Metallurgical Testwork Programme Confirms Viability of a Conventional Processing Flowsheet for Tin Project
Successful Metallurgical Testwork Programme Confirms Viability of a Conventional Processing Flowsheet for Elementos’s Oropesa Tin Project
Wardell Armstrong is pleased to announce the completion of a programme of metallurgical testwork and flowsheet development in support of a definitive feasibility study (DFS) for Elementos’s Oropesa Tin Project. Oropesa, based in Andalucia, Spain, is amongst the largest undeveloped, mineable tin projects in the world, with a recent JORC compliant Measured, Indicated and Inferred Resource of 75,400 tonnes of tin.
By integrating a large-scale pilot plant campaign, in which over two tonnes of material was subjected to a process of grinding, sulphide flotation, and multiple stages of gravity separation, with a series of bench-scale magnetic separation and tin flotation tests, Wardell Armstrong was able to demonstrate production of a high-grade, low-impurity tin concentrate (see flowsheet below).
Wardell Armstrong always aims to deliver maximum value for its clients, with a focus on process efficiency, project economics and environmental considerations. The flexibility afforded by the modular design of the Wardell Armstrong pilot plant allowed multiple stages of processing to be integrated into a single stage of testing, providing considerable time savings, and giving a stronger indication of potential plant performance (see video below).
The results of the metallurgical testwork, presented in the Table below, demonstrated that a conventional, industry-proven flowsheet was suitable for producing a high-grade tin concentrate from a bulk sample considered representative of the expected average mill feed grade. The combination of grinding, flotation, gravity, and magnetic separation yielded a tin concentrate assaying 61.4% Sn at 74.1% recovery, with low associated levels of iron (4.90% Fe) and sulphur (3.18% S(TOT)).
A subsequent programme of variability testing, undertaken on 32 samples representing spatial, domain, and grade variation, provided additional confidence. By applying the optimised flowsheet and conditions to each of the 32 samples, Wardell Armstrong has been able to demonstrate the robustness and versatility of the developed flowsheet to cope with potential variations across the deposit. This included a series of comminution tests undertaken to investigate the effect of fluctuations in rock hardness, further de-risking the process design.
Elementos Managing Director, Joe David, said the company was pleased with the robust metallurgical upgrades achieved:
“After a prolonged yet detailed metallurgical program Elementos is very pleased to be able to release these robust metallurgical results. These results confirm the DFS flowsheet for the project with a production of a commercially appealing, high grade and low impurity, tin concentrate of around 61% Tin. The resulting concentrate is not only low in impurities but is confirmed to be produced with economic average recoveries above 74%, using a conventional and modern tin concentrate process flow sheet.
“This pilot scale flowsheet is now the basis for the DFS. We are pleased that this test work has built-on the core flowsheets from previous test work programs, with only minor optimisation changes being made during this program to creating a more robust flowsheet and concentrate product.”
