Modern Mining

ASX-listed Prospect Resources has announced a further increase in the ore reserve estimate at its flagship Arcadia lithium deposit in Zimbabwe to 26,9 Mt at 1,31 % Li2O.This is a 70 % increase in tonnes compared to the Pre-Feasibility Study (PFS) and secures ore supply for a plus 20-year mine life. According to Prospect, Arcadia ranks as the largest JORC Code reported lithium deposit in Africa.

Commenting on the increase, Prospect’s Chairman, Hugh Warner, described the new estimate as a “great result” for Prospect’s shareholders. “Part of the reason for such a massive increase in our ore reserve is the effectiveness and detail of our exploration programme, the high percentage of diamond core holes relative to RC holes and the benefits of our detailed assay and XRD analysis programme – which, combined, reduces risks associated with our orebody knowledge and helps with future grade control planning,” he said.

Arcadia One of 90 DD holesOne of 90 diamond drill holes at Arcadia (photo: Prospect Rsources).

Touching on recent political developments in Zimbabwe, Warner referred to the “peaceful transition of leadership in Zimbabwe” and said Prospect was well placed to participate in and contribute to the rejuvenation of the country. He added that the company was working to bring the deposit into production in the shortest possible time. “It is worth remembering that we have achieved this result in less than 18 months from our first drill hole,” he stated.

The PFS announced by Prospect in July this year declared an ore reserve estimate of 15,8 Mt grading 1,34 % Li2O. The PFS identified significant volumes of inferred mineral resource within or adjacent to the study’s pit designs. A drilling programme to increase and upgrade the mineral resource estimate resulted in a 31 % increase in the high grade (>1,0 % Li2O) measured and indicated resource estimate, as announced to the ASX in October 2017.

In generating the updated ore reserve, the physical and cost parameters used in the PFS were applied including the appropriate modifying factors.

Pit shells and pit designs were generated using Whittle and Surpac software from which the ore reserve, as delivered to the process plant, was derived. The ore reserve is contained within three open pits comprising the main pit and two satellite pits. The resulting mine plan, completed to PFS level, details a project with a plus 20-year mine life based on an ore processing rate of 1,2 Mt/a. The mine plan is technically achievable, economically viable and robust under a range of pricing, physical and costs parameters scenarios, says Prospect.

The Arcadia project is located approximately 38 km east of Harare close to the long-established Arcturus gold mine. The project occupies an area of more than 14 km2 and consists of some historical lithium and beryl workings within an existing agricultural area partially surrounded by a number of hills rising some 50 m above the central basin floor.

The findings of the PFS defined a 1,2 Mt/a mining and processing operation producing, on average for the life of mine of 15 years, 75 000 t/a spodumene and 155 000 t/a petalite concentrates destined for the battery (chemical) and glass/ceramics (technical) markets. The PFS estimates the capital cost of the project at US$52,5 million.

Mining at Arcadia would be by conventional open-pit methods. The proposed concentrator plant is based on conventional DMS and froth flotation technology and would produce three lithium streams. The processing plant comprises key areas including three-stage crushing, grinding, dense media separation, mica-flotation, spodumene flotation, petalite flotation, magnetic separation, concentrate dewatering and drying, and tailings filtering.

Prospect is also evaluating the development of an integrated lithium chemical plant at Arcadia. In October the company said that it had produced battery grade >99,5 % lithium carbonate in its custom laboratory in Kwekwe, Zimbabwe.

In a major step forward for the project, Prospect announced in November that it had executed a conditional placement and offtake agreement with Sinomine Resources Exploration Co and Sinomine Exploration (Hong Kong) Co. In terms of the agreement, Sinomine will invest A$10 million via a share placement in Prospect. Prospect, for its part, has agreed to sell to Sinomine 390 000 tonnes of spodumene concentrate and 1 097 000 tonnes of petalite concentrate over a proposed seven-year period. The parties also agreed indicative terms for a facility agreement and a build-and-transfer contract.

Commenting at the time on the agreement, Prospect’s Warner said: “The transaction will fully fund the building of Prospect’s lithium mine and plant at the Arcadia lithium project through to full production. This deal is the culmination of close to a year’s work. During this time, we have developed a close relationship with Sinomine and we like their style and commitment to both the project and the Prospect team. This is evidenced by the significant commitment to developing this important resource. Both teams are cooperating closely to integrate their considerable technical knowledge into a structured efficient roll out. As previously reported, the Prospect team has been carefully assembled over the last 18 months in preparation for just such a scenario.”

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