COM Tertiary XRT sorter
A complex flowsheetThe Renison mine is 50% owned by Metals X through the Bluestone Mines Tasmania Joint Venture (BMTJV). It is the only major tin project in production in Australia with a mining rate of close to 1Mtpa, although the concentrator is restricted at 750,000tpa. The extreme humidity, with an annual rainfall of over 3,000 mm, and the highly acidic processing water with pH around 4.5, creates unique challenges for the sorting process, the equipment, and waste management, which BMTJV resolved with TOMRA’s help.
The underground mine operates a primary crushing system before the material is transported to the surface through a shaft. Once there, it enters the pre-concentration plant, where it undergoes a 3-stage crushing, screening and cleaning. The particles are split into two fractions – 10 to 25mm and 25 to 60mm – which are fed into two TOMRA X-Ray Transmission (XRT) sorters. The output consists of two streams: the product, which is transferred to the wet plant, and the waste, which is fed into a TOMRA EM sorter to separate acid-forming sulphides. In the wet plant, the product goes through primary grinding followed by bulk sulphide flotation. The tailings are processed downstream to concentrate the cassiterite tin mineral through gravity concentration, gravity tails are further treated via desliming and tin flotation. The combined concentrates are fed to a leaching circuit to remove carbonate minerals, after a final wash stage the concentrate is de-watered and dispatched.
BMTJV approached TOMRA to address two key requirements. The first was the need to upgrade their tin feed to the plant: “The Renison Tin operation wanted to achieve economies of scale, putting more tons through the front end of the plant without upgrading the back end downstream – we wanted to do more with less,” explains Ben Wraith, Principal Project Metallurgist at BMTJV. The second requirement was to address the environmental issue of removing acid-forming sulphides from the waste. Following site visits and extensive discussions with BMTJV’s teams, TOMRA proposed a solution that addressed the tin feed quality with two COM Tertiary XRT 1200 sorters and the waste issue with a COM Tertiary EM 1200 sorter. A team from BMTJV visited the TOMRA Test Center in Sydney, where they observed what the XRT sorter operating at capacity is capable of and experienced first-hand the exceptional accuracy of TOMRA’s XRT sensor. “Our XRT stands out for the high spatial and density resolution and its ability to do contrast sorting, identifying fine high-density tin inclusions in the ore with an accuracy that has no equal on the market,” says Gavin Rech, Technical Manager at TOMRA. “On top of that, it can separate it from the acid-forming sulphides, so that we have the ability of pulling the tin into the first product and sending the rest to the EM sorter.”
We've broken multiple production records in the last year in tin units...because the machine performs over and over again if you treat it right and if you prepare your feed correctly.