Modern Mining September 2017

TIN

necessitate – once work on the process plant starts – some fairly heavy loads being brought to site. Technically, Bisie will be a straightforward operation using mining and processing meth- ods which are widely used and well proven, as was detailed in the Definitive Feasibility Study (DFS), completed by MDM Engineering in col- laboration with Bara Consulting in early 2016 and updated in June 2016. The proposed mining method is Sub Level Caving (SLC) to remove the orebody in retreat fashion from the southern and northern limits of mineralisation back towards the centralised trucking ramp. Blasted ore will be loaded by 14-tonne capacity rubber-tyred LHDs dump- ing into 40-tonne articulated dump trucks and hauled to surface where it will be stockpiled ahead of processing for tin recovery. According to the recent Front End Engi­ neering Design (FEED) programme and associated Control Budget Estimate by DRA Projects, which gives the latest figures, ore will be delivered to the plant at a rate of 25 to 35 kt/month over an initial mine life of 150 months or 12,5 years. A cash margin of some US$11 040 per tonne of tin sold is fore- seen, yielding a LoM annual average EBITDA of approximately US$110 million (constant 2017 terms). The project has an NPV (8 %) of US$402,2 and an after-tax IRR of 49,1 %. The projected payback period is 17 months from the first tin production. These figures are based

of the informal tin mining boom in 2008/09. The introduction in the US in 2010 of the Dodd-Frank regulations (which, among other things, require manufacturers to audit their supply chains and report the use of conflict minerals), as well as the increasing difficulty of accessing the orebody using simple artisanal mining methods, had led to a sharp decrease in artisanal activity from around 2012 onwards. Said Robinson: “There are now only between 400 and 800 informal miners on site and – after discussions with the authorities – they are probably going to move.” All the miners left are located at the Mpama South deposit (which represents a future expansion of the project) and not the Mpama North orebody, which is where Alphamin will start mining. Ultimately, it is anticipated that the informal miners will move to legal artisanal mining sites which are currently being identified. Apart from artisanal activity, probably the single biggest challenge that Alphamin faced in its early days at Bisie was the sheer inaccessibil- ity of the site, which is located in mountainous, thickly forested terrain. Over the past year, the situation has improved dramatically with the construction of a 38-km access road. The ini- tial route was cleared using labour-intensive methods (up to 450 community members were employed) and several simple – but beautifully crafted – timber bridges were also erected. This initial track is now being upgraded to meet the demands of mine construction, which will

Another view of the boxcut. Its construction has now been completed on schedule.

September 2017  MODERN MINING  23