Mason Coggin asks about block caving.
I have checked through the CD of contents of Mining Magazine, which covers
the period 1981 to 1998, and have found the following references to
articles describing mines which use the method ( I give the month/year/page
number);
USA
Magma Copper, San Manuel and Kalamazoo orebodies Apl 96, p247; Oct 94,
p186; Oct 92, p221
Questa molybdenum, Goat Hill May 84, p434
Chile
Andina Feb 95, 78; Sep 90, p142
El Teniente Mar 95, p142, Sep 90, p150
El Salvador Sep 90, p155
Philippines
Lutopan Mar 92, p136
Padcal Mar 92, p136
Indonesia
Ertsberg East Nov 84, p481
Japan
Tochibora Feb 92, p61; Nov 84, p387 (it uses other methods also)
RSA
Premier diamond mine Jan 96, p20 (stunning photo)
Palabora Jul 97, p28 (still open pit, but going underground)
Australia
Northparkes Aug 98, p57 (started up in 1997, the first use of block caving
in Australia).
Others, not featured in Mining Magazine during these years, include the
Zambian copper mines; Inco's Creighton mine; and Selebi-Phikwe.
I suspect that, worldwide, more ore is extracted using sub-level caving
than block caving, although as can be seen from the above list, block
caving is often used for low-grade copper ores.
Regarding surface subsidence over caving ( in this case sub-level caving )
I got a nice picture of surface collapse at Mantos Blancos. Chile in 1981 -
see Mining Magazine, December 1981, page 461. Being on the edge of the
Atacama Desert, there was no vegetation to hide what was happening.
Tony Brewis
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