strategic minerals investigations 1941 - … states department of the interior harold l. ickes,...
TRANSCRIPT
UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary
GEOLOGICAL SURVEY W. C. Mendenhall, Director
Bulletin 931
STRATEGIC MINERALS INVESTIGATIONS1941
PART 1, A-J
Short papers and preliminary reports by
EUGENE CALLAGHAN, S. W. HOBBS, L. R. PAGE
and others
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1943
r:^ 1̂ HALL LIBRARy
CONTENTS
(The letters in parentheses preceding the titles are those used to designatethe papers for separate publication]
' * Page(A) Tungsten resources of the Blue Wing district, Lemhl
* County, Idaho, by Eugene Callaghan and D; M. Lemmon(published in June 1941)............................ 1
(B) Some quicksilver prospects in adjacent parts of Nev- "^ ada, California, and Oregon, by C. P. Ross (pub- ! lished in June 1941)................................ 23
(C) Tin deposit at Majuba Hill, Pershing County, Nevada, by W. C. Smith and V. P. Gianella (published in March 1942)......................................... 39
^ (D) Nickel-gold deposit near Mount Vernon, Skagit County, Washington, by S. W. Hobbs and W. T. Pecora (pub lished in January 1942)............................. 57
(E) Tungsten deposits in the Sierra Nevada near Bishop, California, a preliminary report, by D. M. Lemmon (published in March 1942)........................... 79
(P) Nickel deposits of Bohemia Basin and vicinity, Yakobi > Island, Alaska, by J. C. Reed and J. V. N. Dorr 2d
(published in May 1942)............................. 105(G) Chroiaite deposits of Kenal Peninsula, Alaska, by P. W.
' Guild (published in March 1942)..................... 139* (H) Tin and tungsten deposits at Silver Hill, Spokane
County, Washington, by L. R. Page (published in Au- , gust 1942)........................................... 177
'' (I) Nickel deposit near Riddle, Douglas County, Oregon, by W. T. .Pecora and S. W. Hobbs (published in March 1942)............................................... 205
(J) Quicksilver deposits in the Steens and Pueblo Moun tains , southern Oregon, by C. P. Ross (published in March 1942)........................................... 227
ILLUSTRATIONS
y - _________
r- PagePlajbe 1. Geologic map of productive part of the Blue Wing
_ district, Lemhi County, Idaho............ In pocket2. Level maps and sections of the Ima mine showing
A. geology................................... In pocket3. Longitudinal projections on vertical plane of
the Ima mine.................................. 204. Composite level map.of the Ima mine........ In pocket5. Maps of prospect tunnels, Ima mine.............. 20
"* "6. Index map of adjacent parts of Nevada, Califor nia, and Oregon, showing the location of the
* properties described.......................... 26
III
IV ILLUSTRATIONS
Page Plate 7. Geologic and topographic map of the principal
part of the Lone Pine district, Washoe County., Nev........................................... 26
8. Topographic sketch map of the Glass Buttes pros pect, Lake County, Oreg....................... 34 *
9. Geologic map and section of Majuba Hill,Nev....................................... In pocket ^
10. Geologic map and sections of the Majuba Hillmine................ *.................... In pocket >
11. Map showing location and geologic setting of theMount Vernon district......................... 60 ^
12. Geologic map and sections of Mount Vernonnickel-gold deposit........................... 60
13. Index map of southern California showing loca-tion of Bishop region and plate 14............ 82
14. Map of parts of the Bishop, Mt. Goddard, and Mt. Morrison quadrangles showing location of tung sten properties 0 ......»..o............... In pocket
15. Geologic map and section of the vicinity of PineCreek mine, Inyo County, Calif........... In pocket
16. Geologic map of the Pine Creek pendant..... In pocket17. Photograph showing the Pine Creek pendant on the t
north side of Pine Creek, Inyo County, Calif.. 9018. Geologic map of level A of the Pine Creek mine.. 9019. Geologic map and sections of the Tungstar mine.. 9820. Geologic and topographic map of Bohemia Basin
and vicinity, Yakobi Island, Alaska.... . In pocket21. Geologic and topographic map of the area sur
rounding the Tripod, Tunnel, Side Hill, and Muskeg sulfide-bearing bodies, Yakobi Islanu, Alaska........................................ 124
22. Geologic and topographic map of the area sur rounding the Takanls sulfide-bearing bodies, n- Yakobi Island, Alaska......................... 124
23. Geologic maps of prospect pits and tunnel in - sulfide-bearing bodies of Bohemia Basin and ^ vicinity, Yakobi Island, Alaska.......... In pocket
24. Geologic reconnaissance map of the southwesternpart of Kenai Peninsula, Alaska............... 142 >.
25. Geologic map of Claim Point, Kenai Peninsula,Alaska........................................ 150 ^
26. Geologic and topographic map of Red Mountain,Kenai Peninsula, Alaska.................. In pocket
27. Map showing mining claims at Red Mountain,Alaska........................................ 166
28. Plan and geologic map of the Star No. 4 orebody, Red Mountain, Alaska.................... 166
29. A, View, of Red Mountain, from the northwest; B, ** Banded ore 20 feet north of shaft, Star No. 4. 166
30. A, Banded disseminated ore, deposit No. 20, Red '"*'Mountain; B, Cnromite lens cut by fresh oliv- Tine dikelets, deposit No. 11, Claim Point..... 166 i
31. A, Drag fold in chromite, deposit No. 24, RedMountain; B, Drag fold, deposit No. 13, Red ^Mountain...................................... 166
32. Geologic map of Silver Hill, Spokane County,Wash,.................................... In pocket
33. Outcrop map of pegmatites in zone 1........ In pocket ^34. Geologic map of veins Nos. 1 and 2.............. 20055, Geologic map of vein No. 4...................... 20036. Geologic map of veins Nos. 5, 6, 7, and 8....... 200 <6*37. Geologic map of the vicinity of Nickel Mountain,
Douglas CoXinty, Oreg.......................... -20838. Topographic and geologic map of the nickel
deposit near Riddle, Douglas County, Oreg...., 208 ^ '
ILLUSTRATIONS V
Page Plate 39. Geologic sketch map of parts of the Steens and
Pueblo Mountains, Harney County, Oreg... In pocket 40. Geologic sketch map of the tunnel at the
Steens Mountain prospect..................... 250* 41. The lodes of the Fisher group.................. 250
42. Geologic and topographic map of the Lucky* - Strike group and adjacent ground............. 254
43. The lodes of the Mogul, Blair, and O'Keefe i, groups and adjacent ground................... 254
44o Geologic and topographic map of the Rabbit Holeand Red King prospects near Fields, Oreg..... 254
Figure 1. Index map of Idaho showing location of the BlueWing district................................ 3
2. Maps of prospect tunnels, General Electric- Miller group and Oompton claim............... 20
3. Geologic and topographic map of the Currier 1 mine, near Paisley, Lake County, Oreg........ 31
4. Index map showing location of Majuba Hill, Nev. 40 5 Generalized cross section of western end of
Mount Vernon district........................ 606. Vertical longitudinal section of the Mount Ver-
noh nickel-gold deposit...................... 727. Geologic sketch map of Round Valley Peak
* deposit...................................... 968. Geologic map of Hilton Creek deposit........... 989. Geologic map of the Pickup mine................ 101
10. Index map showing location of Bohemia Basin, v Yakobi Island, Alaska........................ 108
11. Index map of Alaska, showing area included inplate 24..................................... 140
12. Geologic map of Reef mine, Claim Point......... 15913. Geologic map of the Bluff No. 1 deposit, Claim
* Point........................................ 16114. Block diagram of deposit No. 5, Red Mountain... 16£
fc 15. Sketch map of Juneau No. 1 deposit, Red Moun tain. ........................................ 169
*i 16. Index map of Washington showing location ofSilver Hill, Spokane County.................. 178
^ 17. Geologic map of the walls and back of theinclined shaft in the pegmatite of zone 1.... 186
18. Geologic map of the tin-bearing pegmatite ofzone 1 on the 75-foot level.................. 196
19. Geologic map of vein No. 3..................... 19920. Index map showing location of the Riddle nickel.
deposit...................................... 20621. Diagrammatic sketch of a vertical section of
the mineral deposit at the Discovery work-* ings....:......,............................. 215
22. Composite and schematic profile of the south- ' * east side of Nickel Mountain and the adjacent
area, showing relationship of ore to topogra- j phy.......................................... 222
23. Index map of Oregon, showing the location of*k the Steens and Pueblo Mountains.............. 228
TABLES
Page Table 1. Assays of trench and drill-core samples from the
nickel-gold deposit near Mount Vernon. ......... 742. Analyses of representative nickel-bearing rocks.. 743. Results of flotation tests on sulfide-bearing
breccia. ....................................... 774. Results of flotation tests on silica-carbonate
rock.. ......................................... 77
A Page
Abstracts of reports............... 1, 23,39, 57, 79, 105, 139, 177, 205, 227
Acknowledgments for aid.............. 1-2,4, 24-25, 41, 59, 00, 106, -141-142, 179, 208, 229.
Adamson claims, features of. 91-92, pi. 15 Alaska, chrqmite deposits in......... 139-
175, pis. 24-31nickel deposits in 105-130, pis. 20-23
Antelope claims Nos. 1-10, featuresof........................ 25, pi. 7
Arizona mine, features of............ 257
B
Bishop, Calif., tungsten deposits 'near............. 79-104, pis. 13-19
Blalr claims, features of .252-254, pi. 43 Blue Boy claim, features of.......... 252-
253, pis. 42-43 Blue Bull group, features of....'.. 256-257Blue Wing district, Idaho, geology
of...................... 6-10, pi. 1tungsten resources of... 1-21, pis. 1-5
Bluff Ho. 1 ore body, features of 161-162 Bohemia Basin, Yakobi Island, Alaska,
field work in.................. 106geology of......... 109-117, pis. 20-22prospect pits in....... 132-130, pi. 23topography of.......... 107-109, pi. 20
Bureau of Mines, operations by... 179, 202
California, quicksilver deposits in 20-30 tungsten deposits in.............. 79-
104, pis. 13-19Callaghan, Eugene, and Lemmon, D. M.,-
Tungsten resources of the Blue Wing district, Lemhl County, Idaho................ 1-21, pis. 1-5
Carpenter and Brown prospect,features of.............. 95, pi. 16
Chipmunk mine. See Pickup nine. Chromlte deposits, Kenai Peninsula,
Alaska.......... 139-175, pis. 24-31Chromlte production, at Kenai Penin
sula, Alaska................... 141Chromite samples, analyses of........ 151,
158, 162-, 167, 170, 171, 174 Claim Point, Kenai Peninsula, Alaska,
chromite deposits at -156-162, pi. 25 ohromite reserves at.............. 158mining claims at.................. 157
Copper deposit, Majuba Hill, Nev.... 54-55Coyote Valley prospects, features of 103-
104 Crimson Rose claims, features of..... 253,
pi. 43 Currier mine, features of........... 30-33
Dorr, J. V. N., 2d, Reed, J; C., and,Nickel deposits of BohemiaBasin and vicinity, YakobiIsland, Alaska.. 105-138, pis. 20-23
Douglas County, Oreg., field work in 207nickel deposit in.. 205-226, pis. 37-30
P
Fisher group, features of 250-251, pi. 41
G
General ElectricrKiller mine, fea tures of...................... 19-21
General Electric Co., property of... 19-21
Page
Geologic maps:Blue Wing district, Lemhi County,
Idaho......................... pi. 1Bohemia Basin, Alaska........... pi. 20Kenai Peninsula, Alaska..... pis. 24-§6Lone Pine district, Washoe County,
Nev........................... pi. 7riajuba Hill, Nev................. pi. 9Mount Vernon district', Wash..... pi. 11Mount Vernon nickel-gold deposit,
Wash......................... pi. 12Pine Creek pendant, Inyo County,
Calif........................ pi. 16Silver Hill, Spokane County,
' Wash........................', pi. 32Steens and Pueblo Mountains,
Oreg......................... pi. 39Gianella, V. P., Smith, W. C., and,
Tin deposit at Majuba Hill, Pershing County, .Nev........... 39-
55, pis. 9-10Glass Buttes prospect, features of... 33*
36, pi. 8 Guild, P. W., Chromite deposits of
Kenai Peninsula, Alaska........ 139-175, pis. 24-31
H
Harney County, Oreg., quicksilverdeposits in................. 227-250
Hilton Creek prospect, features of.. 97-99Hobbs, 3. W., and Pecora, W. T.,
Nickel-gold deposit near Mount Vernon, Skagit County, Wash.... 57-
78, pis. 11-12Hobbs, S. W., Pecora, W. T., and,
Nickel deposit near Riddle, Douglas County, Oreg........... 205-
226, pis. 37-30Horse Heaven mines, Inc., operations
by............................. 249
Idaho, tungsten deposits in 1-21, pis. 1-5 Iina mine. Blue Wing district, Idaho,
history of development of...... 4-6tungsten production from.......... 4-6workings of............ 16-19, pis. 2-5
Ima Mines Corporation, operations by 5property of............ 16-19, pis. 2-5
Juneau Ho. 1 deposit, features of.... 169
K
Kenai Peninsula, Alaska, chromitedeposits in..... 139-175, pis. 24-31
field work in.................. 141-142geology of......... 142-150, pis. 24-26
Ledoux & Co., assays by.'............ 74-75Lenunon, D. M., Tungsten deposits in
the Sierra Nevada near Bishop,Calif............ 79-104, pis. 13-19
Lennon, D. M., Callaghan, Eugene,and, Tungsten resources of theBlue Wing district, LemhlCounty, Idaho........ 1-21, pis. 1-5
Lone Pine district, Washoe County,Nev., geology of....... 25-26, pi. 7
quicksilver deposits in 24-20, pis. 6-7 Lucky Strike group, features of...... 251-
254, pi. 42
VII
M Page
Majuta fault, features of... 48-49, pi. 10Majuba Hill, Hev., copper deposit at 54-55
geology of................ 41-47, pi. 9tin deposit at........ 39-54, pla. 9-10
Majuba Hill mine, workings of........ 47-48, pi. 10
Marquette, W. H., results of flota tion tests by................. 76-77
McGee Mountain prospect, features of 99-100
Millovitch prospect, features of..... 94-95, pi. 16
Mineral Dome prospect. See Rosa!mine.
Mogul group, features of.. 252-254, pi. 43 Mount Vernon district, Wash., field
work in........................ 59geology of.......... 60-64, pis. 11, 12history of mining in.............. 58
Muskeg bodies, features of 121-122, pi. 21
N
Nevada, copper deposit in........... 54-55tin deposit in........ 39-55, pis. 9-10quicksilver deposits In... 24-28, pi. 7
Nickel-gold deposit, Mount Vernon,Wash.............. 57-78, pis. 11-12
Nickel deposit, Riddle, Oreg......... 205-226, pis. 37-38
geology of............. 211-224, pi. 38Nickel deposits, Bohemia Basin,
Yakobl Island, Alaska.......... 105-138, pis. 20-23
history of development of......... 110Nickel Mountain, Dreg., analyses of
samples from..... 211, 213, 216, 220geology of......... 208-211, pis. 37-38
O'Keefe claims, features of.......... 252-254, pi. 43
Ore bodies, Silver Hill, SpokaneCounty, Wash................ 190-201
Ore deposits, Blue Wing district,Idaho......................... 10-16
Bohemia Basin, Yakobl Island,Alaska...................... 118-138
Kenai Peninsula, Alaska........ 150-154Lone Pine district, Washoe County,
Hev........................... 26-27Majuba Hill, Nov................. 49-55Mount Vernon, Mash............... .64-78Riddle, Oreg................... 211-224Sierra Nevada near Bishop, Calif.. 89-
104Steens and Pueblo Mountains, Oreg. 240-
258 Ore reserves, Blue Wing district,
Idaho.......................... 14-15Bohemia Basin, Yakobi Island,
Alaska...................... 127-132Kenai Peninsula, Alaska... 154-156, 166 Mount Vernon, Wash............... 71-78Riddle, Ores................... 224-226Sierra Nevada near Bishop, Calif.. 88-
89Silver Hill, Spokane County, Wash. 202-
203 Oregon, nickel deposit in............ 205-
226, pis. 37-38 quicksilver deposits in 30-36, 227-258
Pacific Nickel Co., operations by.... 50sampling by.................. 71,' 73-74
Page, Lincoln R., Tin and tungsten deposits at Silver Hill, Spokane County, Wash........... 177-
203, pis. 32-36 Pecora, M. T. ? and Hobbs, S. W.,
Nickel deposit near Riddle,Douglas County, Oreg........... 205-
226, pis. 37-38
Page
P.ecora, W. T., Hobbs, S. W., and,Nickel-gold deposit near Mount Vernon, Skagit County, Wash.... 57-
78, pis. 11-12 Pickup mine, features of.......... 100-102Pine Creek Canyon prospects, features
of............................ 92-93Pine Creek mine, workings of......... 89-
91, pis. 15, 16, 18 Pueblo and Steens Mountains, Oreg.,
quicksilver deposits In........ 227-258, pis. 39-44
Prospecting, suggestions for, at Ma juba Hill, Hev................ 53-54
in Blue Wing district, Idaho..... 15-16in Lone Pine district, Washoe
County, Nev................... 27-28
Quicksilver deposits, Steens andPueblo Mountains, Oreg......... 227-
258, pis. 39-44Quicksilver prospects in adjacent
parts of Nevada, California, and Oregon.......... 23-37, pis. 6-8
R
Rabbit Hole group, features of 256, pi. 44 Red Hawk mine, features of.......... 29-30Red King group, features of.......... 255-
256, pi. 44 Red Mountain, Kenai Peninsula,
Alaska,' chromlte deposits at... 163-175, pis. 26-31
chromite reserves at.............. 166mining claims at........... 165, pi. 27
Reed, J. C., and Dorr, J. V. N., 2d, Nickel deposits of Bohemia Basin and vicinity, Yakobi Is land, Alaska.... 105-138, pis. 20-23
Reef mine, features of............ 157-159Regal claims, features of......... 250-251Riddle, Oreg., nickel deposit at..... 205-
226, pis. 37-38 Riddle nickel deposit, history and
development of.............. 206-207Ross, C. P., Quicksilver deposits in
the Steens and Pueblo Moun tains, southern Oregon......... 227-
258, pis. 39-44 Some quicksilver prospects In
adjacent parts of Nevada, California, and Oregon......... 23-
37, pis. 6-8 Rossl mine, features of........... 102-103Round Valley Peak deposit, features
of............................ 96-97
Side Hill body, features of.......... 122-123, pi. 21
Sierra Nevada, near Bishop, Calif.,field work in.................. 80
geology of........... 82-88, pis. 15-16Silver Hill, Spokane County, Wash.,
field work in.................. 179geology of............. 179-190, pi. 32tin production from..............'. 178
Silver Hill pegmatites of zone 1,workings on..... 194-195, pis. 32-33
Silver Hill pegmatites of zone 2,workings on................. 195-196
Silver Hill pegmatites of zone 3,features of................. 196-197
Silver Hill pegmatites of zone 4,workings on.................... 197
Silvertown group, quicksilverdeposits of................... 28-29
Smith, W. C., and Gianella, V. P.,Tin deposit at Majuba Hill,Pershing County, Hev........... 39-
55, pla. 9-10 Spokane Tin Co., property of...... 177-178
INDEX
Page
Star No. 4 claim, features of........ 166-167, pi. 28
Steens Mountain prospect, featuresof.................. 249-250, pi. 40
Steens and Pueblo Mountains, Oreg.,field work in.................. 229
geology of............. 232-240, pi. 39quicksilver deposits in........... 227-
258, pis. 39-44 topography of.......... 230-231, pi. 39
Surprise group, features of.......... 255
Takanls bodies, features-of... 125, pi. 22 Tin and tungsten.deposits, Silver
Hill, Spokane County, Wash..... 177-203, pis. 32-36
Tin deposit, Majuba Hill, Nev........ 39-54, pis. 9-10
Tin production at Silver Hill, Wash.. 178 Tin-bearing pegmatites, Silver Hill,
.Wash, geology of....... 182-187, 191workings on........ 194-197, pis. 32-33
Tiptop claims. See McGee Mountainprospect.
Tripod bodies, features of 124-125, pi. 21 Tungstar mine, workings of.. 93-94, pi. 19 Tungsten deposits, near Bishop,
Calif.......................... 79-104, pis. 13-19
geology of........... 82-88, pis. 15-16
Page
Tungsten production, in Blue Wingdistrict, Idaho................ 4-6
In Sierra Nevada near Bishop,Calif......................... 81-82
Tungsten and tin deposits, Silver.Hill, Spokane County, Wash..... 177-
203, pis. 32-36Tungsten resources, Blue Wing dis
trict, Idaho......... 1-21, pis. 1-5Tungsten veins, Silver Hill, Wash.,
features of..... 197-201, pis. 34-36geology of........................ 187-
188, 191-192, pis. 34-36 Tunnel body, features of.. 123-124, pi. 21
U
U. S. Vanadium Corporation, propertyof.................... 89-91, pi. 18
W
Washington, nickel-gold deposit in... 57- 78, pis. 11-12
Works Progress Administration,sampling by............... 71, 73-74
Yakobi Island, Alaska, nickeldeposits....................... 105-
138, pis. 20-23
o509612 O - 43 - 2
UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary
GEOLOGICAL SURVEY W. C. Mendenhall, Director
Bulletin 931-A
TUNGSTEN RESOURCES OF THE
BLUE WING DISTRICT, LEMHI COUNTY
IDAHO
BY
EUGENE CALLAGHAN
AND
DWIGHT M. LEMMON
Strategic Minerals Investigations, 1941
(Pages 1-21)
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1941
For sale by the Superintendent of Documents, Washington, D. C. ....... Price 30 cents
CONTENTS
T Abstract...............................Introduction...........................Geologyo...............................
Sedimentary rocks..................Igneous rocks......................Struc ture..........................
Ore deposits...........................Mlneralogy0 ........................The veins..........................Origin.............................Localization of ore bodies.........Size and grade of ore bodies.......Re serve s...........................Suggestion for further exploration.
Mines and prospects....................Ima..........................General Electric-Miller mine, Other prospects..............
Page 1 16788
101012131314141516161921
ILLUSTRATIONS
Page Plate 1. Geologic map of productive part of the Blue
Wing district, Lemhi County, Idaho....... In pocket2. Level maps and sections of the Ima mine
showing geology.......................... In pocket3<, Longitudinal projections on vertical plane
of the Ima mine..................... ....... 204. Composite level map of the Ima mine........ In pocket5. Maps of prospect tunnels, Ima mine............ 20
Figure 1. Index map of Idaho showing location of theBlue Wing district.......................... 3
2. Maps of prospect tunnels, General Electric- Miller group, and Compton claim.............. 20
III
-*
TUNGSTEN RESOURCES OF THE BLUE WING DISTRICT,
LEMHI COUNTY, IDAHO
By Eugene Callaghan and Dwight M. Lemmon
ABSTRACT
The Blue Wing district, Lemhi County, Idaho, is not only the principal tungsten mining district in the State but it has re- cently become one of the leading producers of tungsten in the United States. So far only one mine In the district Is produc- tive, but other prospects are being actively developed.
The veins fill a complex group of fractures in quartzite of the Belt series near the border of a granite mass that does not crop out but is exposed in underground workings. The vein fill ing is mainly quartz, which encloses fluorite, orthoclase, rho- dochrosite, huebnerite, pyrite, tetrahedrite, molybdenite, and minor amounts of other minerals. The minerals other than quartz have a rough zonal arrangement with reference to the granite. The ore mined has an average content of about 0.72 percent of huebnerite (manganese tungstate). This mineral occurs mainly in the wider parts of the veins, and ore shoots are confined to the relatively large veins close to the granite. The more numerous minor veins farther away are not regarded as of much promise.
The Ima mine has thus far yielded roughly 175,000 tons of ore. An estimated 50,000 tons remains in sight above the lower or main level; and, although the veins probably pinch downward, there may be 40,000 tons more below the present workings. Some ore has been found on adjacent ground, but here and in outlying parts of the district the present development is not enough to permit estimates of reserves.
INTRODUCTION
The Blue Wing district, in southeastern Lemhi County, Idaho,
is the principal tungsten mining district In the State and in
recent years has become one of the leading producers in the
United States. The present report summarizes the results of an
examination of the district made by Eugene Callaghan, assisted
from Sept. 8 to 22, 1940, by Charles Vitaliano and from October
12 to November 5 by D. M. Lemmon, Donald Wyant, and James Pol-
locko
2 STRATEGIC MINERALS INVESTIGATIONS, 1941
The staffs of both the Ima Mines Corporation and the Incan- *
descent Lamp Department of the General Electric Co. cooperated _f
to further the work in every possible way. Both companies sup- ^
plied accommodations for the field party, as well as maps, re
ports, information, and actual help with the field work. Mr.
Wo P. Barton, general manager, Owen Hickey, mine superintendent,
Carl Dice, engineer and mill superintendent, and Floyd Harper,
bookkeeper, of the Ima Mines Corporation, and H. H. Barrows,
manager, tungsten mine division, Incandescent Lamp Department, Jl
and Ployd Elliot, superintendent, of the General Electric Co., ^*
deserve particular mention. ^
The district is on the west slope of the Lemhi Range (fig. 1) "*
in T. 14 N., R. 23 E. Its sole producing mine, the Ima, is in +
sec. 23 on the north side of Patterson Creek, a mile upstream
from the small settlement of Patterson, which is at the mouth of -><
the canyon and on the east side of Pahsimeroi Valley. Mackay,
the shipping point and the terminus of a branch of the Union ^
Pacific Railroad, is 56 miles distant via Double Springs Pass,
or 100 miles distant through Challls, the route used when Double
Springs Pass is closed by winter snows. Salmon, the county
seat, is 68 miles northwest of Patterson. Most of the roads be-W
tween these different points are graded and parts of some are ¥
paved.»i
The Lemhi Range, which has a northwesterly trend, reaches
altitudes of more than 11,000 feet, or more than 5,000 feet
above the broad Pahsimeroi Valley. In the vicinity of Patterson
the western slope of the range, up to an altitude of 8,000 or "*
9,000 feet, is remarkably smooth and even, with an average gra- -'-
dient of 25°, and is little dissected between the V-shaped major «
canyons. The sides of Patterson Canyon near the Ima mine have . :
an average gradient of 35°. Jutting cliffs rise in irregular .^,
succession on the canyon walls and are separated by steep shal- ^
low gulches, which contain long talus slides and have alluvial
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO
117" 116 115° 114° 113° 112° III
25 0 25 SO__ 75 IOOMILES
Figure 1. Index map of Idaho ahowlng the location of the Blue Wing district.
4 STRATEGIC MINERALS INVESTIGATIONS, 1941
cones at their mouths. The canyon bottom averages between 300
and 500 feet in widtho Patterson Creek and the other large
streams entering Pahsimeroi Valley have built huge alluvial fans
that reach nearly to the middle of the valley.
The Ima mine has been visited by several geologists and en
gineers. The deposit was described in some detail by Umpleby2/
and Livingston, and some facts regarding its minerals were re-3/
corded by Shannon. The mine has been mentioned briefly by4/Bell, and recent developments have been described by Barton and
5/Arentz. Development and production are briefly described in
the various chapters of Mineral Resources of the United States
from 1910 to the present and in the reports of the State Mine
Inspector of Idaho. An unpublished report on the Ima mine by
C. B. Pollock, of the American Smelting & Refining Co., illus
trated by detailed geologic maps and sections with assay fig
ures, and a report by Don Emigh on the reserves of the Ima mine
were made available to the writers of this paper.6/
According to Umpleby ~^ the veins in Patterson Canyon were
prospected for silver and gold as early as 1881, but their pre
cious-metal content was too low for profitable mining. Tungsten
was not discovered until 1903. In 1911 the first efforts were
made to recover tungsten at the Ima mine; a 50-ton concentration
mill was operated in 1912, and two shipments of concentrates
were made in 1913. At that time 2,000 feet of development work
had been done in all, on the upper and lower levels, and theI/
upper tunnel was 900 feet long. In 1914 J. Nolan leased the
I/ Umpleby, J. B., Geology and ore deposits of Lemhi County, Idaho: U. S. Geol. Survey Bull. 528, pp. 73-71*, 77, 79, 109-112, 1913.
2/ Livingston, D. C., Tungsten, cinnabar, manganese, molybdenum, and tin deposits of Idaho: Idaho Univ. Bull. 2, vol. lU, pp. 21-25, 1519.
V Shannon, E. V., Minerals of Idaho: U. S. Nat. Mus. Bull. 131, pp. U67-5bg, 1926.
U/ Bell, R. N., Idaho rare metals: Min. and Contracting Rev., vol. 37, no. ?7, p. 5, 1935.
%] Barton, W. P., and Arentz, S. S., Mining and milling tungsten at the Ima mine; Min. Gong. Jour., vol. 25» no. 8, pp. 16-19, August 1939-
6/ Umpleby, J. B., op. cit., p. 109.]J Livingston, D. C., op. cit., p. 21.
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 5
mine but sold his interest to Callahan and Duffield, who mined
tungsten with little success in both the upper and lower tunnels.
They in turn sold to Jeffs and Johnson, who sunk a 70-foot In
cline, near the entrance of the lower tunnel, from which they
are said to have recovered 8 tons of tungsten concentrate in one
month in 1916o Prom May 1917 until January 1918 the mine was
operated by Nolan and D. R. Wheelwright. In 1927 and 1928 some
work was done by the Patterson Mines Corporation under lease§/from the Ima Consolidated Mining & Milling Co., but the work
yielded only a small output.
In 1934 the Ima Mines Corporation took over the property and
produced 2,300 pounds of concentrates averaging 56 percent of
WO o During 1935 development work was actively carried on, but 3
there was no production. Late in 1936 about 800 tons of ore was
mined and milled, and production has continued to the present.
Late in 1939 and early in 1940 the American Smelting & Refining
Co. investigated the deposit both by geologic mapping and by di
amond drilling. The mill recently has been enlarged to treat
120 tons daily. The metallurgical treatment involves crushing,
jigging, and grinding to 35 mesh in a ball mill, followed by an
other jigging, flotation, and tabling of concentrates. The Jig
and table concentrates are dried and passed through a magnetic
separator to take out metallic iron and then huebnerite. The
remaining concentrates, which consist mainly of sulphides, are
shipped to the smelter, and the huebnerite concentrate, which
averages 67 percent of WO,, eventually reaches the incandescent-o
lamp plant of the General Electric Co. In the fall of 1940
there were 20 men employed in the mill and 40 in the mine 0
Sj Campbell, Stewart, Annual reports of the mining industry of Idaho for the years 1927 and 1928, pp. 160 and 15^, respectively.
303579 0 41-
STRATEGIC MINERALS INVESTIGATIONS, 1941
Recent production of the Ima mine ia given in the table be
low. The mill heads have averaged 0.55 percent of WO , or very3
roughly 0.72 percent of huebnerite, and of this the mill re
covers about 75 percent. The ore has an average content of 1.75
ounces of silver to the ton, of. which 80 percent is recovered in
the sulphide concentrates. The sulphide concentrates recovered
average 4 percent of the ore treated and contain about 42 ounces
of silver to the ton, 0.01 ounce of gold, 3.75 percent of copper,
7 percent of lead, 28 percent of iron, 5 percent of zinc, 37
percent of sulphur, 1 percent of lime, 12 percent of insolubles,
and 0.5 percent of W0g 0
The ore also contains a variable amount of molybdenite,
averaging about 0.08 percent, but at present this is not savedo
Recent production of the Ima mine
-\ Q-*7 '
1938..................... ......
1939...........................
1 QA() ~J
rPr*'+'0 1
Huebnerite Concentrate (pounds)
174,800
077 noo
ZQQ OOP
360,177
1,210,805
Percentwo3
66.54
£z a i n
67»00
Sulphide Concentrate (pounds)
667.4
1,356.0
1,431.0
1,215.0
4 CCQ A
Includes 16,000 pounds of huebnerite produced in November and December 19367
2/ For 10 months, January to October.
In December 1938 the General Electric Co<> purchased some
claims from W. E. Miller and staked additional claims. This
ground has been actively prospected since March 1940.
GEOLOGY
The areal geology of the Blue Wing district shown on plate 1
is simple. The exposed rocks are pre-Cambrian quartzites of the
Belt series. These are rather gently folded, the main fold
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 7
being an anticline of northwesterly trend, traversed by the can
yon of Patterson Creek. No igneous rocks are exposed within the
area shown on plate 1, but granite has been reached in the work
ings of the Ima mine and small masses of quartz diorite and oth
er granitic rocks crop out in neighboring parts of the Lemhi
Range. The fracture system that controlled the distribution of
the veins is very complex in detailo The Ima vein zone has a
northwesterly trend, apparently parallel to the trend of the
arch in the quartzite, and is closely associated with the gran
ite.
Sedimentary rocks<.--The Belt rocks in the district were all
formed by the metamorphism of somewhat feldspathic sandstones
and shales. They mostly consist of beds of micaceous quartzite
6 inches to 2 feet thick alternating with thin slaty layers.
Some of the quartzite beds are finely laminated, and some show
cross lamination. The rocks are in general brownish to greenish
gray on weathered surfaces but light greenish gray to black
where fresh. Because of their micaceous character and numerous
minor fractures, the rocks break down where weathered more read
ily than most quartzite rocks. Within the mapped area the rocks
are uniform in character and lack beds of sufficiently distinc
tive appearance to be used as markers. In other parts of the
Lemhi Range these same quartzitic rocks locally contain lenses
of purple, maroon, and white to pinkish quartzite, especially in
the upper part of the unite
These rocks have a cleavage, which in most parts of the map
ped area is parallel to the bedding, but in some places the an
gle between the two is 20° to 30°. Closely spaced shear planes
have locally obliterated the bedding, and in a few places there
are small drag folds of about 10-foot radius. Near faults and
vein zones the bedding is obliterated in much of the hackly
structure of the rocks. Most of the metamorphism in the Belt
rocks is regional and antedates the intrusion of the granite
8 STRATEGIC MINERALS INVESTIGATIONS, 1941
and the formation of the veins, but in a zone a few Inches wide
on the granite borders fine-grained biotite has been developed
in the quartzite.
Igneous rocks* The only igneous rocks visible within the
mapped area are the granite, and the small pegmatite veins that
locally accompany it, on and near the intermediate and lower
levels of the Ima mine, more than 300 feet beneath the surface.
The granite is pink and consists largely of orthoclase, with
abundant quartz, some plagioclase, a little biotite, and proba
bly some muscovite. All the granite so far revealed in the mine
workings contains quartz veinlets and disseminated sulphides and
fluorite. The orthoclase and quartz seem to have been unaffect
ed by the mineralization, but the plagioclase has been largely
.replaced by sericite and fluorite.
As shown on the maps of the intermediate and lower levels
(pi. 2) and as revealed in the adjacent stopes and raises, the
contact of the granite with the quartzite is very irregular.
Its average dip between the two levels is about 30° S., and
drill cores indicate that its dip beneath the lower level is 18°
S. The position of this contact with reference to the veins is
of economic importance, as the ore shoots thus far mined have
terminated at or near the contact.
Structure. The major folds in the Belt rocks of the Lemhi9/
Range trend nearly north. This fact was noted by Ross in an
earlier study of parts of the range farther north and east, and
he has confirmed this fact by more recent unpublished studies of
12/ an area closer to the Blue Wing district. Within the area here
mapped most of the dips observed between the Ima mine and the
front of the range are southwesterly, whereas east of this area
most of the dips are northeasterly,. Outcrops in the district
2/ Ross, C. P., The copper deposits near Salmon, Idaho: U. S. Geol. Sur vey Bull. 77^, P. 11, 1925.
10/ Ross, C. P., oral communication.
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 9
are not sufficient to define the structure clearly, but there
seems to be a local warp or arch in the mapped, area, with its
axial plane parallel to the vein system.
The fracture system as revealed in the underground workings
and by the distribution of veins on the surface is extremely
complex. The premineral fractures that determined the course of
the veins strike in general N. 20°-40° W. and dip about 60° W.
One productive vein,'however, at the east portal of the lower
adit of the Ima mine strikes N. 42° W. and dips 35° NE. Some
veins, moreover, strike northeastward, and dip either to the
northwest or to the southeast, but none of these have thus far
shown promise of being productive. At a few places on the sur
face these "cross" veins were observed to curve into the north
westerly system. The outcrop of the westward-dipping vein zone
along the steep canyon slope trends about N. 10° W. Where the
bedding strikes northwestward, the veins tend to follow the bed
ding. Such a bedding vein on the Mazda No. 28 claim of the Gen
eral Electric-Miller group yielded a small shipment of ore.
In addition to the veins and the gouge seams that follow
them, there are nearly flat or gently dipping fractures some of
which are premineral and some postmlneral. Examples of premin
eral fractures were observed in the long east crosscut -on the
lower level of the Ima mine, where a vertical vein between two
nearly flat fractures had narrower but uncrushed continuations
in the flat fractures. The vein is displaced, on the other hand,
by eastward-trending faults, the hanging walls of which are
shifted toward the west. These faults dip gently to the north,
as shown especially well on the upper level of the Ima mine.
The northern end of the upper part of the ore shoot on the Ima
mine intermediate level has been moved 32 feet to the southeast,
as indicated by the offset of the granite contact. These ob
servations, taken together, Indicate that such of the premin-
. eral fractures as were favorable in position arid attitude were
10 STRATEGIC MINERALS INVESTIGATIONS, 1941 .
mineralized and the others were not, and that there have been '
some relatively minor displacements since the vein was formed.
The fractures followed by the veins, as well as the veins
themselves, must have been formed later than the granite intru
sion, for no dikes of granite or other rocks follow the trend of
the vein system. It is thought that the fractures result from
disturbances during the closing stages of the granitic intrusion,,
ORE DEPOSITS
The tungsten ore bodies thus far found in the Blue Wing dis
trict are limited to the workings of the Ima mine, except that
exploratory work on the General Electric-Miller group has yield
ed enough ore for a test shipment. Only two small vein segments
were exposed at the surface on the Ima ground, and these pinched
out toward the northwest; the ore shoots opened in the past few
years were found by underground exploration. Huebnerite, the
tungstate of manganese, is the only mineral of economic impor
tance in the district. The silver, copper, and lead minerals
that first attracted the attention of prospectors have not
proved sufficiently abundant to be mined alone, although they
are valuable byproducts. The ore shoots in the Ima have been
large; the few shoots mined have yielded roughly 175,000 tons,
and 50,000 tons more is in sight above the lower level.
Mineralogy. The ore deposits are all quartz veins with
varying amounts of fluorite, orthoclase, and rhodochrosite as
the principal associated gangue minerals, and huebnerite, py-
rite, tetrahedrite, chalcopyrite, bornite, galena, sphalerite,
molybdenite, and scheelite as the principal metal-bearing miner
als. Weathering of the veins yields limonite pseudomorphous
after pyrite, together with azurlte, malachite, manganese ox
ides, cerargyrite, jarosite, molybdite, sulphur crystals, and
possibly other secondary products.
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 11
Fluorite, both greenish and purple, is the next most abun
dant gangue mineral after quartz. It is prominent only in a
zone extending 600 feet from the granite contact on the inter
mediate level, where it seems to bear a definite zonal relation
to the granite. Rhodochrosite, the most abundant carbonate, oc-.
curs at rather widely spaced intervals throughout the veins but
seems less abundant near the granite than at a distance from it.
Siderite appears in the concentrates, and other carbonates occur
in minute seams and vugs. Flesh-colored orthoclase occurs in
the veins near the granite contact, and scattered grains of it
have been found in veins at the surface. Micaceous aggregates,
apparently composed mainly of sericite, are present in many of
the veins, especially near the granite.
Pyrite is the most abundant of the metallic minerals. It
commonly forms cubical crystals, some of which are more than
half an inch in diameter. This mineral contains very little
silver and almost no gold.
Huebnerite is probably the second most abundant metallic
mineral in the ore. It is very widely though sparsely distrib
uted. The ore sent to the mill has an average content of only
0.72 percent of huebnerite, and in large quantities of vein
quartz the huebnerite is far less abundant. The mineral forms
reddish-brown prismatic crystals that in some specimens are more
than an inch long and average about a quarter of an inch in
width. Some of it is so soft and easily powdered that its re
covery in the mill is very difficult. Analyses of the huebner
ite from the district, listed by Shannon, 'show that it con
tains about 76<,3 percent of tungsten trioxide, 21.5 percent of
manganese oxide, and 2.2 percent of ferrous oxide. Scheelite,
the calcium tungstate, is present in very minor amounts, chiefly
in the veins near the granite. It is also scattered through the
ll/ Shannon, E. V., The minerals of Idaho: U. S. Nat. Mus. Bull. 131,P. U5g, 1926.
12 STRATEGIC MINERALS INVESTIGATIONS, 1941
mineralized granite, but so sparsely that it has no commercial .+
value.; -
Tetrahedrlte, the sulphantimonate of copper, is the most .^
valuable and probably also the most abundant mineral after hueb-
nerite. It contains most of the copper and practically all of
the silver produced (see p. 6). It forms irregularly dissemi-4
nated grains and masses closely associated with pyrite and with
minor amounts of chalcopyrlte and bornite. Galena and sphaler
ite occur in very small grainso Molybdenite (molybdenum sul
phide) is disseminated in small grains in the granite, but it
occurs chiefly in veins in or near the granite, most typically
in sheets on fracture and shear planes, possibly sheared out "\
from its original position in veinlets where its easy cleavage -.;.
and softness has facilitated movement.
The secondary minerals, chiefly formed from the weathering -
of pyrite and tetrahedrite, are of no economic importance. Man
ganese oxides probably were formed from rhodochrosite or some _,
other manganese-bearing carbonate, or perhaps in part from hueb-
nerite, although huebnerite does not readily decompose, for it
has been found intact in places where the sulphides have been
completely oxidized.
The veins. The Blue Wing district contains a complex systemi1-,
of quartz veins, many of which are small and lenticular. Explo
ration has shown that a few of these, grouped close to the bor-'ig,
ders of the granite, are relatively large. At greater distances.^
from the granite the veins are more numerous but much smaller j
and less continuous. The original complexity of the vein system -f
has been somewhat increased by minor postmineral faults.
Most of the vein quartz contains metallic minerals, but it -4'
is only in a few ore shoots, most of which were discovered re- «
cently, that the huebnerite is abundant enough to be valuable. ^
In places the sulphides, the carbonates, and huebnerite have aI
banded arrangement; elsewhere they are distributed at random '
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 13
through the quartz. Fluorite occurs very irregularly in large
grains and aggregates. As noted above, there is a tendency to a
zonal arrangement of some of the vein minerals with respect to
the granite. Fluorite, molybdenite, and scheellte, for example,
are relatively abundant close to the contact, and rhodochrosite
is more abundant at a distance.
Locally fractures in the vein quartz are lined with micace
ous minerals, apparently derived from the quartzlte, and there
are some relatively large micaceous aggregates within the quartz
veins. Here and there angular fragments of the wall rock are
included in the veins. Some of these seem more micaceous than
the unaltered rock, as though .part of the quartz had been re
moved.
Origin. The huebnerite-bearing quartz veins are believed to
have been formed by the filling of fractures that opened during
the final stages of the intrusion of the granite, mainly in the
quartzite adjacent to granite but also in the outer parts of the
intrusive mass itself. The solutions that formed the veins fol
lowed openings outward from the core of the magma body and fill
ed them with the vein minerals. They also soaked out through
the previously consolidated border and left such minerals as
fluorite, pyrite, sericite, and molybdenite disseminated through
the granite. These replaced some of the earlier magmatic miner
als, chiefly plagioclase. Evidence of the close genetic rela
tion of the mineralized material to this particular body of
granite is afforded by the fact that the principal filled frac
tures are close to the granite and that certain of the vein min
erals within and near the granite have a zonal distribution.
Localization of ore bodies. The sizes and shapes of the
veins were determined by the character of the openings available
at the time of deposition. As noted below, the grade of ore in
creases in proportion to the width of the veins, so that the ore
shoots are confined to the larger parts of the veins. The
14 . STRATEGIC MINERALS INVESTIGATIONS, 1941
arrangement of the veins, described on page 12, appears to show
that distention of the quartzite by heat late in the course of
intrusion, followed by contraction on cooling, resulted in the
forming of a few large fractures close to the granite mass and
more numerous smaller ones farther away. Thus the valuable ore
shoots are confined to the quartzite within a few hundred feet
of the granite.
Size and grade of ore bodies. All the known ore shoots are
in the larger veins of the Ima mine. As shown on plates 2 and 3,
the ore shoots on the main level are all in a stretch that ex
tends 1,200 feet from the K. C. Li tunnel junction to the last
ore shoot in the granite. The slope distance from this level to
the top of the productive zone is 90 feet at the northwest end
of the mine, 175 feet at the 10B2 raise, 250 feet at the 201
raise, and 300 feet from the K. C. Li tunnel junction to the
highest stope on the surface. There are many pinches and swells.
The maximum length of a stope without a pinch is 250 feet. The
stopes above the lower level reach a maximum height of about 175
feet without a pinch. The shapes of the veins are shown by the
section (pi. 2); in vertical section as well as in plan they
show pinches and swells, and in the 10B2 vein is a wide roll
where the thickness of the vein normal to the wall is 35 fee.t.
According to Mr. Dice, the wide parts of the veins tend to be
richer than the narrow parts. Near the top of the productive
zone in the Bungalow 2 stope the vein averaged only 0.2 percent
of WO.,, whereas from the 10A1 to the 10B1 the stopes averaged
1 percent.
Reserves. The known reserves of blocked-out ore and proba
ble ore are limited to the workings of the Ima mine. According
to Mr. Dice, the stopes above the lower level still contain
50,000 tons of blocked-out ore, the average grade of which is
probably about the same as that of the ore previously mined--
0»55 percent of WO.,.
TUNGSTEN,_BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 15
The probable ore, amounting to 40,000 tons, lies below the
lower level. This level, which shows much thinning and pinching
of the main vein, is evidently in the lower and narrowing part
of the productive zone., It is perhaps liberal, therefore, to
estimate that the probable ore body below the level in the main
vein has a length of 1,000 feet, a thickness of 5 feet, and a
- depth of 100 feeto The depth is estimated from the results of
diamond drilling, which Indicates that the granite slopes 18°
SEo and lies 300 feet below the lower level at the K. C. Li tun
nel junction, so that it probably does not cut off the produc
tive zone less than 100 feet below the level.
The west vein is so discontinuous or lenticular that no re
liable estimate of its quantity of minable ore seems possible.
It should be explored by conservatively placed crosscuts from a
level 100 feet lower.
A shoot of ore may remain in the so-called Talmadge vein,
which is exposed near the east portal on the lower level. Ex
ploration of this vein may open up another shoot with an addi
tional 50,000 tons of possible ore.
These estimates, totalling 90,000 tons of probable and pos
sible ore, should not be expanded until justified by further ex
ploration.
A little ore is exposed on the General Electric claims, but
this ground has not been much explored and has not yet been
proved to contain any appreciable tonnage of probable or possi
ble ore»
Suggestion for further exploration. The Ima Mines Corpora
tion plans immediately to run another level 100 feet below what
is now the lowest level in order to block out the remaining ore
in the lower part of the shoot. A drift extending southeast
ward, on this same new level, to determine whether another ore
shoot continues below and south of Patterson Creek is also
planned. This would necessitate drifting 450 feet to the south-
16 STRATEGIC MINERALS INVESTIGATIONS, 1941
east end of the present productive zone and driving 500 feet
further to reach the area below the creek. Such work., with ap
propriately spaced crosscuts, should suffice to determine the
possible extent of the ore shoots. Probably one or two diamond-
drill holes ought to be sunk on the south bank of the creek be
fore driving on this lower level. The work done thus far above
the creek level on the south side of the canyon has not yielded
results encouraging enough to warrant its being extended farther
until the exploration below the creek level is completed.
The General Electric Co. plans to test its property with
diamond-drill holes, placing the first holes near the Ima ground;
and by correlating the results of this drilling with the infor
mation on surface and underground conditions already available
the company hopes to locate the granite contact and ore shoots
to the northwest. If the results of this work prove encourag
ing, other holes wil] be put down farther northwest.
The small veins and short lenses exposed on the surface have
been pretty well explored, and all appear to be discontinuous
and of low grade. They seemingly justify little further explo
ration.
The work done in the Blue Wing district was limited to the
area shown on plate 1, and the possibility that deposits of
huebnerite exist in other parts of the Lemhi Range was not
eliminated. There are numerous quartz veins in the parts of the
range that surround the area here described, and some of them
are somewhat similar mineralogically to those on the Ima ground.
MINES AND PROSPECTS
Ima,, The Ima Mines Corporation holds 21 patented claims and
15 unpatented claims in sections 13, 14, 23, and 24, T. 14 N.,
R. 23 Eo The company, which is purchasing the property from the
previous owner, is at present carrying on exploration, develop
ment, mining, and milling. Many veins crop out on the property,
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 17
but production has all been obtained from a single set of veins
that have been extensively explored and mined.
The geologic map (pi, 1) shows the relation of the mine
workings and vein outcrops to the topographic and geologic fea
tures of the district; and the geologic maps of the levels and
the geologic sections (pis. 2 and 3) show the principal features
of the vein system, which, except for a few small shoots in
granite, is wholly in the bedded and partly metamorphosed
quartz!tes of the Belt series. The Ima mine has three levels
(pi. 4), connected by raises and stopes, with drifts and cross
cuts totalling 10,016 feet. The original portal of the main, or
lower, level enters the steep canyon slope a few feet above the
creek at an assumed altitude of 6,294 feet. The K. C. Li tunnel
now affords a second entrance to this level. The upper adit is
200 feet higher. An intermediate level, roughly halfway between
the other two, does not reach the surface. The upper level en
ters the mountain on the outcrop of the main productive vein
zone, but a large part of its 2,265 feet of drifts and cross
cuts is included in a long crosscut to explore veins that crop
out to the east of this main zone. The main tunnel level con
sists of 5,266 feet of drifts and crosscuts, which explore one
vein zone for 350 feet, near the surface, and another for 1,200
feet. The total distance from the portal to the face is 1,700
feet. The intermediate level has 2,485 feet of drifts and
crosscuts. Practically no work has been done below the lower
levelo
One principal vein has been explored and mined throughout
its length on all three levels. A second vein, which has been
less productive, lies from 40 to 140 feet west of the main vein
and appears on both the intermediate and the lower level. Just
above the lower level the main vein assumes a gentler dip and is
dropped to the east by a normal fault, so that it appears on
this level as two veins, a west segment and an east segmento
18 STRATEGIC MINERALS INVESTIGATIONS, 1941
The down-faulted segment probably does not extend far below the
levelo The general strike of the vein zone on the lower level
is northwest and its average dip 60° W. The veins pinch and
swell along the levels as well as up the raises, and in places
they are wavy in cross section. Faults that strike N. 70° E.
and dip 30°-70° No on the upper level offset the veins from 10
to 100 feet southwestward.
The sizes and shapes of the ore bodies, the grade of the ore
in them, their mineralogy, and other features have already been
described (see pp. 10-15).
On the surface above the productive part of the vein system
is the outcrop of a zone, roughly 100 feet wide and extending
northward from the upper adit for 1,500 feet, of branching and
unconnected vein lenses mainly less than 100 feet long and 3
feet wide. Some of these lenses contain a little huebnerite and
sulphides. Raises above the productive ore shoots show a simi
lar network of small veins. Most of these veins strike No 20°-
60° Wo and dip 35°-70° SW., but their outcrops on the steep
slope trend more nearly northward, as shown on the map. About
400 feet ea.st of the main vein on the upper level is another
vein zone that joins the first zone 800 feet above the upper
tunnelo It also consists of small discontinuous veins, and the
two crosscuts below this zone do not reveal any ore shoot, nor
do they give promise of any. Two short drifts (Talmadge and
lower Talmadge tunnels, pi. 5) show the nature of the veins in
the Ima No. 9 claim. Still farther east is a parallel zone of
small veins mainly dipping at angles of about 30° W. and showing
a little huebnerite at an inclined shaft. A vertical vein
(plo 5) in the Ima No. 6 claim, trending N. 35° W. is explored
by a drift 95 feet long. It is displaced at the base of the
tunnel by a longitudinal fault dipping 30° SW. A vein in the
Noo 3 claim (pi. 5) is explored for 130 feet by a tunnel on the
south side of the canyon. Another vein on the south side of the
TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 19
canyon on the Ima No. 10 claim, opposite the Ima mine, trends N.
35° W. at the outcrop, which is 7 feet wide, but a crosscut be
low (pi. 5) revealed only a small unproductive vein. The Boise-
Ellis tunnel in the Ima No. 1 claim follows a 2.5-foot vein that
strikes N. 23° W. and dips 72° SW., samples from which contain
virtually no tungsten. The tunnel in the Ima No. 2 claim shows
a small vein striking N« 23° W. and dipping 75° SE. In the Ima
No. 8 claim two cuts and a 40-foot incline shaft for a length of
200 feet expose a 2-foot vein that strikes N. 60° Eo and dips
40° NW.
Nearby, in the Ima No. 14 claim, is another vein striking N.
18° W. and dipping 51° SW. It is 1.5 feet wide and contains a
little huebnerite and tetrahedrite. A group of small veins in
the Ima No. 19 claim follows the bedding, which strikes N. 15°-
30° W. and dips 11°-20° SW.
General Electric-Miller mine. The General Electric Co. has
acquired 48 lode claims northwest of the Ima Mines Corporation
ground. Those surveyed for patent, totalling 24, are shown on
plate 1. Ground for a mlllsite and for water rights has been
acquired near Patterson.
Only an experimental shipment of 40 tons of ore, taken from
a prospect pit in the Mazda No. 28 claim, has thus far been pro
duced on this property. This ore came from a bedding vein, ex
posed in a large pit, which strikes northwest and dips about 30°
SWo A tunnel nearby shows a 2-foot vein, probably the same one,
striking N. 40° W. and dipping irregularly 25° SW. (fig. 2)
A short tunnel (figo 2) below the twin shafts shows a vein
containing much manganese and copper stain and some huebnerite.
The vein strikes N. 33° W. and dips 80° NE. A lower crosscut
(fig. 2) shows no vein, and the quartzite is very slightly dis
turbed.
GEOLOGICAL SURVEY BULLETIN 931 PLATE 3
NW.SE.
UPPER LEVEL
INTERMEDIATE LEVEL
J * nMAIN LEVEL
PROJECTION ALONG EAST SPLIT OF MAIN VEIN
NW
MAIN LEVEL
PROJECTION ALONG WEST SPLIT OF MAIN VEIN
NW.
SE.
MAIN LEVEL
PROJECTION ALONG WEST VEIN
0 50 250 Feet __I Prepared by Carl Dice, of Ima Mines Corporation
LONGITUDINAL PROJECTIONS OF THE IMA MINEU.S. GOVERNMENT PRINTING OFFICE : 1941 O-303S79
GEOLOGICAL SURVEY
7'quartz
Sheared zone with many Quartz veinlers
TALMADGE TUNNEL Ima No.Qclaim
Shear zone
I'quartz
Sheared zone with many quartz veinlets
^^§>.70°.
LOWER TALMADGE TUNNEL Ima No.9 claim
BULLETIN 931 PLATE 5
3
SECTION
IMA No.6 CLAIM TUNNEL
N
A
2'quartz
Adit timbered and logged
Manganese stain but no huebnerite or sulphides.Quartz
ab^ crushed
lYz quartz with copper stain Shaft to surface caved. 4'barren quartz in face
IMA No.3 CLAIM TUNNEL
EXPLANATION
Fault
Vein±30°
Strike and dip
Vertical
BOISE ELLIS TUNNEL Ima No.I claim
4 quartz
6-10 quartz
.. No sulphides
QuartziteWinze 10'deep on 8" vein
8"quartz-%;V2"vein follows AT bedding
IMA No. IO CLAIM TUNNEL0
IMA No.2 CLAIM'TUNNEL 1OO Feet
MAPS OF PROSPECT TUNNELS, IMA MINEU.S. GOVERNMENT PRINTING OFFICE : 1941 O-303579
21
On the slope above the Ima mine in Patterson No. 2 claim are
a long trench and a short tunnel showing several bedding veins
mostly less than 1 foot wide and dipping gently to the southwest.
The Cowboy tunnel in Mazda No. 13 claim reaches two veins at
right angles to each other 120 feet from the portal Two pits
immediately above show the same or similar veins. The larger
vein is 1 foot wide, strikes'N. 80° E., and dips 62° NW. The
smaller strikes N. 20° W. and dips 60° SW» A short tunnel and a
pit on the south side of the gulch northeast of the cabins in
the Mazda No. 6 claim show a 1-foot vein striking N. 45° W. and
dipping 50° SWo
Several other small veins have been prospected to a slight
extent on the property.
The company is actively exploring the Mazda No. 20 and Pat
terson No. 2 claims by means of trenches and by a crosscut tun
nel, now 700 feet long, starting in the Mazda No. 33 claim and
aiming N. 50° E. for the mineralized ground on Mazda No. 20,
which will be reached at a depth of 650 feet. Diamond drilling
is also contemplated. Numerous pits and tunnels excavated on
the property by earlier prospectors reveal several small veins,
some of which contain huebnerite.
Other prospects. Alex Compton holds some claims.on the
north side of Patterson Canyon, east of the Ima ground 0 A small
vein containing huebnerite has been followed for 48 feet by a
small drift trending N» 10° W.
Huebnerite occurs in vein-quartz float on the Rosebud claims
on the northwest edge of the mapped area, beyond the General
Electric ground. The vein has not been found in place, although
several pits and a short adit have been dug in search of it.
O
The use of the subjoined mailing label to return
this report will be official business, and nopostage stamps will be required
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
PENALTY FOR PRIVATE USE TO AVOID PAYMENT OF POSTAGE. $300
OFFICIAL BUSINESS
This label can be used only for returning official publications. The address must not be changed.
GEOLOGICAL SURVEY,
WASHINGTON, D. C