the evolution of block caving technology - ausimm …...... mining methods in underground mining,...
TRANSCRIPT
1
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.
3
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.
4
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.
8
Early Block Caving 1
Brinsmade,1911, public domain, courtesy of Hathi Trust
Pewabic mine, Michigan, USA,
longitudinal section
10
Early Block Caving 3
Stage 1
Stage 2
Pewabic mine, Michigan, USA
11
Early Block Caving 4
Stage 3
Stage 4
Pewabic mine, Michigan, USA
12
Early Block Caving 5
Stage 5
Stage 6
Pewabic mine, Michigan, USA
13
Early Block Caving 6
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.
14
Early Block Caving 7
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)
15
Early Block Caving 9
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
16
Stoddart, 1946, with permission from SME
Inspiration mine undercut level plan
Gravity Block Caving 2
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)
17
Stoddart, 1946, with permission from SME
Inspiration mine cross-section, in lowest section
of the orebody
Gravity Block Caving 3
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)
18
El Teniente mine, pillar undercutting
Gravity Block Caving 4
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
Gravity Block Caving 5
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.
20
Miami mine, shrink stopes and
pillar sublevel caving
Hardwick 1965, courtesy of SME
Gravity Block Caving 6
Miami mine, Arizona USA
• 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.
21
Miami mine, block caving a 45 m
panel across the orebody
Hardwick,1965, courtesy of SME
Gravity Block Caving 7
Miami mine, Arizona USA
• 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)
22
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
23
Julin et al, 1973, with permission from SME
Climax mine scraper block caving layout
Scraper Block Caving 2
Graphic
24
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
25
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
26
Conclusions
27
• 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
28
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?
29
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).
30
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).
31