Modern Mining July 2016

MINING News

Bushveld announces results of metallurgical test work

minerals processing experts specialising in gravity recovery. The results show that at a top size of 1mm, >70 % Sn recoveries are achieved for enhanced gravity concentration, less than 15 % Sn is lost to tailings during spiralling, and shaking tables achieve at least 85 % recovery, giving over 50 % cumulative recoveries and a final concentrate grade of 74,59 % SnO 2 (58,75 % Sn). Consequently, a flowsheet has been

AIM-listed Bushveld Minerals has announced results from pilot-scale met- allurgical test work and plant design at its Groenfontein tin deposit in Limpopo Province, South Africa.  The test work was intended to assess tin recovery on a plant-scale, gain insight into potential concentrate grades, and to fine-tune plant flowsheet design param- eters. The test work indicates a recovery using gravity concentration of over 70 % for grind sizes of -1 mm. Bushveld released a scoping study on the Groenfontein and Zaaiplaats deposits in September 2014, which envisaged a mining rate of 691 000 t/a at a head grade of 0,12 to 0,23 % SnO 2 to produce 610 to 1 130 tons of refined tin metal per annum post smelting. Following on from the 2014 scoping study, the company decided to revise the development plan for the project to focus on mining the higher-grade zone of the Groenfontein and Zaaiplaats deposits and processing it using a relatively simple gravity separation flowsheet to produce a saleable concentrate product. The scope revision was driven by the company’s interest in executing a low capex, near-term production operation. The aim is to take advantage of a rela- tively buoyant tin market and establish Groenfontein as a standalone tin asset. In order to assess tin recovery param- eters on a plant scale, gain insight into potential concentrate grades, and to fine- tune plant flowsheet design parameters, a large (500 kg) sample of surface ore from historical workings at the Groenfontein deposit was submitted for additional met- allurgical test work at Peacocke & Simpson,

recoveries. With recently updated plant capex and opex estimates at hand, we look forward to finalising infrastructure and mine cost estimates while continu- ing to focus attention on accelerating smaller-scale mine development and commissioning. The tin market has been particularly positive in a generally nega- tive commodity environment with the tin price up 18 % since the start of the year on supply constraints.” 

developed for gravity sep- aration, with crushing and screening and rod-milling to -1 mm. Material is con- centrated via spirals and shaking tables to maxi- mise recovery and SnO 2 concentrate grade. The plant design envisages a 164 160 t/a operation producing up to 510 t/a of SnO 2 . Bushve l d s ays t he next step is to complete flowsheet design and mine-planning studies to determine mine capex and opex parameters, which will be incorporated in a revised financial model. Fo r t une Mo j ape l o, CEO of Bushveld Minerals, said: “ The encourag- ing metallurgical results achieved suppor t our view that high- grade cassiterite concentrates can be produced from the Groenfontein deposit wi t h re l a t i ve l y good

A drill rig working at the Mokopane tin project in Limpopo Province (photo: Bushveld Minerals).

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