the evolution of block caving technology - ausimm …...... mining methods in underground mining,...

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The Evolution of

Block Caving

Technology Tony Weston MAusIMM(CP)

MassMin 2016 Image: Turton, 1952, with permission from SME

Caving Methods

• Top slicing

• Sublevel caving

• Block caving

• Open stoping with mass

blasting of pillars and draw

under cave.

2 Hensley, 1973 with permission from SME

Typical gravity block cave at Miami mine,

Arizona, USA

Block Caving 1

The term block caving is used in this

presentation as a name for the

mining method where a small

portion of a block or orebody, the

undercut, is drilled and blasted, and

induces caving in the remainder of

the block or orebody. It includes

panel caving, as a subset and

sequencing variant of block caving.

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Ray mine, Arizona, USA

Blackner, 1915, with permission from SME

Block Caving 2

Block caving can be divided into various types according to the method

for lateral transfer of the ore from the drawpoints to a crusher or haulage

system:

• Early block caving – a mixture of methods leading to gravity block

caving.

• Gravity block caving – transfer through a grizzly and inclined raises

with some early examples using small scale rail haulage. Includes

some hybrid methods.

• Scraper block caving – scraper (slusher) winch and hoe.

• Load haul dump (LHD) block caving – current technology using

mainly diesel powered units.

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Current Block Caving Practice

Graphic

Image: Atlas Copco, 2011 with permission from Atlas Copco 5

Load haul dump

(LHD) block caving:

• Undercut level

• Extraction level

• Haulage level

• Originated in England.

• Michigan, USA iron ore

mines.

• Western USA copper

mines.

• Slices of ore were mined

using timbering in

broken ground.

• After slice was mined

timber was blasted down

and caving induced.

6 Image: Jackson,1932, courtesy of SME

Top Slicing 1

Horizontal top slicing

• Labour intensive.

• Large user of timber.

(Lewis, 1941)

7 Jackson,1932, courtesy SME

Top Slicing 2

Inclined top slicing at Coronado mine, Arizona, USA.

Pewabic mine, Michigan, USA,

1890s, mining hematite iron ore.

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Early Block Caving 1

Brinsmade,1911, public domain, courtesy of Hathi Trust

Pewabic mine, Michigan, USA,

longitudinal section

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Stage 1

Stage 2

Pewabic mine, Michigan, USA

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Stage 3

Stage 4


12


Stage 5

Stage 6


13


Stage 7

Stage 8

Ohio Copper mine, Utah, USA

• Blocks 30 m square, with an

initial height of 9 m, later

increased to 18 m.

• Combined undercut and

extraction level.

• Inclined ore passes, with

approximately 150 per block.

• Undercut level developed,

and drilled and blasted.

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Schmidt, 1915, public domain, courtesy of Hathi Trust

Section showing representative ore

passes at Ohio Copper mine.

Ohio Copper mine, Utah, USA

• Rises for ore passes

developed to just below the

undercut level.

• Last round in the rises broken

through to the undercut after

the undercut was blasted.

• Draw controlled at the grizzly

on the level below.

(Schmidt, 1915)

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Schmidt, 1915, public domain, courtesy of Hathi Trust

Cross section of undercut drilling

at Ohio Copper mine

Gravity Block Caving 1

Inspiration mine, Arizona, USA

• Copper mine on the same ore

deposit as the Miami mine.

• Based on the mining method

used at the Ohio Copper.

• Physical modelling of the design

performed using large box and

small rocks.

• Commenced production in 1915

• Block 30 m square in plan.

Inspiration mine, Arizona,

USA

undercut level plan

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Stoddart, 1946, with permission from SME

Inspiration mine undercut level plan


Inspiration mine, Arizona, USA

• Separate undercut, grizzly

and haulage levels.

• High labour and supply costs

for underground mining after

World War 2.

• Open pit mining commenced

in 1948 in areas previously

planned for block caving.

(Parsons, 1933; Parsons, 1957; Stoddart, 1946;

Weed, 1950)

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Stoddart, 1946, with permission from SME

Inspiration mine cross-section, in lowest section

of the orebody


Image: Webb and Skinner, 1932, courtesy of SME

El Teniente (previously Braden) mine,

Chile:

• Production started in 1906 with

glory holes from surface and then

shrink stoping.

• Pillars between parallel shrink

stopes undercut and drawn down

under cave.

• Later adopted gravity block caving.

• LHD block caving commenced in

early 1980s.

(Webb and Skinner, 1932; Ovalle and Albornoz, 1981;

Turton, 1952)

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El Teniente mine, pillar undercutting


Turton, 1952, with permission of SME 19

El Teniente, drawing ore at a grizzly

level, circa 1952 El Teniente, ore haulage, circa

1952

Turton, 1952, with permission of SME


Miami mine, Arizona USA

• Production commenced in

1911.

• A variety of mining methods

used prior to block caving.

• Square set stoping

• Top slicing.

• Shrink stoping with sublevel

caving of pillars.

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Miami mine, shrink stopes and

pillar sublevel caving

Hardwick 1965, courtesy of SME



• Transition to block caving

(with transfer levels in

place of grizzlies).

• Block caving of the whole

orebody performed but

unsuccessful.

• Block caving of panels 45

m wide across the

orebody with two

intermediate transfer

levels.

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Miami mine, block caving a 45 m

panel across the orebody

Hardwick,1965, courtesy of SME



• Gravity block cave 45 m by 90 m in

plan with a height of 90 m or more.

Flat draw over the area of the block.

• Includes boundary weakening.

• Blocks later reduced to 45 m square

in plan.

• Limited use of scraper block caving.

• Block caving was suspended in

1959.

(Hardwick, 1965 ; Hensley, 1973)

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Miami mine, 45 m by 90 m block

Hensley, 1973 with permission from SME

Scraper Block Caving 1

Climax mine, Colorado, USA, scraper

block caving:

• A molybdenum mine.

• More competent orebody resulted

in larger fragments, more hangups

and secondary breaking in gravity

block caves.

• A scraper (slusher) winch pulled a

large hoe to load rail wagons.

• The scraper block caving system

was used from the mid 1930s to

replace gravity block caving.

(Julin et al, 1973: Henderson, 1944; Bucky, 1945)

Graphic

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Julin et al, 1973, with permission from SME

Climax mine scraper block caving layout

Scraper Block Caving 2

Graphic

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Henderson, 1944, with permission from SME

Climax mine scraper drive Climax mine scraper winch

Henderson, 1944, with permission from SME

LHD Block Caving 1

Henderson mine, Colorado, USA:

• Henderson is a molybdenum mine

which commenced production in

1976.

• LHD block cave with continuous

panel caving designed as such from

its inception.

• Drawpoint configuration was initially

an offset herringbone shown in the

drawing but later changed to a ‘Z’

shape.

Henderson mine initial drawpoint

configuration Doepken, 1982, with permission from SME

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LHD Block Caving 2

Henderson mine, Colorado, USA:

• The drawbells were initially designed

with a vertical slot and rings blasting

from either side.

• Later changed to a layout without a

vertical slot and with all the

blastholes drilled from the undercut

level.

Henderson mine drawbell and undercut

blasthole drilling layouts

Doepken, 1982, with permission from SME

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Conclusions

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• Older mining methods such as top slicing and shrink

stoping were important precursors to block caving.

• Hybrid methods provided a springboard for the adoption of

block caving.

• The separation of the undercutting, draw and haulage unit

operations was important in the success of early block

caving.

• The detailed design of block caves depended on local

conditions, and previous mining practice.

• Increasing depth and ore competence drove changes in

the block caving method.

Acknowledgements

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The assistance of the Society for

Mining, Metallurgy and Exploration

(SME) in providing drawings and

photographs for this presentation and

paper is gratefully acknowledged.

Ray mine, Arizona, haulage drive

showing chutes and heavy timbering.

Blackner, 1915, with permission of SME

Questions?

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References 1

Atlas Copco, 2011, Mining methods in underground mining, Atlas Copco Rock Drills AB, CD format, 9851 6296 01k

Blackner, L A, 1915. Underground mining systems of Ray Consolidated Copper Co, in Transactions of the American Institute of Mining Engineers,

pp 1249–1290 (American Institute of Mining Engineers: New York).

Brinsmade, R B, 1911. Mining Without Timber, pp 194–195 (McGraw- Hill: New York).

Brown, E F, 1898. System of mining ore bodies of uniform grade, in Proceedings Lake Superior Mining Institute, Vol 5, pp 40–45 (Lake Superior

Mining Institute: Ishpeming).

Doepken, W G, 1982, The Henderson mine, in Underground mining methods handbook, (Hustrulid ed), 1982, pp 990-997 (Society for Mining,

Metallurgy, and Exploration, Littleton, Colorado).

Henderson, R, 1944, A comparison between the chute and grizzly system and the slusher system at the Climax mine, Transactions, pp 198-214 (

American Institute of Mining, Metallurgical, and Petroleum Engineers, New York).

Hensley, J H, 1925. Mining methods of the Miami Copper Co, Trans Am Inst Min and Met Eng, 72:78–99 (American Institute of Mining Engineers:

New York).

Hensley, J H, Young, G W and McLennan, F W, updated by Fletcher, J B, 1973. Miami Copper, Arizona, in SME Mining Engineering

Handbook, first edition, vol 1, pp 12-181 to 12-188 (The Society for Mining, Metallurgy, and Exploration Inc: New York).

Jackson, C F, 1931, Mining by the top-slicing method, with some notes on sublevel caving, Information Circular IC 6410 (United States Bureau of

Mines: Washington DC).

Julin, D E and Tobin, R L, 1973. Block caving, in SME Mining Engineering Handbook, first edition, vol 1, pp 12–162 to 12–222 (Society of Mining

Engineers of The American Institute of Mining, Metallurgical, and Petroleum Engineers Inc: New York).

Julin, D E, Smith, A K, Ohmert, E L and other Climax staff, 1973. Climax caving system, in SME Mining Engineering Handbook, first edition, vol 1,

pp 12–188 to 12–195 (Society of Mining Engineers of The American Institute of Mining, Metallurgical, and Petroleum Engineers Inc: New York).

Lehman, 1916. Ore drawing tests and the resulting method of Inspiration Consolidated Copper Co, Trans Am Inst Min and Met Eng, Sep, pp

1501–1514 (American Institute of Mining Engineers: New York).

Lewis, R S, 1941. Elements of Mining, second edition, pp 282–287 (Wiley: New York).

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References 2

MacLennan, F W, 1930. Miami Copper Company Method of Mining Low-grade Orebody, Technical Publication No 314, 44 pp (The American

Institute of Mining and Metallurgical Engineers: New York).

Ovalle, A W and Albornoz, H R, 1981. Block-caving with LHD equipment at El Teniente, in Design and Operation of Caving and Sublevel Stoping

Mines, pp 355–361 (Society for Mining, Metallurgy, and Exploration Inc: New York)

Parsons, A B, 1926. Who produced the world’s copper in 1925?, Engineering and Mining Journal-Press, 22 May, pp 869–870 (McGraw-Hill: New

York).

Parsons, A B, 1933. The Porphyry Coppers (American Institute of Mining and Metallurgical Engineers: New York).

Parsons, A B, 1957. The Porphyry Coppers in 1956, (American Institute of Mining, Metallurgical and Petroleum Engineers: New York).

Peele, R, 1941. Mining Engineers’ Handbook, vol 1, pp 10–360 (Wiley: New York).

Schmidt, F S, 1915. Caving system at the Ohio Copper mine, Mining and Scientific Press, vol 110, March 6, pp 361–364.

Stoddard, A C, 1946. History and development of block caving at the mines of the Inspiration Consolidated Copper Company, AIME Transactions,

pp 96–120 (American Institute of Mining Engineers: New York)

Turton, F E, 1952, Mining operations at the Teniente mine of the Braden Copper Company, Rancagua, Chile, Mining Engineering, June, pp 573-

577, American Institute of Mining Engineers: New York).

Vink, D M, 1998. From green field site to block cave mine – results of Northparke’s drill and blast design process, in Proceedings Seventh

Underground Operators’ Conference, pp 149–161 (The Australasian Institute of Mining and Metallurgy: Melbourne)

Webb, J S and Skinner, T W, 1932. Mining methods and costs at the Braden Copper Co’s mines, Sewell, Chile, Information Circular IC 6565

(United States Bureau of Mines: Washington DC).

Wightman, R H, 1946. A new caving procedure at the Crestmore limestone mine, AIME Transactions, pp 215–244 (AIME: New

York).

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