Modern Mining December 2016

MINING News

The Tschudi open-pit, heap leach, SX-EW operation near Tsumeb in northern Namibia. Its current capacity is 17 kt/a of LME Grade A copper cathode (photo: Weatherly International).

Tschudi gets back to nameplate capacity

ner which could be incrementally cash generative at current spot prices within six months of commencement, partially offsetting current care and maintenance costs being incurred at the sites. Ultimately it is envisaged that a period of up to two years may be required to develop the requisite improvements in underground mining operator skills and to train suffi- cient Namibians to the best international standard and fully realise the potential of Otjihase and Matchless. Under the proposal, small scale min- ing and campaign processing would be conducted by a small team in the first scheduled primary mining area at Otjihase. All of this mining would be conducted in ore and the programme would commence with the establishment of productive and safe primary mining systems. The current strategic goal envisaged for such a restart would be safe and sustainable production from the Otjihase concentra- tor of 10-12 kt/a of copper in concentrate at C1 unit costs of below US$2/lb. Due to the large amount of underground access infrastructure in place plus the fact that the Otjihase concentrator is well maintained and capable of treating up to 800 kt/a of ore, the capital expenditure required to deliver such an outcome is expected to be very low, and would likely rank as one of the lowest capital intensity copper produc- tion opportunities in the world. 

Namibian copper miner Weatherly International, listed on AIM, reports that its Tschudi project near Tsumeb in northern Namibia re-attained its nameplate pro- duction rate during October, two months earlier than forecast. In October the company repeated its Tschudi guidance from July that name- plate production rates of 1 417 tonnes per month (tpm) would be re-attained by December 2016, following the reduced production in the June and September 2016 quarters due to excessive groundwa- ter inflow to the pit. Weatherly has also updated on its potential Tschudi expansion to 20 kt/a, which it first announced in December 2015 when it said the expansion would require expenditure of US$1,2 million. Subsequent optimisation of the operating parameters used within the solvent extraction and electro-winning plants has now reduced this capital estimate to US$0,2 million. The company says the focus for the expansion opportunity evaluation has now shifted to evaluating mining, pad devel- opment, stacking, and leach scheduling paths to sustain such a potential expan- sion and quantifying potential operating cost savings from the expansion. Regarding its Otjihase and Matchless underground mines in the Windhoek area,

both in care and maintenance, Weatherly says the mineral resources at the mines plus the installed processing plant capac- ity present a valuable opportunity for the company. Success will be dependent on achieving higher production rates and lower unit costs than were achieved dur- ing the period from 2011 to 2015. This will be critically dependent on safer and more productive undergroundmining execution capability and operator skills development in this area is the critical requirement to unlock the opportunity. The company notes that the geol- ogy and processing characteristics of the Otjihase and Matchless orebodies are well understood and offtake agreements remain in place for the high-quality con- centrate which can be produced. While some further geological resource devel- opment work may be required over time, for example to upgrade the historical esti- mate at Old Matchless to a JORC mineral resource estimate and to upgrade and extend the Matchless Western Extension resource estimate down plunge, the criti- cal path to implementing a sustainable restart of operations lies with underground mining skills development. Weatherly says it has identifed a potential opportunity to commence a skills development programme in a man-

4  MODERN MINING  December 2016