Modern Mining November 2015

MINING News

In its quarterly activities report (to 30 September 2015), ASX-listed Mustang Resources, which holds the Save River diamond project in Mozambique, says “robust” gem-quality diamond recoveries continued during the reporting period. In 2014, Mustang acquired rights to earnmajority interests in the two diamond exploration licences in Mozambique mak­ ing up the Save River project. The project area comprises 24 000 ha and is situated in the Save River Valley, downstream from the well-known Murowa and Marange diamond fields in Zimbabwe. Mustang reports “robust”diamond recoveries at Save River Significantly, many of the known kim­ berlite pipes in Zimbabwe have been weathered away and the diamonds from the diamondiferous pipes have been washed down the river systems through the Save River. To date, Mustang has recov­ ered multiple gem-quality diamonds and considers that the project represents a robust opportunity to establish a large- scale alluvial diamond mining operation. In July and again in October, Mustang recovered 2,5-carat white diamonds from the shallow surface gravels at Save River. These are the largest diamonds to be recovered from the project to date. After the end of the quarter, Mustang announced the completion of the phase 1 exploration and bulk sampling programme at the project. The programme yielded 18 gem-quality diamonds from seven shallow trial pits. As of late October, a total of 47 dia­ monds totalling 30,28 carats had been recovered from bulk sampling activities, which – says Mustang – further reinforces its view that there is significant share­ holder value to be unlocked within the Save River project.

The company will continue to work towards defining a JORC-compliant min­ eral resource at Save River, while awaiting the results of drilling in order to determine the next priority targets for bulk sampling. Mustang is confident that with a new Flow Sort recovery unit now in place, and with the diamond recovery plant upgraded to operate at 1 000 tons per day (compared to 100 t/d previously), the recovery and quantity of diamonds will be significantly increased as the exploration and sampling programme is ramped up in the coming months.  than expected Rand exchange rate. The commissioning of the conveyors will now have a positive impact on reducing devel­ opment costs as trucks will no longer be used in decline development to the block cave level. Lace’s 220 t/h dense media separation plant operated efficiently on a batch basis during the reporting period, processing 5 825 tonnes of K6 and K4 kimberlite bulk samples extracted from the development tunnels. A 3-tonne bulk sample of the Lace kim­ berlites was despatched to Johannesburg for testing using one of the high volume optical/x-ray waste sorters DiamondCorp has been investigating. The test work was very positive, and demonstrated that the majority of the waste can be ejected ahead of the DMS processing plant. This technology, combined with the significant water savings generated from the instal­ lation of the de-grit circuit, means, says DiamondCorp, that there is potential for Lace to be mined at a faster rate than is currently planned. This will have a positive impact on mine economics and the NPV of future cashflows. 

The bulk sampling plant at the Save River diamond project (photo: Mustang Resources).

Lace to soon start its production ramp-up In its latest update on its Lace diamond mine near Kroonstad in the Free State, AIM-listed DiamondCorp says develop­ ment work in the Upper K4 (UK4) block is concentrating in kimberlite on the 310 m production level in preparation for produc­ tion ramp up to commence before the end of the year.

in a delay to the blasting of the slot drive from which the initial tonnage ramp up commences. This delay will result in cashflow pressure on the company’s 74 %-owned operating subsidiary, Lace Diamond Mines (Pty) Ltd, in Q1 2016 when debt repayments are due to commence. As a result, detailed discus­ sions have been held with the company’s primary lenders and BEE partners regarding options to alleviate cashflow pressures. The discussions have been positive and a formal request to continue interest roll-up of the Industrial Development Corporation loan until positive cashflow is achieved has been lodged. Management do not expect any issues with respect to being granted this request. Processing of K6 kimberlite and K4 kim­ berlite recovered from the production level drives and bulk test sites continued with further encouraging results. Development costs to date are averag­ ing R49 993 per metre against a budget of R38 280 per metre as a result of the chal­ lenges encountered, including a weaker

During September tunnelling activities advanced fromheavily diluted low-grade K6 kimberlite on the southern side of the kim­ berlite pipe into a transitional zone and then into higher-grade K4 kimberlite in the cen­ tre of the pipe. As a consequence, ground conditions improved and kimberlite devel­ opment rates exceeded the monthly call in October. Challenging ground conditions reported previously on the 290 m doming level have been overcome with the installation of steel arched sets which provide a safe canopy for employees and equipment from potential falls of ground. The void above the canopy is now being back-filled. However, the time taken to install the sets and make the area safe has resulted

12  MODERN MINING  November 2015