Design, build and operate project companies Evolve Mining and AMC have an approach to mine development and operation that is attracting attention. Evolve Mining designs for the lowest cost per tonne and AMC then mines at the guaranteed cost per tonne. Evolve is headed by Trevor Garden and Graham Mitchell-Innes and AMC by Warwick Hughes and Matthew Hughes. The firms combine innovative alternative mining solutions with traditional mining solutions; starting small, they improve on early-stage operational experience while generating cash flow, which is exceedingly advantageous for junior mining companies. More substantial capital expenditure (capex) is committed only after factual insight has been gained. All the while, a guaranteed cost per tonne lowers risk, and built-in flexibility enables mines to match output as commodity prices ebb and flow. Manganese mining companies that engage the services of Evolve Mining and AMC include Australia-listed Jupiter Mining, which has the Tshipi Borwa manganese mine, in the Northern Cape; United Manganese of Kalahari (UMK), which mines close to Hotazel, also in the Northern Cape; and Sebilo Resources, a majority black-owned mining company involved in the manganese mining sector. At this year’s Investing in African Mining Indaba, held in Cape Town, in February, Evolve Mining and AMC attracted attention by publicising a case study of an iron-ore mine in Sierra Leone, West Africa. Lightning-speed provision of multistage cash-generating plants by the two companies paved the way for the realisation of a massively lower cost per tonne – $2.20/t – compared with the original $9.32/t. Evolve Mining’s alternative plant design decimated the capex required at the Tonkolili operation and the quickly completed incremental construction approach ensured that make-or-break export commitments and shipping deadlines were met. The South African companies they serve like their modus operandi. “They do a good job . . . beyond that, I don’t want to comment on contractual terms and details,” Jupiter CEO Priyank Thapliyal said in response to Mining Weekly. “They do a very good job,” was the comment of UMK commercial manager Danie Lourens. According to Sebilo Resources COO John R Rutiri, AMC has in the past few years established itself in the Northern Cape manganese fields as a cost-efficient dry crushing and screening operator: “We consistently achieve 80% manganese lumpy product yield without fail. What puts us, as the client, at ease, is their ability to proactively asses plant performance from both an operational and a reliability point of view and ensure that the client expectations are met by achieving set targets.” Sebilo operates at a cost-per-tonne sliding scale: “This mechanism has proven itself to be mutually beneficial to both the client and the contractor as it entrenches a sense of accountability for all parties involved,” added Rutiri. Reducing Cost Per Tonne Garden cites a long list of ways through which cost per tonne can be lowered, one being the introduction of mobile in-pit crushers and conveyor systems and using surface mining technology, which render the ore more manageable and offer many more handling and processing options. However, if the material is harder than 80 MPa, surface miners become uneconomical, Garden explains to Mining Weekly. Mobile in-pit crushers are typically a third of the cost of primary dumping stations and intermediate stockpiles – the other third can be spent on an in-pit conveying system and the rest is saved. The companies have placed an in-pit crushing machine at the disposal of those wanting to switch to this method of mining and prospective users can also be shown operations around the world that use in-pit crushing, conveying and surface mining to mine millions of tonnes of material a year. An additional benefit of in-pit crushing is far fewer haul trucks being needed to provide in-pit flexibility between crusher and conveyor. Depending on the size of plant, Garden says, it may even be possible to get away with using diesel-cutting, on-highway trucks as the material is –250 mm. Because a conveyor belt can run at a much steeper angle than a haul truck, the stripping ratio of waste to ore becomes less, which, in turn, reduces the cost per tonne. Garden points out that operating and maintaining an overland conveyor is typically a tenth to a fifteenth of the yearly cost of operating and maintaining a haul truck fleet, which is another contributor to cost-per-tonne reduction. Further, conveyor cost is significantly less than the off-highway fleet cost and carbon emissions are dramatically lowered. The reduced in-pit activity conveying provides safety, as well as flexible material storage options. Also, overburden needing to be stripped to get to the ore can be primary-crushed and conveyed and put onto stockpiles using stackers. An unintended consequence of in-pit crushing and conveying is also the need for fewer employees, along with the benefits of lower accommodation, transport, sustenance and maintenance costs. Surface Miners and Coal Garden identifies coal mining as a great application for surface miners, used widely in India to mine more than 85-million tonnes of coal a year. He cites the downstream benefits of using surface miners as having significant fundamental advantages in the design of the process plant to lower the capex and operating expenditure, owing to the best surface miners being able to mine to an accuracy of 10 mm. There is also the opportunity to measure and manage the calorific value of coal as it is being mined. There is no need to blast the coal and crushing occurs simultaneously, which offers many more transport options. “In its simplest form, Evolve Mining designs the sustainable lowest cost-per-tonne mining method, crushing and screening circuit, as well as the process plant, while AMC guarantees the cost per tonne of building and running the operation,” Garden concludes.
Note: Search is limited to the most recent 250 articles. To access earlier articles, click Advanced Search and set an earlier date range.
To search for a term containing the '&' symbol, click Advanced Search and use the 'search headings' and/or 'in first paragraph' options.