Engineering & Mining Journal

JUL 2014

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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1,700 million mt, albeit at about twice the copper grade. Modeling Assistance Last September, Dassault Systèmes Geovia issued a white paper detailing the use of its PCBC software for calculating mineable reserves in block-caving opera- tions. The company pointed out that this package, developed by Gemcom, has been in use for 25 years now, during which time it has been used for a wide variety of block-cave scenarios. The author of the monograph, Dr. Tony Diering, vice-president of Geovia's caving business unit, explained that the "pecu- liarities" of block-cave mining can make ore-reserve estimation more complicated. The orebody geometry, mining geometry, material fragmentation and flow, econom- ics and mining history, and sequencing can all have an effect, as can the impact of dilution from various sources. In situations where a new lift is being designed beneath an existing block cave, there is the possi- bility that resources may be increased through the presence of residual ore from the level above, and Dr. Diering is of the opinion that the quantification and catego- rization of this type of material will play a more important role in the future. Diering and Nat Burgio from Strata- vision in Australia co-authored a paper on the use of PCBC software for modeling the Ridgeway Deeps block cave, which they presented at the MassMin 2008 confer- ence in Luleå, Sweden. With the trend toward the establishment of block caves at greater depths over relatively small foot- prints and in competent rock-mass envi- ronments, they noted that operators are also planning higher cave columns in order to maximize the profitability from the extraction level. The ability for a cave to propagate vertically in such environments is less predictable, they added. With its production level at a depth of 1,050 m, Newcrest Mining developed Ridgeway Deeps beneath the existing sub- level caving mine. The transition took place in 2009, although as a 2012 analysis note from Credit Suisse suggested, the move here did not go completely to plan. "The caving rate and fragmentation is in line with modeled projections. How- ever, extraction, materials handling, second- ary breaking and crusher design appear to have assumed materially finer fragmenta- tion than is currently being achieved or was projected," the analysts commented. "Significant additions to the loader and sec- ondary breaking fleet have been required, adding unforeseen extraction costs." Nonetheless, Newcrest was not de- terred but has transferred the experience gained to the design of its newest operation in New South Wales, Cadia East. Officially opened in May, at a cost of A$2 billion, Cadia East is the first panel cave operation in Australia, and in due course will become the country's largest underground metal mine. In addition to learning from Ridgeway, Newcrest also sought technical expertise in block and panel caving from other world players, including Codelco and Rio Tinto's Northparkes. As the Credit Suisse report noted, "Ridgeway was very much the early prototype cave for Newcrest and has clear- ly shown what should not be repeated and what can be improved." Panel Cave 1 at Cadia East came on stream in January 2013, with Panel 2 34 E&MJ; • JULY 2014 www.e-mj.com B LO C K C A V I N G Atlas Copco supplied two Scooptram ST14s for autonomous operating trials at Codelco's Andina mine during 2012. The World's Block- and Panel-cave Mines Operation . . . . . . . . . . . . Company . . . . . . . . . . . . . . Location Diamonds Argyle . . . . . . . . . . . . . . Rio Tinto . . . . . . . . . . . . . . Northern Territory, Australia Cullinan . . . . . . . . . . . . . Petra Diamonds . . . . . . . . . South Africa Finsch . . . . . . . . . . . . . . Petra Diamonds . . . . . . . . . South Africa Kimberley . . . . . . . . . . . . Petra Diamonds . . . . . . . . . South Africa Copper Andina . . . . . . . . . . . . . . Codelco . . . . . . . . . . . . . . . Chile DOZ . . . . . . . . . . . . . . . . FCX . . . . . . . . . . . . . . . . . . Indonesia El Teniente . . . . . . . . . . . Codelco . . . . . . . . . . . . . . . Chile Northparkes . . . . . . . . . . China Molybdenum . . . . . . . NSW, Australia Padcal . . . . . . . . . . . . . . Philex . . . . . . . . . . . . . . . . Philippines Palabora . . . . . . . . . . . . . Palabora . . . . . . . . . . . . . . . South Africa Ridgeway Deeps . . . . . . . Newcrest Mining . . . . . . . . . NSW, Australia Salvador . . . . . . . . . . . . . Codelco . . . . . . . . . . . . . . . Chile Tongkuangyu . . . . . . . . . . Shanxi Zhongtiaoshan . . . . . Shanxi, China . . . . . . . . . . . . . . . . . . . Nonferrous Metals Molybdenum Henderson . . . . . . . . . . . FCX . . . . . . . . . . . . . . . . . . Colorado, USA Gold Cadia East . . . . . . . . . . . Newcrest Mining . . . . . . . . . NSW, Australia New Afton . . . . . . . . . . . New Gold . . . . . . . . . . . . . . British Columbia, Canada Asbestos Shabani* . . . . . . . . . . . . Zimbabwe State . . . . . . . . . Zimbabwe * C urrently mothballed over ownership issues EMJ_pg32-37_EMJ_pg32-37 7/2/14 8:35 AM Page 34

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