Rustenburg-based miner LANXESS Chrome Mining – owned by German speciality chemicals company LANXESS – is investigating the viability of a tailings retreatment project, in addition to defining the resource of its existing opencast licence and that of its recently acquired land, thereafter combining these with the current efficient underground operations, says LANXESS Chrome Mining CEO Sarel Ferreira.
He explains that the company is exploring options relating to the 3.4-million-tonne tailings dump. “We’re in talks with a couple of companies, looking at the possibility of partnering with them for a mutually beneficial tailings reprocessing project.” He explains that these companies are in the process of compiling their own feasibility studies for the tailings project.
The tailings dump has a grade of about 1.67 g/t platinum-group elements (PGEs), including rhodium, platinum and palladium, says Ferreira.
“I believe that the resource can be upgraded – through concentrating and processing – from about 1.67 g/t PGEs to just over 3 g/t and counting grams per ton PGEs, which we could possibly sell to platinum companies.” He adds that the tailings dump probably has on average, between 21% and 26% chrome content, in addition to its significant PGE content.
Ferreira notes that the tailings project and LANXESS’s definitive resource project will be conducted in parallel. He explains that the exploration drilling under way on LANXESS’s designated openpit area, as well as on its newly acquired land, is meant to produce ore reserve statements. He adds that this project is being conducted in-house.
“We have already completed about 25 holes and the samples are undergoing chemical analysis to verify the composition of the reef, the mineralogy and chrome content.”
Ferreira expects that, in the next couple of years, the company’s openpit mine will be operational.
He notes that LANXESS has an additional four portions of land (A1, A2, A3 and A4) – which were acquired in November 2013 and successfully included into LANXESS’s mining rights in September. This includes a portion east of the current licence area near the Wonderkop smelter.
Ferreira explains that LANXESS is exploring backfill mining scenarios on the Wonderkop portion, explaining that, while backfill is a common practice on gold mines, the relatively shallow depths of PGE mines ensure that it is not a common practice for pillar stability.
However, the backfill methodology will work best with the Wonderkop portion, he says, because of its geographical composition and geological features.
Ferreira explains that the newly acquired ground extends the current life-of-mine (LoM) of the underground operation to about 2030, while the backfill methodology could add three or four years if the mine decides to do pillar retreat mining. The backfill will act as structural support to ensure that the ore-rich pillars can be mined.
Further, the previously mentioned scenarios only consider LG6 and LG6A chrome ore. Ferreira explains that the underground mine is located on the LG6/LG6A seam, but that there is a “middling” seam of MG1 to MG4 ore – on the existing licence area – that has never been mined. When the middling band is taken into account, the LoM extends by an additional 20 to 30 years. “This means that we could comfortably mine up to about 2060.”
Ferreira suggests that LANXESS’s mining operations will primarily take place underground, with a small openpit operation producing a relatively small tonnage for a few years, and some additional chrome coming from the tailings project. He explains that this is a feasible mine plan, given the realities surrounding the geology and costs.
“The really deep openpit mines in South Africa are about 350 m deep and are usually gold, iron-ore and copper, including some other commodities. With openpit PGE mines, depth is a major driver on costs and efficiencies, which effects overall effectiveness of such an operation. Once a PGE mine has reached these uneconomical depths, it is more cost effective to transition to underground mining, because the associated costs – including transport-related costs – increase as the pit deepens,” comments Ferreira.
Ferreira explains that the underground chrome mine is approaching key milestones – two-million fatality-free shifts (later this month), and new highs in terms of output and revenue.
He notes that the mine’s ability to outperform the local chrome mining industry is a result of its ability to run an “optimal and cost-effective” operation, which ensures that it is well positioned to take advantage of any increase in the chrome price or any related commodity prices.
“Although the recent spike of chrome ore on the international market was short-lived, it proved that the mine could provide the right volumes in a safe, cost- effective and sustainable manner.” LANXESS’s operating strategy has ensured that the mine is able to remain profitable, despite lacklustre prices.
Further, LANXESS produces “premium products for premium end-users”, highlights Ferreira.
“We produce premium, higher- grade, lower silica content chrome products, used in the production of chrome chemicals for leather tanning, pigments, and chromic acid as well as foundry sand. Our premium product is Cromtec 50, which is used in the foundry industry.”
Ferreira notes that, as a German company, quality means much more to LANXESS. “It means producing the highest performance products that deliver what is promised. We want our customers to be able to rely on us in all matters and at every stage of our chrome value chain. At our mine, quality means we supply premium chrome ore for local and international markets. From the first conversation to the perfect implementation, meeting and exceeding expectations.”
Through embracing Xact, LANXESS’s occupational safety programme applicable to all business units and group functions worldwide, each employee takes responsibility for health and safety procedures at the mine.
This has resulted in the mine achieving a zero lost-time injury frequency rate and a zero reportable injury frequency rate for the first half of the year. Thereby, the Department of Mineral Resources has identified the mine as a safety leader in the chrome industry in the North West area.
Currently, the mine stands on 217 lost-time injury-free days, a new record for the mine as it continues well on its way to zero harm, says LANXESS.