Modern Mining October 2018

MINING News

Liqhobong produced 835 832 carats in FY 2018 compared to 365 891 carats in the prior year (photo: Firestone Diamonds).

Firestone Diamonds, listed on AIM, has released its final results for the year ended 30 June 2018 – representing the first full year of commercial production at its Liqhobong mine in Lesotho. According to the company, the year was marked by an “exceptional operational perfor- mance” which saw a 128 % increase in diamonds recovered to 835 832 carats, an 18 % increase in grade to 22 cpht, a 93 % increase in ore tonnes treated to 3,8 Mt and a 5 % decrease in operating costs to US$11,62 per tonne treated. The largest diamond recovered during Liqhobong delivers an “exceptional performance” the year (in September 2017) was a 134- carat gem quality light yellow diamond while the most valuable diamond recov- ered was a fancy pink diamond which realised a sale price of US$112 781 per carat. Revenue increased by 125 % to US$62,2 million and the loss for the year decreased by 91 % to US$14,2 million. The lower than expected frequency of valuable diamonds recovered and con- tinued low prices for the ROM category diamonds during the early part of the year resulted in lower than expected average diamond values achieved at sale, prompt-

ing a revision to the mine plan. The result was a shorter nine-year mine plan, which could be supported by a lower average diamond value of US$75 per carat, whilst retaining the optionality of taking advan- tage of the longer 14-year life of mine should realised diamond values increase or should there be a sustained improvement in market conditions. Liqhobong’s impeccable safety record was maintained throughout the 2018 financial year, reaching 6,2 million man hours worked without a single lost time injury at the end of the year. Firestone notes that the processing plant includes a conventional 3-stage crushing circuit which is designed to crush kimberlite and to liberate diamonds. “We do our best to minimise diamond damage; however, the recovery process is inher- ently abrasive and damage does occur as in all recovery plants to a greater or lesser extent,” says Firestone. “During the year, there was an increase in diamond damage which is assessed on all +5 carat stones recovered, which resulted in a thorough investigation into all possible areas where damage might occur within the plant. Pleasingly, the minor modifications made subsequently to certain parts of the plant and recovery areas resulted in a decrease in diamond damage to well within acceptable industry standards by the year end.” 

Zambia’s Munali nickel mine to restart in 2019 London-based Consolidated Nickel Mines (CNM) reports that it successfully concluded a transaction with Chinese-listed company Jinchuan in September 2018 to re-start the Munali nickel mine, located 75 km south of Lusaka in Zambia.

Working with the mine’s management team, CNM has spent the past two years conducting extensive evaluation and study work at Munali to put together a sustainable restart plan. A new geological model has been developed, a new JORC resource has been defined and a newminingmethod has been planned to extract the nickel from the orebody more efficiently and economically. Now fully funded for recommencement of operations in Q1 2019, CNM will produce its first nickel concentrate within that quar- ter. By Q3 2019, CNM says it will have met the production ramp up schedule, deliver- ing 60 000 tonnes of ore per month and 25 000 tonnes of nickel concentrate by the end of 2019. 

In excess of U$180 million has already been spent by the previous owners in developing the mine, installing a concentra- tor and bringing the mine into production. However, for a number of reasons, such as the use of the wrong geological model and hence the wrong mining method being employed, this led to uneconomic opera- tions when the nickel price fell, and the placing of the mine on care and mainte- nance at the end of 2011, says CNM.

6  MODERN MINING  October 2018