Enforcement
( O S M )
O f f i c e o f T e c h n o l o g y A s s e s s m e n t ( O T A )
Organizat ion of Arab Petro leum Export ing Countr ies
( O A P E C )
O r g a n i z a t i o n o f P e t r o l e u m E x p o r t in g C o u n t r i e s ( O P E C )
Soc ie ty for Mining , Meta l lurgy , and Explorat ion , Inc .
( S M E )
Soc ie ty of Automot ive Engineers (SAE)
Soc ie ty of Explorat ion Geophysic i s ts (SEG)
Standard Industr ia l Class i f i ca t ion (S IC)
T e n n e s s e e V a l l e y A u t h o r i t y ( T V A )
The Minera ls , Meta ls , and Mater ia ls Soc ie ty (TMS)
U.S . In ternat ional Trade Commiss ion Divis ion of Minera ls
and Meta ls
U n i t e d M i n e W o r k e r s o f A m e r i c a ( U M W A )
U n i t e d N a t i o n s C o n f e r e n c e o n T r ad e a n d D e v e l o p m e n t
( U N C T D )
Uni ted S ta tes Bureau of Land Management
Uni ted Sta tes Bureau of Mines (USBM)
United Sta tes Geologica l Survey (USGS)
U n i t e d S t e e l w o r k e r s o f A m e r i c a
I
x
 
a  (a) S ym bol in structura l petr ology for the direction of tectonic trans-
port, similar to the direction in which cards might slide over one
another. Striations in a slickensided su rface are parallel to direction  a.
(AG I, 1987) (b) A cry stallogra phic axis: In the isometric system each
axis is designated a; in hexagonal, tetragonal, and trigonal systems the
nonunique axes are a ;  in the orthorhombic system  a  is always shorter
than  b  w i t h  c  either the longest or the shortest axis; in the monoclinic
and tr ic l in ic systems  a  may be determined by one of several conven-
tions.
aa A Ha wai ian term for lava consist ing of a rough assemblage of
clinkerlike scoriace ous masse s. It is contrasted with pahoe hoe used to
desig nate the smo othe r flow s. Pron. ah-ah. (Fay, 1920; Hess)
n axis (a) On e of the three crysta llograp hic axes used as reference in
crystal description . It is oriented horizon tally, front to back, (b) On e
of three reference axes used in describing a rock fabric possessing
monocl inic symm etry , such as progress ive s imple shear . The a axis is
the direction of tectonic transport, i .e. , the direction of shear. Syn:  a
direction.
 b axis; c axis.:
a b a n d o n e d m i n e  abandoned workings.
aban don ed work ing s Excavat ions , e i ther caved or sealed, that are
deserted and in which further mining is not intended and open w ork-
ings that are not ventilated and inspected regularly. Syn:  abandoned
mine.  (Federal Min e Safety , 1977)
aban donm ent Aban donm ent of a mining c la im may be by fa i lure to
perform work, by conve yance, by absence, and by lapse of time. The
abandonment of a mining claim is a question of intent. To constitute
an abandonment of a mining c la im, there must be a going away and a
relinquishment of rights, with the intention never to return and with a
voluntary and indep endent purpose to surrender the locat ion or c la im
to the next comer. Cf:  forfeiture.
Ab bé jar In mineral processin g, a porcelain jar used for laboratory
batch grind ing tests in ceram ic ware. (Fryor, 1958)
Ab bé refractom eter An instrument to determine the index of re frac-
tion of a l iquid between tw o high-in dex glass prisms. Cf:  refractometer.
Ab bé the ory The v is ib i li ty of an object under the microscope is d i -
rectly proportional to the wavelength of l ight, and inversely to the
apertu re of lens. (Pryor, 1963)
Ab bé tube mill A gear-driven tube mill supp orte d on a pair of riding
r ings and dis t inguished by an Archimedes spira l , through which the
ore is fed and disch arged . Grin ding is effecte d by flint pebbles fed into
the mill . See also:  ball mill.  (Liddell, 1918)
AB C system A method of se ismic surveyin g by which the e f fect of
i rregular weather ing thickness may be determined by a s imple ca lcu-
lat ion from reciprocal p lacement of shotholes and se ismometers . The
method was or ig inal ly used to so lve refract ion problems ar is ing from
irregularities in the top of the high-velocit y layer . (AGI , 1987)
Ab el ' s reagent Etching agent consist ing of 10% chromium tr ioxide in
water. Used in the analy sis of carbon steels. (Bennett, 1962)
abern athyi te A tetragonal mineral , K(U0 2)(As0 4)4H i0; in smal l ye l -
low crysta ls ; in the Temple M ountains , UT.
abe rrat ion (a) T he failure of a lens or mirror to bring the light rays to
the same focus. When aberration is due to the form of the lens or
mirror, it is called spherical aberration. When due to the different
refrangibility of l ight of different colors, it Is called chromatic aberra-
tion. Wh en present in mag nifiers it often causes inaccurate decisions
as to flawl essn ess or color of gem s, (b) Distortion prod uced by a lens.
It is spherical if a fiat image appears closer to the viewer in the middle
than towa rd the edg es of the field of vie w. It is chrom atic if the visible
spectrum is spread to g ive both a red and a b lue image. Cf :  achromatic;
aplanatic lens; aplamchromatic lens.
  See also:
 chromatic aberration.
abi me A large, steep-side d vertical shaft ope nin g at the surface of the
grou nd. (AG I, 1987)
ablat ion breccia  solution breccia.
A.B. Me co-M oore A bulky machine that cuts a deep web of coal up
to 6 ft (1.8 m) and is used in cyclic min ing in me dium to thick seams. It
runs on the floor of the seam and do es not require a prop-free front. It
carries two horizontal j ibs, one cutting at floor level and the other at a
height dependin g on seam conditions . (Nelson, 1965)
Ab ne y leve l A surveying instrument for taking levels up s teep s lopes;
a lso used as a c linometer . (Ham mon d, 1965)
abnorm al p lace A workin g p lace in a coal mine with adverse geologi-
ca l or other condit ions and in whic h the miner i s unable to earn a wage,
based on the pricelist, equal to or above the minimum wage. A term
genera lly associated with stalls or pillar meth ods of work ing. (Nelson,
1965)
abra ser A device for asses sing the we ar resistance of surfaces. The
specimen to be tested is rubbed alternately by the flat faces of two
weighted abrasive wheels that revolve in opposi te d irect ions through
fr ict lonal contact with the specimen and exert a combined abrasive ,
comp ress ive , and twist ing act ion twice in each revolut ion of the speci-
men holder . (Osborne , 1956)
abrasion (a) The mechanical wearin g away of rock surfaces by fr ic-
t ion and impact of rock part ic les t ransported by wind, ice , waves ,
runn ing .water, or grav ity. Syn: corrosion.  Cf : attrition.  (AG I, 1987) (b)
The wear ing away of d iamonds, dr i l l -b i t matr ices , and dr i l l -s tem
equ ipm entb y fr ic tional contact with the rock mater ia l penetrated or by
contact with the cuttings produced by the action of the drill bit in
drilling a boreh ole. (Long, 1960)
abrasion hardn ess Hardness expressed in quant i tat ive terms or num-
bers indicating thede gree to wh ich a substance res is tsbeing worn awav
by frictional contact with an abrasive material, such as silica or carbo-
run dum grits. Als o called abra sion resistance; wear resistance. (Long,
1960)
abrasion ind ex The percentage of a specia l ly prepared 3- in by 2- in
(76-mm by 51-mm) sample of coke remaining on a 1/8-in (3.2-mm)
mesh British Standards test sieve after the sample of coke has been
subjected to a standardized abrasion procedure in a rotating drum.
(BS,
 1961)
abr asiv e (a) An y natural or artificial substan ce suitable for grinding,
pol ishing, cutt ing, or scouring. Natural abras ives inc lude diamond,
emery, garnet , s i l ica sand, d iatom ite , and pum ice; manufactured abra-
sives include esp., sil icon carbide, fused alumina, and boron nitride.
(AGI , 1987) (b) T end ing to abra de or wea r awa y. (AGI, 1987)
abras ive b last in g respirator A respirator des igned to protect the
wearer f rom inhalat ion or impac t of , and abrasion by, mater ials used
or generate d in abrasive blastin g. (AN SI, 1992)
abrasive forma tion A rock consist ing of smal l , hard, sharp-cornered,
angular f ra gments , or a rock, the cutt ings f rom which, produced b y the
action of a drill bit, are hard, sharp-cornered, angular grains, which
grind a wa y or abrade the metal on bits and drill-stem equipm ent at a
rapid rate. Syn: abrasive ground.  (Lon g, 1960)
  abrasive formation.
abrasive hard ness test Test em ployin g a rotat ing abras ive wheel or
plate against which specimens are held . The specimens are abraded
for a given number of revolutions, and the weight of material lost is a
measure of the abras ive hardness . (Lewis , 1964)
abraum sal ts  abraumsalze.
abrau msa lze Ger . Mixed sul fates and chlor ides of potass ium, so-
dium, and magnesium overlying the rock salt in the Stassfurt salt
deposi ts . Syn:  abraum salts; stripping salt.  (Holm es, 1928)
abriachan ite An earthy, amo rphou s var iety of crocidoli te asbestos .
(Dana, 1914)
abs olute (a) In chem istry, free from impurity or admix ture. (Hess)
(b) In phys ics, not dep end ent on any arbitrary standard. (Hess) (c)
Frequently used in the trades to indicate a thing as being perfect or
exact. Ab bre v. abs. (Crisp in, 1964)
absolu te age The geologic age of a foss il organism, rock, or geologic
feature or even t given in units of time, usua lly years. Com mo nly used
as a syn. of isotopic age or radiome tric age, but may also refer to ages
obtained from tree rings, varves, etc. Term is now in disfavor as it
implies a certainty or exactness that may not be possible by present
dat ing methods; i .e . , two absolute ages for the same pluton may dis-
agree by hundreds of mi l l ions of years . Cf :
  relative age.
  actual age.
(AGI, 1987)
absolute atm osphe re An absolute unit of pressure equal to 1 mi ll ion
t imes the pressure pro duced on 1 cm
2
 by the force of 1 dyn . (Fay, 1920)
absolute bul k s trength A measure of avai lable energy per unit vol -
ume of explos ive . Syn: bulk strength.  See also:  relative bulk strength.
absolute chronolo gy Geoch ronology in which the t ime-order is based
on absolute age , usual ly measured In years by radiometr ic dat ing.
1
absolute da i ly range abyss a l zone
rather than on superposition and/or fossil content as in relative chro-
nolo gy. (AGI , 1987)
abso lute dai ly range During the 24 h of the day the di f ference between
the maximum easter ly and maximum wester ly va lues of the magnet ic
declinatio n at any point. (Mason , 1951)
absolut e humid ity The content of water vapor in a ir , expressed as the
mass of water per unit volume of air. Cf:
  relative humidity.
  See also:
humidity.  (AG I, 1987)
abs olut e iso hy ps e A line that has the properties of both constant
pressu re and constant height abo ve mean sea level. Therefo re, it can
be any contour line on a constant-pressure chart, or any isobar on a
constan t-height chart. (Hunt, 1965)
absolute ow ner ship In law, an unqual i f ied t it le to property and the
u n q u e s t i o n e d r i g h t t o i m m e d i a t e a n d u n c o n d i t i o n a l p o s s e s s i o n
thereof. Applies to mining claims and properties. (Standard, 1964;
Hess)
abso lutep erm eab i l i ty A measure ofposs ible f low of a s tandard liquid
under f ixed condit ions through a porous medium when there is no
reaction betwe en the liquid and the solids. This mea sure is arbitrarily
taken for isothermal viscous flow. It can be duplicated with gases if
tests are so conducted that extrapolation to infinite pressure can be
made; speci f ic permeabi l i ty . (Hess)
absolute poten t ia l True potent ia l d i f ference between a metal and the
solution in wh ich it is imm ersed. (Pryor, 1963)
abs olut e pres sure (a) Total pressure at a point in a fluid equa ling the
sum of the gage pre ssure and the atmosph eric pressure. (Webste r 3rd,
1966) (b) Pressu re meas ured w ith respect to zero pressure, in units of
force per unit of area. (CTD , 1958)
abs olut e roof The entire ma ss of strata overlyin g a coal seam or a
subsur face point of reference. See also;
 nether roof.
absolute sca le  Kelvin temperature scale.
absolu tetem pera ture Tempe rature reckoned from absolute zero . See
also:
 temperature.
  (Han dboo k of Chem . & Phys., 2)
absolute t ime Geologic t ime measured in terms of years by radioact ive
decay of e lements . Cf :
  relative time.
  See also:
  geochronology.
a b s o l u t e v i s c o s i t y  viscosity coefficient.
absolute wei ght s trength A measure of avai lable energy per gram of
explos ive . Syn: weight strength.  See also:  relative weight strength.
absolute zero The temperature at which a gas would show no pressure
if the gener al law for gases wo uld ho ld for all tempera tures. It is equal
to -273.16 "Co r
 temperature.
  ( H a n d bo o k o f C h e m . & P h y s „
2
absor bed water Water held mechanical ly in a soi l mass and having
physica l prop ert ies not substant ia l ly d i f ferent f rom those of ordina ry
wate r at the sam e temperatu re and pressure. (ASCE , 1958)
absorb ent format ion A rock or rock mater ial , which, by v irtue of i ts
dryn ess, por osity, or perme ability, has the ability to drink in or suck up
a dr i l l ing l iquid, as a sponge absorbs water . Syn:  absorbent ground.
(Long , 1960)
a b s o r b e n t g r o u n d  absorbent formation.
absorb ents Substances , such as woo d meal and wheat f lour , that are
forms of low ex plos ive w hen mixed with metal lic n i trates and tend to
reduce the b last ing po wer of the explos ives , making them sui table for
coal blasting. (Coop er, 1963)
absorbe r (a) A n apparatus in which gases are brought into intimate
contact with an extended surface of an absorbing fluid so that they enter
rapidly into solution. (Hess) (b) The resistance and capacitance in
series that is placed across a break in an electrical circuit in order to
damp any poss ible osc i l latory c ircui t and would tend to maintain an
arc or spark wh en a current is interrupte d. Syn:  spark absorber.  (CTD,
1958) (c) Any material that absorbs or stops ionizing radiation, such
as neutrons, gam ma rays , alpha particles, and beta particles. (Lym an,
1964)
absorpt iom eter A device for measuring the solubi li ty of a gas in a
liquid. (Bennett, 1962)
absorp t ion (a) The phenom enon observed when a p leochroic mineral
is rotated in plane p olarized light. In certain positions, the mineral is
darke r than in others, owin g to the absorption of l ight, (b) In hydr ol-
ogy, a term applied to the entrance of surface water into the lithosphere
by all methods. (AGI, 1987) (c) The reduction of light intensity in
transmiss ion through an absorbing substance or in ref lect ion from a
surface . In crysta ls , the absorpt ion may vary with the wave length and
with the electric vector of the transmitted light with respect to crystal-
logr aph y directions , (d) An y mechanism by which energy, e .g . , e lec-
trom agne t ic or se ism ic , i s con vert ed into heat , (e) Tak ing up,
assimilation, or incorporation, e.g., of l iquids in solids or of gases in
liquids. Cf: adsorpt ion. Syn: occlusion,  (f) The entrance of surfa ce wate r
into the li thosphere by any method,
absorpt ion hygro me ter A type of hygrometer with which the water
vapo r content of the atmosphere is measured by means of the absorp-
t ion of vapor by a hygroscopic chemical . The amount of vapor ab-
sorbed may be determined in an absolute manner by weighing the
hygroscopic mater ia l , or in a nonabsolute manner by measuring a
2
physica l property of the substance that var ies with the amou nt of wa ter
vapo r absorbed. The l ithium chlor ide humidity s tr ip and carbon-f i lm
hygrometer e lement are examples of the lat ter. (Hunt , 1965)
absorpt ion loss (a) The loss of water occurr ing during ini t ia l fi l l ing of
a reservoir in wet ting rocks and soil. (H am mo nd, 1965) (b) T hat part
of the transmiss ion loss due to diss ipat ion or the conve rs ion of soun d
energy into some other form of ener gy, usual ly heat . This convers ion
may take place within the me dium i tse lf or upon a ref lect ion at one of
its boun daries . (Hy, 1965)
absorp t ion rate (a) The rate , expresse d in quant i tat ive terms, at whic h
a l iquid, such as a dr i ll ing c irculation me dium , is absorbed by the rocks
or rock materials penetrated by the drill bit. (Long, I960) (b) The
amoun t of water absorbed w hen a br ick is part ia l ly imm ersed for 1 min;
usual ly expressed e i ther in grams or ounces per min ute . Als o ca l led
suction rate; initial rate of absorp tion. (AC SG , 1961)
absorp t ion spectra Speci f ic wav elen gths of e lectrom agnet ic radiat ion
have precise ly the energy to cause atomic or molecular transi t ions in
substances they are pass ing through; their removal f rom the incident
radiat ion produces reduct ions in intensi ty of those wavelengths , or
absorpt ion spectra , character is t ic of the substance under s tudy. Cf :
emission spectra.
absorpt io n spectrum The array of absorpt ion band s or l ines seen
when a cont inuous spectrum is t ransmitted through a se lect ive ly ab-
sorbing medium. (AGI, 1987)
absorpt ion tower A tower in which a l iquid absorb s a gas .
abund ant v i tra in A f ie ld term denot in g, in accordan ce with an arbi-
trary sca le established for use in descr ib ing b and ed co al , a f requenc y of
occurrence of v i tra in bands compris ing 30% to 60% of the tota l coal
layer. Cf: dominant vitrain: moderate vitrain; sparse vitrain.  (AG I, 1987)
abutm ent A surface or mass pro vide d to withstan d thrust , for exam-
ple, the end supp orts of an arch or bri dge . In coal min ing, (1) the we ight
of the rocks above a narrow roadway is t ransferred to the sol id coal
a long the s ides , whic h act as abutm ents of the arch of s trata span ning
the roadway; and (2) the weight of the rocks over a longwal l face is
transferred to the front abutment (the solid coal ahead of the face) and
the back abutment (the settled packs behind the face). See also:  over-
arching weight; pressure arch; load transfer.   Syn:  arch structure.  (Nelson,
1965)
abutm ent load In underground m ining, the wei ght of rock above an
excavat ion that has been transferred to the adjoining wa l ls . (Pryor ,
1963)
abutm ent p i l lars Pi l lars intended to suppor t vert ica l load in excess of
the weight of the stra ta direct ly above them. Gene ral ly , these abutment
pi l lars are large p i l lars adjacent to smal ler p i l lars , sometimes ca l led
yield pillars, which are incapable of carrying the weight of the strata
abov e them. (SME, 1992)
a b y s m a l  abyssal.
abysm al sea That part of the sea occu pyin g the ocean bas ins proper .
(Fay, 1920)
abyss (a) A very deep, unfathomable p lace . T he term is used to refer
to a particularly deep part of the ocean, or to any part below 3,000
fathom s (18,000 ft or 5.5 km). Syn:  pit; pot; pothole; chasm; shaft.  (Hunt,
1965) (b) Syn:
  pit; pot; pothole; chasm; shaft.
abyssa l (a) P erta ining to an igneous intrusion that occurs at consider-
able depth, or to the resulting rock; plutonic. Cf:   hypnbyssal.  (AGI,
1987) (b) Pertaining to the ocean environment or depth zone of 500
fathoms (3,000 ft or 915 m) or deeper; also, pertaining to the organisms
of that enviro nme nt. (AGI, 1987) (c) Of, or perta ining to, dee p within
the Earth, the oceanic deeps below 1,000 fathoms (6,000 ft or 1.83 km),
or great dept hs of seas or lakes wher e light is abse nt. See also:
  plutonic.
(AGI, 1987) (d) In ocea nogr aph y, relating to the great est dept hs of the
ocean; relating to the abyssa l realm. Syn :  abysmal.  (CTD , 1958)
abys sal deposi t A deposi t o f the dee p sea , accum ulat ing in depths of
more than 1,500 fathoms (9,000 ft or 2.7 km) of water; these deposits
comprise the organic oozes , var ious m uds, and red c lay of the deepest
regions. (CTD , 1958)
abyssal in ject ion Tl ie process by whic h mag mas , or ig inat ing at con-
s iderable depths , are considered to hav e been dr iven u p throug h de ep-
seated contraction fissures,
aby ssa l pla in An area of the ocean floor with a slop e of less than 1 in
1,000 or fla t, near ly level areas that occu py the deep est port ions of m any
ocean basins. (Schieferdecker, 1959)
abyssa l rea lm The deep waters of the ocean belo w 1 ,000 fathom s or
6,000 ft (1.83 km ).
abyssa l theory A theory of mineral-deposi t format ion invo lv ing the
separat ion and s inking of ore minerals be low a s i l icate shel l dur in g the
cooling of the Earth from a liquid stage, followed by their transport to
and deposition in the crust as it wa s fract ured (Shan d, 1947). Mo der n
thought ascr ibes more complex or ig ins to mineral deposi ts . (AGI,
1987)
abyssal zone The marine- l ife zone of the deep sea emb racing the water
 
a b y s s o b e n t h i c
a c i d i c
abysso benthi c Relating to that part of the abyssal realm that includes
the ocean floor; pertaining to or living on the ocean floor at great depths.
(CTD, 1958)
abyssol i th  batholitli.
aby ssop ela gic (a) Relating to that part of the abyss al realm that ex-
clud es the ocean floor ; floating in the dep ths of the ocean. (CT D, 1958)
(b) Pertainin g to that portion of the deep wa ters of the ocean that lie
belo w d epth s of 6,000 ft (1.83 km). (AG I, 19S7)
acanthite A monoclinic mineral, 4[Ag2S]; dimo rphous with argentite,
pseud ohexag onal, in slender prisms; sp gr, 7.2 to 7.3; a source of silver,
accelerated weathe ring test A test to indicate the effect of weath er on
coal, in which the coal is alternately exposed to freezing, wetting,
warm ing, and light; the alternation may be varied to suit. This test may
be applied to other bituminous materials. (Hess)
acceler ator (a) A machin e that accelerates electrically charg ed atomic
particles, such as electrons, protons, deuterons, and alpha particles, to
high velocities. (Lym an, 1964) (b) A substance ad ded to increase the
rate of a chemica l reaction. (Nelson , 1965)
accelerometer A seismometer with response linearly proportional to
the acceleration of earth materials wit h whi ch it is in contact. (AG I,
19S7)
accented contour  index contour.
acceptor A charge of explosives or blasting agent receiving an impu lse
from an explodin g donor charge. Syn: receptor. (Meyer, 1981)
accessory (a) App lied to minerals occurring in small quantities in a
rock. The p resence or absence of these minor minerals does not affect
the classificati on or the nam ing of the rock. (Holm es, 1928) (b) Frag-
ments derived from previously solidified volcanic rocks of related
origin; i.e., the debris of earlier lavas and pyroclastic rocks from the
same cone. See also; accessory mineral,  (c) Said of pyroc lastics that are
formed from fragments of the volcanic con e or earlier lavas; it is part of
a classification of volcanic ejecta based on mode of origin, and is
equi valen t to resurgen t ejecta. Cf; auxiliary.  (AGI, 19S7)
accessory element
accessory mineral An y mineral the presence of whic h is not essential
to the classification of the rock. Accessory minerals generally occu r in
minor amounts; in sedimentary rocks they are mostly heav y minerals.
Cf : essential mineral.  Syn: accessary.  (AG I, 1987)
accessory plate (a) The quartz wed ge inserted in the microscope sub-
stage above the polarizer in order to estimate birefringence and to
determ ine optical sign of uniaxial min erals. Cf:  quartz wedge.  (Pryor,
1963) (b) The selenite plate that give s the sensitive tint of a specim en
betwe en crossed nicols. (Pryor, 1963) (c) The mica plate that retard s
yellow light. (Pryor, 1963) (d) In polarized-light microscop y, an op-
tical device that may be inserted into the light train to alter light
interference after passage throu gh, or reflection by, a crystalline mate-
rial; e.g., quartz wed ge, mica plate, gyps um plate, or Bertrand lens, (e)
In polarized-light microscopy, an optical compensator that may be
inserted into the light train to alter birefringence after light passage
through or reflection bv an anisotropic material; e.g., quartz wedge,
mica plate, gvps um plate, or Berek compensator. Syn: gips plate; glim-
mer plate; compensator.  Cf : Berek compensator; gypsum plate.
access road A route constructed to enable plant, supplie s, and vehicles
to reach a mine, quar ry, or opencast pit. In remote and isolated region s,
the provision of an access road mav be very costly. (Nelson, 1965)
accidental inclusion  xenolilh; xenocn/st.
accordion roller conve yor A roller convey or with a flexible latticed
frame that permits variation in length,
accretion vein A vein formed by the repeated filling of a channelw ay
and its reopening by the development of fractures in the zone under-
going mineralization,
accum ulation (a) In coal mining, bodies of combustible gases that
tend to collect in higher parts of mine workings and at the edge of
goaves and w astes. They are found in cavities, at ripping lips, at other
sheltered places protected from the ventilating current, and at the
higher sides of rise faces. (Mason, 1951) (b) The concentration or
gathering of oil or gas in some form of trap. Comm ercial accum ulation
is a volum e or quantity sufficient for profitable exploitation. (AGI,
1987)
accumulat ive rock  cumulate.
accum ulator (a) A cylinder containing water or oil unde r pressure of
a weighted piston for hydraulic presses, hoists, winches, etc. It is
between the pumps and the presses, keeps a constant pressure on the
system, and absorbs shocks, (b) A storage battery, (c) In ocea nog ra-
phy, a spring of rubber or steel attached to a trawling warp, to lessen
any sudden strain due to the trawl catching. (CTD, 1958)
accumulator conveyor Any conveyor designed to permit accumula-
tion of packages or objects. Usua lly roller, l ive roller conve yor, roller
slat conveyor, or belt conveyor,
accuracy The degree of conformity with a standard, or the degre e of
perfection attained in a measurement. Accura cy relates to the quality
of a result, and is distinguished from precision, which relates to the
quality of the operation by which the result is obtained. (AGI, 1987)
acetamide A tr igonal mineral , CH5CONH2. Syn:  acetic acid amine;
ethanamide.
acet ic acid am ine  acetamide.
acety lene The most brilliant of illuminating ga ses, C2H2. It may be
produced synthetically from its elements, by incomplete combustion of
coal gas, and comm ercially from calcium carb ide, CaC2. It also may be
produced by reaction with water . Used in manufacturing explosives .
Formerly used as an illuminating gas in mines and around drill rigs.
Wh en combined with oxygen, acetylene burns to produce an intensely
hot flame and hence now is used principally in welding and metal-cut-
ting flame torches. Syn:  ethyne; ethine.  Cf : gas.  (Standard, 1964; Ben-
nett, 1962; Long, 1960)
acetylene lamp  carbide lamp.
acet ylen e tetrabro mide Yel lowi sh liquid; CHBr:CH Br2; sp gr, 2.98 to
3.00; boiling point, 239 to 242 "C with deco mpo sition (at 760 mm); also,
boiling point, 151 °C (at 54 mm); melting point, 0.1 °C; and refractive
index, 1.638. Used for separating minerals by specific gravity; a solvent
for fats, oils, and waxes; a fluid in liquid gases; and a solvent in
microscopy. (CCD, 1961)
acha valite Former name for iron selenide , FeSe.
Ach eso n grap hite Artificial graph ite mad e from coke by electric fur-
nace heating. (Bennett, 1962)
Ach eso n process A process for the produ ction of artificial or synthetic
graphite. It consists of sintering pulve rized coke in the Acheso n fur-
nace at 2,760 to 3,316 "C. (He nde rson , 1953)
achirite Former name for dioptase.
achroite A colorless variety of elbaite tourma line used as a gemstone.
achrom atic In microscopy , a com pou nd lens that does not spread
w h i t e l i g h t i n t o i t s s p e c t r a l c o l o r s . C f :  aberration.  See also:
aplanachromaticlens.
acicu lar (a) A mineral consisting of fine need lelike crystals; e.g., na-
trolite. (Nelson, 1965) (b) Slender needlelike crystal, (c) Refers to
needlelike crystals. Cf:  equant; sagenitic; tabular; rodlike.
a c i c u l a r b i s m u t h   aikinite.
acicular pow der In pow der meta l lurgy , need le-shap ed part icles .
(ASM, 1961)
acicul i te  aikinite.
 
C. (b) A substance
containing hydrogen that may be replaced by metals with the formation
of salts. (CT D, 1958)
acid Besseme r converter One l ined with acid refractories ,
acid bottom and linin g The inner bottom and lining of a melting
furnace , consisting of materials like sand, siliceo us rock, or silica brick,
which give an acid reaction at the operating temperature. Syn:  acid
lining.  (ASM , 1961)
acid clay (a) A clay that is used ma inly as a decolorant or refining
agent, and sometimes as a desu lfuriz er, coagu lant, or catalyst, (b) A
clay that y ie lds hydrogen ions in a water suspension; a hydrogen c lay ,
acid cure In uranium extraction, sulfation of moist ore before leaching.
(Pryor, 1958)
acid -dip survey A method of determ ining the angu lar inclination of a
borehole in wh ich a glass, test-tubelike bottle partly filled with a dilute
solution of hydrofluoric acid is inserted in a watertight metal case.
When the assemblage is lowered into a borehole and left for 20 to 30
min, the acid etches the bottle at a  level plane from w hich the inclination
of the borehole can be measured. Cf:  Kiruna method.  Syn:  acid-dip test;
acid test; acid-etch tube.  (Long, 1960)
acid-dip test  acid-dip survey.
acid drain age Water with a pH of less than 6.0 and in whic h total
acidity exceeds total alkalinity; discharged from an active, inactive, or
abandoned surface coal mine and reclamation ope rat ion,
acid electric furnace An arc furnace havin g an acid refractory hearth,
acid embrit t leme nt A form of hydrog en embritt lement that may be
indu ced in some metals by acid treatment. (AS M, 1961)
acid-etch tube A soda-lime glass tube charged with dilute hydro flu-
oric acid, left in a borehole for 20 to 30 min to measure inclination as
indicated by the angle of etch line on the tube. May be fitted in a
clinometer. Syn:  acid-etch vial; culture tube; etch tube; sargent tube.  See
also: acid-dip survey.  (Pryor, 1963; Lon g, 1960)
acid-etch via l  acid-etch tube.
acid flux Metallurg ically acid material (usually some form of silica)
use d as a flux . (Bennett, 1962)
acid -form ing materi als Earth materials that contain sulfid e minerals
or other materials that, if exposed to air, water, or wea theri ng processes,
form acids that may create acid drainage,
acidic (a) A descriptive term app lied to those igneous rocks that
contain more than 60% silica. Acid ic is one of four subd ivisions of a
widely used system for classifying igneous rocks based on their silica
content: acidic, intermediate, basic, and ultrabasic. (AGI, 1987) (b)
Appl ie d loosely to any igneous rock composed predomina ntly of l ight-
colored minerals havi ng a relatively low specific gravity. Cf: felsic.  Syn:
silicic.
3
acquired lands
acidiza t ion The process of forc ing ac id into a l imestone, dolomite , or
sandstone in order to increase perm eabi l i ty and porosi ty by dissolv in g
and rem ovin g a part of the rock constitue nts. It is also used to remo ve
mud injected during d r i l l ing . The general object ive of ac idizat ion is to
increase produc t iv i ty . Syn: acidizing.  (AG I, 1987)
acidize To treat a l imeston e or dolomit ic formation with di lute hydro-
chloric acid to enla rge its vo id spac es. (Whe eler, 1958)
a c i d i z i n g  acidization.
acid leach Meta l lurgica l process for d issolut ion of metals by means of
ac id so lut ion. Exam ples inc lu de extract ion of copper f rom oxide- or
sul f ide-bear ing ore and dissolut ion of uranium from sandstone ores .
Acid leaching can occur on heap- leach pads or in s i tu ,
a c i d l i n i n g  acid bottom and lining.
acid mine drainag e (a) A cidic draina ge f rom bi tuminou s coal mines
containing a high concen trat ion of ac idic sul fates , esp. ferrous sul fate .
See also:  acid water,  (b) D rain age wi th a pH of 2.0 to 4.5 from m ines
and mine wastes . I t resul ts f rom the oxidat ion of sul f ides exposed
during mining, which pr oduc es sul fur icac id and sulfate sa l ts . The ac id
dissolves minerals in the rocks , further degrading the qual i ty of the
drainage water . (AGI, 19S7)
acid mine wate r (a) Min e water that contains f ree sul fur ic ac id ,
mainly due to the weather ing of i ron pyr i tes . A pi t water , which
corrodes i ron pipes and pumps, usual ly contains a high proport ion of
sol ids per ga l lon, pr incipal ly the sul fates of i ron, chief ly ferrous and
alumina. See a lso:  acid water.  (Nelson, 1965) (b) Whe re sul f ide min-
era ls break down under chemical inf luence of oxygen and water , the
mine drainage becom es ac idic and can corrode i ronwork. I f i t reaches
a r iver system, bio logica l dam age m ay a lso resul t . (Pryor , 1963)
a c i d n e u t r a l i z e s C a l c i u m c a r b on a t e , C a C 0 3 , m a g n e s i u m c a rb o n a t e,
MgCO.i , and china c lay , whic h neutra l ize f ree ac ids , thereby p revent in g
explos ives f rom decomposing in s torage. They a lso have a cool ing
ef tectan d tend to reduce the sensi t iv i ty of the explos ive . (Cooper , 1963)
acid open-h earth s tee l Low -pho sph oru s pig i ron treated in an ac id
(silica or sand)-lin ed furnac e. (Me rsere au, 1947)
acid ore
  siliceous ore.
acid process A s tee lm aking proce ss—B essem er, open-hearth, or e lec-
tr ic—in which the furnace is l ined with a s i l i ceous refractory , and for
which pig i ron low in phosphorus is required, as this e lement i s not
remov ed. See a lso:
  acid steel; basic process.
  (CTD , 1958)
acid-recovery operat or In the coke products industry , a person wh o
recovers sul fur ic ac id used in process ing coke-gas bypr oducts by cook-
ing s ludge with s team in ac id regenerator pots . Syn:  acid regenerator.
(DOT, 1949)
acid refractory mater ia l A general term for those types of re fractory
material that contain a high proportion of silica; e.g., sil ica refractories
(greater than 92% SiCy and s i l iceous refractor ies (78% to 92% SiOj) .
The name d er ives f rom the fact that s il ica behaves chem ical ly as an ac id
and at h igh temperatures reacts with bases such as l ime or a lkal ies .
(Dodd, 1964)
acid refractory prod uct Refractory product made of c lay-s il ica mix-
ture or pure silica. (Rose nthal, 1949)
acid regenerator  acid-recovery operator.
acid rock drain age Dra inag e that occurs as a resul t o f natural oxida-
t ion of sul f ide minerals contained in rock that i s exposed to a ir and
water . I t i s not conf ined to mining act iv i t ies , but can occur wher ever
sul f ide-bear ing rock is exp osed to a ir and water . Abbr ev. AR D.
acid s lag S lag that contains substant ia l amou nts of act ive s il ica ,
ac id s ludge Produ cts of re f ining of tar , shale o i l , and petroleum in
whic h sul fur ic ac id reacts to form a sul fonic ac id mixture , green ac ids ,
and mahogany ac ids and sa l ts . Used in the f lotat ion process and in
prop rietary collec tor agent s for flotatio n of iron ores. (Pryor, 1958)
acid soil A soil wi th a pH of less than 7.0. (AGI , 1987)
acid s tee l Stee l melted in a furnac e with an ac id bottom and l in ing and
under a s lag containing an excess of an ac id substance, such as s i l ica .
See also: acid process.  (ASM , 1961)
acid s trength Related to abi l i ty to l iberate hydro gen ions to so lut ion,
and hence to e lectr ica l conduct iv i ty of equivalen t aqueou s so lut ions of
acids. (Pryor, 1963)
acid test (a)  acid-dip survey,  (b) A severe or decisiv e trial, as of usabil-
ity or authe nticity. (Long , 1960)
acid water Wa ter charged natural ly with carbon dioxide. Als o ap-
pl ied to natural waters containing sul fur compounds, esp. sul fates .
See also:
 acid mine water; acid mine drainage.
a c i f o r m N e e d l e - s h a p e d .
ac ini fo rm A mineral aggre gate shaped like a c luster of grapes . Also ,
full of small kerne ls like a grap e. Syn:  acinose; acinous.
acinose (a) Grap el ike; app l ied to the s tructure of c lustered mineral
aggregates . Syn:  aciniform; acinous,  (b) Gran ulated ; l ike grap e seeds;
appl ied to the texture of some mineral aggregates ,
ac inote Former nam e for act inol i te .
a c i n o u s  aciniform; acinose.
aclin al A little-used term said of strata that hav e no inclination; hori-
zontal. Syn:
  (AG I, 1987)
acl inic  aclinal.
aclinic l in e Tine line through those points on the Earth's surface at
which the magnetic inclination is zero. The aclinic l ine is a particular
case of an isoclinic line. (Hun t, 1965)
acm ite A bro wn variety of aegirine having pointed terminations. See
also:
 aegirine; pyroxene.
aco po lado Me x. Ore containing 50 to 60 oz/ st (1.56 to 1.88 kg/t ) of
silver. (Hess)
acoust ic Used whe n the term that i t modif ies des ignates something
that has the properties, dimensions, or physical characteristics associ-
ated with sound wav es. (Hy, 1965)
acoust ica l wel l logging An y determinat ion of the physica l propert ies
or dimensions of a borehole by acoust ica l means, inc luding measure-
men t of the dep th of fluid level in a well. (AGI, 1987)
acoust ic at tenuat ion lo g In theory , a log des igned to measure the
manner in which the energy of e last ic waves is d iss ipated in pass ing
through rock. Al tho ugh no pract ica l log of this type has yet evolved ,
the belief that a log of this parameter would permit the estimation of
the permeabi l i ty of formations would seem to ensure such a develop-
ment since no log has been develo ped to record perm eability. (Wyllie,
1963)
acoust ic d ispers ion The change of speed of sound with f requency.
(Hunt, 1965)
acoust ic impeda nce The acoust ic impedance of a g iven surface area of
an acoustic medium perpendicular, at every point, to the direction of
propagat ion of s inusoidal acoust ic waves of g iven frequency, and
having equal acoust ic pressures and equal volume veloci t ies per unit
area at every point of the surface at any instance, is the quotient
obtained by div iding (1) the phasor corresponding to the acoust ic
pressu re by (2) the phaso r correspondin g to the vol um e velocity. See
also:  impedance.  (Hun t, 1965)
acoust ic interfero mete r An instrument for makin g physica l observa-
tions upon stand ing wave s. It ma y be used, e.g., to mea sure ve locity,
wave length, absorpt ion, or impedance. (Hunt , 1965)
acoust ic log A cont inuous record made in a borehole showing the
veloci ty of soun d w ave s over short d is tances in adjacent rock; ve loc i ty
is related to porosity and nature of the liquid occu pyin g pores. (AGI,
1987)
acoust ic-rad iat ionpre ssure A unidirect ional s teady-state pressure ex-
erted upon a surface exposed to an acoust ic wave. Such a s teady
pressure is usually quite small in magnitude and is really observable
only in the presen ce of very intense sound wav es. (Hunt, 1965)
acoust ic radiom eter An instrument for measuring acoust ic-radiation
pressure by determining the unidirectional steady-state force resulting
from reflection or absorption of a sound w ave at its boun daries . (Hunt,
1965)
acoust ic res is tance Product of longi tudinal wav e ve loc i ty and densi ty ,
being the property that controls the ref lect ive power at a boundary
plane. (Schieferde cker, 1959)
acou stics The study of soun d, includin g its produ ction, transmission ,
reception, and utilization, esp. in fluid media such as air or water.
With refer ence to Earth sciences, it is esp. relevant to ocea nogr aph y.
The term is sometimes used to inc lude compress ional wav es in so l ids ;
e.g., seism ic wa ves . (AGI, 1987)
acous tic scatt ering The irregular reflection, refraction, or diffractio n of
soun d wav es in ma ny directions. (Hy, 1965)
acoust ic sou ndi ng The indirect evaluat ion of water depth, us ing the
principle of measuring the length of time necessary for a sound wave
to travel to the bottom, reflect, and travel back to the water surface.
(Hunt, 1965)
acous tic-stra in gag e An instrument for mea suring strains; e.g., in
concrete linings to shafts or roadw ays . It contains a length of fine wire
under tension, the tension being varied by the strain to which the gage
is subjected . The measu reme nt mad e is that of the frequ ency of vibra-
t ion of the wire when i t i s p lucked by means of an e lectromagnet ic
impulse , and this measurement can be made with great accuracy . The
gage is highly stable, and readings can be made over a period of years
without any fear of zero drift. See also: electrical resistance strain gage;
mechanical extensometer.  (Nelson, 1965)
acoust ic theodol i te An instrument des igned to provide a cont inuous
vertical pro file of ocean currents at a specific location. (Hunt, 1965)
acoust ic wa ve (a) The waves that contain sound energy and by the
motion of which sound energy is transmitted in air, in water, or in the
ground. The w ave may be descr ibed in terms of change of pressure , o f
particle displacement, or of density. (AGI, 1987) (b) Used increas-
ingly to study the physical properties of rocks and composition of
gases. Investigation s may be made both in situ and in the laborato ry.
(Nelson, 1965)
acq uired lan ds Defin ed by the U.S. Department of the Interior as
" lands in Federal ownership which were obtained by the Government
through purchase , condemnation, or g i f t , or by exchange for such
purchase d, condem ned, or donated lands, or for t imber on such lands.
4
a d d i t i v e
They are one category of public lands." Public land laws are generally
inapp licable to acquired lands. (SME, 1992)
acre (a) A mea sure of surficial area, usua lly of land. The statute acre
of the United States and England contains 43,560 ft
2
2
; 4,047
m
2
; or 160 squar e rods). The so-called Scotch acre contains about 6,150
yd
2
2
). There are various
special or local acres in England (as in Cheshire or among the hop
growers) , va ry ing from 440 yd
2
2
 (8,361
m
2
). (Standard, 1964) (b) Can. In Quebec, a l inear measure that
equ als the squ are ro ot of 43,560, or app rox . 208.7 ft (63.6 m). (Fay,
1920) (c) For the calculation of coal reserves, a conven ient rule is to
allow 1,200 st/ft (coal thickness) per acre (8,821 t/m/ ha). For know n
and dependable areas , 1 ,500 st/ f t per acre (11 ,027 t/m/ha) may be
used. (Nelson, 1965)
acrea ge rent Roya lty or rent paid by the lessee for wo rkin g and dis-
posing of minerals at the rate of so much per acre,
acre -foot The quantity of wate r that wo uld cov er 1 acre, 1 ft deep (1
ha, 13.6 cm deep). One acre-foot contains 43,560 ft
3
).
acre-in ch The vol um e of water , soil , or other material that will cover
1 acre, 1 in deep (1 ha, 1.1 cm deep). (AGI, 1987)
acre -yield The average quantity of oil , gas, or wat er recovered from 1
acre (0.4 ha) of a reservoir. (AGI, 1987)
actet ic ac id amine
  acetamide.
acti nide A chemical element with atomic numb er greater than 88; all
are radioactive . Syn : actinidc element.
acti nide elem en t (a) One of the grou p of chem ical elemen ts of in-
creas ing atomic number , s tart ing with act inium (atomic number 89)
and extending through atomic number 103. These e lements occupy
one single place in the extended periodic table, in the same group into
which the rare-earth elements (lanthanides) are classified. See also:
actinide.
  (CCD , 1961; Gayn or, 1959) (b) One of the radioa ctive ele-
ments, atom ic numb ers 89 to 103. (Hurlbut , 1964)
actin olite A mon rclinic m ineral, 2[Ca2(Mg,Fe)5Sia022(0H)2] in the
hornblende ser ies Mg/(Mg+Fe
2+
) = 0.5 to 0.89 of the am phibo le grou p;
forms a series with tremolite; green, bladed, acicular, fibrous (byssolite
asbestos), or massive (nephrite jade); prismatic cleavage; in low-grade
metamorphic rocks . Syn:  actinote; strahlile.  Cf :  tremolite.
act inote  actinolite.
act ivated a lumina Highly porous, granular a lumin um oxide that pref-
erent ia l ly absorbs l iquids f rom gases and vapors , and moisture f rom
some liquids. (McGraw-Hill, 1994)
act ivated carbon Carbon, most ly of vegetable or ig in , and of h igh
adsorpt ive capaci ty . Syn:
  activated charcoal.
act ivated charcoal  activated carbon.
act ivated c lay A c lay whose adsorbent character or b leaching act ion
has been enhance d by treatment with acid. (CC D, 1961)
act ivated coal p low With a v iew to apply in g the coal p low to seams
too hard to be sheared by the normal cutt ing b lade, German mining
engineers have developed var ious types of power-operated cutters .
One consists o f a ser ies of compressed-air p icks mounted above each
other; another , o f a resonance pattern, houses two high-speed motors
eccentrically mounted and rotating in opposite directions. The latter
imparts a vibration to the cutting edge equivalent to 2,500 blows per
minute with a stroke of 3/16 to 1/4 in (4.8 to 6.4 mm) and a force of
app rox. 200 st (181 t). (Mason, 1951)
a c t i v a t e d p l o w  Huwood sliccr.
act ivat in g agent (a) A substance that whe n added to a mineral pulp
prom otes flotation in the presence of a collecting agent. Syn:  activator.
(BS, 1962) (b) Rea gent used particularly in differen tial mineral f lota-
tion to help cleanse the mineral surface so that a collector may adhere
to it and p ermit or aid its floatability. Freque ntly used to allow floa ting
mine rals that had been prev iously depr esse d. (Mitchell, 1950)
activ atio n (a) In the flotation proce ss of mine ral dressin g, the proce ss
of altering the surface of specific mineral particles in a mineral pulp to
prom ote adheren ce of certain reagen ts. (Pryor, 1963) (b) Th e chang-
ing of the pass ive surface of a metal to a chem ically activ e state. C f:
passivation.  (ASM , 1961) (c) In the flotation process of ore beneficia-
tion, the process of altering the surface of specific mineral particles in
an ore pulp to promote adheren ce of certain reagents. (Henderso n,
1953) (d) Th e proces s of mak ing a material radioac tive by bomba rd-
ment with neutrons, protons, or other nuclear particles. See also:  acti-
•vation
 analysis.
  (Lyman , 1964)
act ivat ion analys is A method for ident i f y ing and measuring the
chemical e lements in a sample to be analyzed. The sample i s fi rst made
radioa ct iveb y bomb ardment w ith neutrons, charged part ic les , or other
nuclear radiation. The newly radioact ive atoms in the sample g ive of f
characteristic nuclear radiations that can identify the atoms and indi-
cate their quan tity. See also: activation.  (Lym an, 1964)
activa tor (a) In flotation, a chem ical added to the pulp to increase the
floatability of a mineral in a froth or to refloat a depressed (sunk)
mineral. Also called activating reagent. (CTD, 1958) (b) A reagent
that affects the surface of minerals in such a way that it is easy for the
collector atoms to become attached. It has the opposite effect of a
depressor. Cf:  depressor.  (N ew ton , 1959) (c) A substance that is re-
quired in trace quantities to impart luminescence to certain crystals.
(CCD , 1961) (d) Ions that are photo n emitters. (Van Vlack, 1964) (e)
An y agent that causes activatio n. See also:  activating aqent.  (Bennett,
1962)
active agen t Surface -active substance that imm unizes solids against a
parting liquid. (Hess)
active earth pres sure The mini mu m valu e of lateral earth pressure
exerted by soil on a structure, occur ring w hen the soil is allowe d to yield
sufficiently to cause its internal shearing resistance along a potential
failure surface to be completely mobilized. See also:  surcharge.  Cf:
passive earth pressure.  (AGI, 1987)
active entry An entry in wh ich coal is being mined from a portion
thereof or from connec ted section s. (USBM, 1960)
act ive faul t One l iable to further movemen t . Cf :
  passive fault.
son, 1965)
active laye r (a) The surficial dep osit that under goes seasonal changes
of volume , swel l ing whe n frozen or wet , and shr inking when thawing
and drying. (AGI, 1987) (b) A surface layer of ground, above the
perma frost, that is froze n in the win ter and thaw ed in the summ er. Its
thickness ranges from sever al centimeter s to a few meters. (AGI, 1987)
active min ing area (a) The area , on and beneath land, used or dis-
turbed in activity related to the extraction, rem oval, or recovery of coal
from its natural deposits. This term exclude s coal preparation plants,
areas associated with coal preparation plants, and post-mining areas.
(SME, 1992) (b) Th e area in wh ich active mining takes place relative
also to extraction of me tal ores, industrial m inerals, and other minerals
of economic value ,
active wo rk in gs All places in a min e that are ventilated and inspected
regularly. (Federal Min e Safety , 1977)
activity (a) In nuclear phy sics, the rate of decay of atoms by radioac-
tivity. It is me asur ed in curie s. (Bennett, 1962) (b) T he ideal or ther-
modynamic concentration of a substance, the substitution of which for
the true conce ntration , permits th e application of the law of mass action.
See also: ionization constant.  (CT D, 1958)
actual age  absolute age.
actual bre aki ng stren gth The brea king load obtained from a tensile
test to destruction on a sample of rope. (Ham mon d, 1965)
actual hors epow er The horsepo wer real ly developed, as proved bv
trial. (Standard, 1964)
actual perform ance curve A performance curve showin g the results
actually obtained f rom a coal prepa ration treatment. (BS, 1962)
actuated roller sw itch A switc h placed in contact with the belt con-
veyo r imme diately prece ding the conve yor it is desired to control. In
the centrifugal sequence control switch, a driving pulley bears against
the driving belt; as the latter move s, the pulley rotates and the governo r
weights attached to the pulley shaft are flung out and so complete an
electrical pilot circuit and thus start the subsidiar y belt. (Nelson, 1965)
acut ebise ctrix (a) The line that bisects the acute angle of the optic axes
of biaxia l minera ls. (Fay, 1920) (b) The angle <90" betw een the optic
axes in a biaxial crystal, bxa.  C f :  optic angle.
adam antin e (a) Like the diam ond in luster. (Webster 3rd, 1966) (b)
Diam ond hard . A com merc ial name for chilled steel shot used in the
adamantine drill , which is a core-barrel type of rock-cutting drill with
a cutting edge fed by these shots. Cf: vitreous.  (Pryor, 1963)
adama ntine luster Diamo ndl ike luster . (Hurlbut , 1964)
a d a m e l l i t e  quartz monzonite.
adam ic earth A term used for com mo n clay, in reference to the mate-
rial of which A da m , the first man, was m ade; specif, a kind of red clav.
(AGI, 1987)
adam ite A rare hyd rou s zinc arsenate, Zn:(AsO,i)(OH), occurring
granular or in crusts and crystallizing in the orthorhombic system.
Weakly radioact ive; var iable co lor—yel lowish, greenish, or v io let ,
rarely colorless or white; found in the oxidized zone of zinc orebodies.
Associated with smithsonite, calcite, malachite, hemimorphite, l imo-
nite, and azurite. Small amou nts of uraniu m have been found in some
specim ens of adamite. (Fay, 1920; Cros by, 1955)
adam site A greenish-black mus covite found in a schist at Derb y, VT;
has been called mar garod ite. (Dana, 1914)
Ada m's sn uff box Hol low , roughly rectangular pebble l ined with goe-
thite; Lenh am beds, Netle y Hea th, Surrey , U.K. (Arkell, 1953)
ada mu d A condition ing material that may be adde d to drill ing mud
in order to obtain satisfactory cores and sam ples of formations. (Wil-
liams, 1964)
adap ter troug h A short section of a shaker conveyor trough that serves
as a connecting link betwee n any two sizes of trough. Oones, 1949)
added diamon ds As used by the diamond-bit manufactur ing indus-
try , the number or carat weight of new diamond s that must be added
to the reset table diam onds s a lvaged from a worn bi t in order to have
enou gh to set a new bit. (Long, 1960)
add itive A correction applie d to times of seismic reflections measure d
from an arbitrary time origin. The add itive is norma lly applied for the
purpose of translating the time origin to correspond to the datum
D
a d d l i n g s
elevation cho sen for compu tation , and it is algebraic in sign. (AG1,
1987)
ad dlin gs A term used in the northe rn and parts of other coalfields in
Great Britain to describe earn ings or wa ges . (Nelso n, 1965)
Ade l ine s tee lmak ing proces s A process of producing precis ion cast-
ings of steel or steel alloys, which comprises first forming the steel or
stee l a lloy in molten form b y the a luminoth ermic process , by igni t ing
a mixture of i ron ore and a luminum; then running the molten metal
into a mold prepared by packin g a refractory mold com posi t ion around
a model made of wax or other comparat ive ly low-melt ing-point sub-
stance and heat ing to melt out the wa x and con sol idate the mold; and
finally centrifu ging the mo ld. (Osbo rne, 1956)
adel i te (a) A n orthorhombic mineral , CaMg (As0.t)(0H ); occurs with
manganese ores, (b) The mineral group adelite, austinite, conichalc-
ite, duftite, and gabrielsonite.
  ozocerite.
adhesion (a) Th e molecular force holding together two di fferent sub-
stances that are in contact, as wa ter in the pore sp aces of a rock. Cf:
cohesion,  (b) Shearing resistance betw een soil and another material
under zero externa lly app lied pressur e. (ASC E, 1958) (c) In the flota-
tion process, the attachment of a particle to air-water interface or to a
bubble .
adh esiv e slate A very absorbe nt slate that adhe res to the tongue if
touched by it. (Standard, 1964)
adiabat ic ca lor imeter A ca lor imeter that pract ica l ly remains unaf-
fected by its surr oun ding s and neither gains nor loses heat. (Osborne,
1956)
adiabat ic comp ress ion Com pres s ion in which no heat i s added to or
subtracted from the air and the internal energy of the air is increased
by an amount equivalent to the external work done on the air. The
to increase the pressure on account of the decrease in volume a lone;
therefore , the pressure durin g adiab at ic com press ion r ises faster than
the volu me diminishes. (Lew is, 1964)
adiabat ic e f f ic i ency A compress ion term obtained by div iding the
pow er theoret ica l ly necessary to compress the gas and del iver i t wi th-
out loss of heat , by the power suppl ied to the fan or compressor
dr iveshaft .
adiabat ic expansion Expansion in wh ich no heat i s added to or sub-
tracted from the a ir , wh ich coo ls dur ing the expansion be cause of the
wo rk done by the air. (Lew is, 1964)
adiabat ic tempera ture The temperature that wo uld be at ta ined if no
heat were gained from or lost to the surro undin gs. (New ton, 1959)
adiabat ic temperature chang e The compress ion of a f lu id without
gain or loss to the surrounding s wh en wo rk is performe d on the system
and produ ces a rise of temp erature . In ver y deep w ater such a rise of
temperature occurs and must be conside red in the vert ica l temperature
distribution. (Hy , 1965)
adinole An argi l laceous sediment that has undergo ne a lbi t izat ion as
a resul t o f contact metamorphism along the margins of a sodium-rich
mafic intrusion. C f: spilosite; spotted slate.  (AGI , 1987)
adipi te An a luminosi l icate of ca lc ium, magn esium, and potass ium
having the composi t ion of chabazi te . (Dana, 1914)
adipocer i te
  a axis.
adit (a) A horizontal or near ly hor izontal passage dr iven from the
surface for the work ing or dew ater in g of a mine. I f dr iven through the
hill or mountain to the surface on the op pos ite side, it wo uld b e a tunnel.
Syn:
  (Lew is, 1964) (b) A s used in the
Colorado statutes, it may apply to a cut e ither open or undercov er , or
open in part and undercover in part , dependent on the nature of the
ground, (c) A passage driven into a mine from the side of a hill .
(Statistical Research Bureau, 1935)
adi t end The furthermost end or part of an adi t f rom i ts beginning or
the very p lace whe re the miners are work ing und ergroun d toward the
mine. (Hess)
adi t level Mine working s on a level with an adi t . See a lso: adit.  (Hess)
adjacent sea A sea adjacent to and connected with the oceans, but
semienclosed by land. The North Polar , Mediterranean, and Car ib-
bean Seas are examp les . Syn: marginal sea.  (AG I, 1987)
adjustm ent of error Meth od of d is tr ibut ing the revealed i rregular i t ies
over a series of results. (Pryor, 1963)
adjutage Noz zle or tube from which hydraul ic water i s d ischarged.
Syn:
  ajutage.
a d m i s s i o n  admittance.
adm ittanc e (a) In a crysta l structu re, substitu tion of a trace element
fo r a major e lement of h igher va lence ; e .g . , Li* for Mg
2
*. Admitted trace
elements general ly have a lower concentrat ion re lat ive to the major
element in the mineral than in the fluid from which the mineral crys-
tallized. Cf:  capture; camouflage.  S y n :  admission.  (AGI , 1987) (b) The
reciprocal of impedance or the ratio of complex current to voltage in a
linear circuit. (AGI , 1987)
a d v a n c i n g l o n g w a l l
adob e A f ine-grained, usual ly ca lcareous, hard-ba ked c layey deposi t
mixed with s i l t , usual ly forming as sheets in the centra l or lower parts
of desert bas ins , as in the playas of the southwe stern United States and
in the ar id parts of Mexico an d South Am erica . I t i s probab ly a win d-
blow n deposi t , a l though it i s o f ten rewo rked and redepo si ted by run-
ning wate r. (AGI , 1987)
adob e charge A mud-covered or unconf ined explos ive charge fi red in
contact with a rock surface witho ut the useof a borehole . Syn:
  bulldoze;
mudcapping.  (Atlas, 1987)
adob e f lat A generally narrow pla in formed by sheet f loo d deposi t ion
of f ine sandy c lay or adobe brought d ow n by an epheme ral s tream, and
having a smooth, hard surface (when dry) usual ly unmarked by s tream
channe ls. (AGI , 1987)
ado be shot Ord inar ily referred to as a dobe shot. A stick or part of a
st ick of dynamite is la id on the rock to be broken a