Modern Mining July 2015

COUNTRY FOCUS – BOTSWANA

three times the silver grade of other announced resources for the Kalahari Copperbelt. Mahumo is presently in the Scoping Study stage. MOD’s South African consultants – led by Nikolas Rhodes of Ridgeback Mining Services – are awaiting indicative underground mining costs from mining contractors and are reviewing a range of options before finalising the study. Initial underground models indicate that steady state production of up to 40 000 tonnes/ month ore mined over a 4-5 year mine life from Stage One is achievable. A combination of two underground min- ing methods is being evaluated to generate the best potential return from the Mahumo deposit. These include fully mechanised mining to establish two access declines, install develop- ment headings and to open up stopes to initiate production. Mechanised mining is proposed to convert to conventional mining operations (utilising airlegs for sub-level development and stope drilling) to achieve steady state ore production. Conventional mining methods are widely used in steeply dipping vein style deposits (similar to Mahumo) in Southern Africa and at significantly lower cost if compared with similar style Australian operations. There are several benefits of using conventional mining which include the fact that a large part of mine development is in ore (rather than in footwall waste) and reduced ore dilution. Due to the 2,4 km length of the Mahumo deposit, two declines are proposed to be accessed from two shallow open pits or box- cuts sited in near surface, high grade copper/ silver sulphide ore at each end of the deposit (providing potential for early revenue from Mahumo). More detailed mine design work and scheduling scenarios are required to con- firm this and will be further evaluated as part of the proposed PFS. The scoping level metallurgical test work is

now complete and has delivered exceptional copper recoveries of up to 96,6 % Cu on deeper sulphide ores. Commenting on the results recently, MOD’s Steve McGhee said: “First pass test work on a relatively deep bornite rich composite (from 196,6 m to 524 m depth) has yielded an excellent response to flotation with copper and silver recoveries of 96,6% and 85,9% respectively into a low mass concen- trate grading 38,5 % Cu and 758 g/t Ag. This complements the outstanding results already achieved with a shallower chalcocite rich com- posite. Future test work will aim to increase the silver recovery for bornite rich ores.” While Cupric Canyon is likely to be next mine developer in the Kalahari Copperbelt (it is planning to start construction of Khoemacau in 2016 and is expecting to be in production in late 2017 or early 2018), MOD Resources, based on the developments outlined above, looks well placed to follow in its footsteps, subject of course to the pre-feasibility and feasibility

High-grade copper/silver concentrate produced during the test work pro- gramme.

studies proving positive. Photos courtesy of MOD Resources

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July 2015  MODERN MINING  39