Tag Archives: AusTin Mining

AusTin’s Granville East mine waste to lay ground for wind farm

AusTin Mining says it has entered into a non-binding heads of agreement with Lucas Total Contract Solutions to supply non-acid forming (NAF) waste rock from the Granville East mine, in Tasmania, Australia, for construction purposes at the Granville Harbour Wind Farm.

The A$280 million wind farm will comprise 31 turbines with a 112‐MW capacity and is expected to be operational in late-2019, according to AusTin.

AusTin commenced tin mining at the Tasmania operation in February.

The wind farm is around 5.5 km from the Granville East mine and, subject to obtaining all regulatory permits, the agreement contemplates the sale of up to 120,000 t of NAF waster from the existing waste rock emplacement area, immediately east of the open-pit mine.

“The proposed sale of NAF waste rock provides two key benefits to AusTin Mining, being an additional revenue stream and reduced provision for future site rehabilitation,” the company said.

“The financial benefits of the agreement will be analysed upon receipt of all regulatory permitting conditions but are expected to equate to four or five months of owner mining operating costs, with a commensurate reduction in the previously announced forecast cash costs.”

AusTin Mining said it had commenced the process to obtain all necessary approvals and would work with Lucas to complete the process as soon as possible, noting “the potential environmental benefits of reduced ground disturbance at both the GranvilleEast mine and the wind farm”.

In the interim, the company said processing of ore production in concentrate continued at the processing plant.

AusTin transitions to owner mining at Granville East mine in Tasmania

AusTin Mining has commenced owner mining at the Granville East tin mine in Australia, just over a week after liquidators were named to its previously appointed mining contractors, Jemrok Pty Ltd.

The decision to adopt owner mining as opposed to appointing another contractor was based on minimising disruption to the project by using existing equipment at site and employment of ex-Jemrok employees, the ASX-listed company said.

The company commenced tin mining at the Tasmania operation just last month.

AusTin Mining said: “The company considers owner mining will deliver greater control and improvement in mine productivity following a decline in productivity in early 2019.

“Under the owner mining model, waste mining operations have resumed following a period of lost production attributable to the collapse of Jemrok, and ore mining is expected to resume in the coming fortnight.”

Owner mining operating costs for Granville are estimated at A$100,000-A$130,000 ($70,655-$91,851) per month depending on blasting requirements and are inclusive of equipment rental, fuel and labour. “Owner mining should deliver a lower mining cost based on the removal of the contractor’s margin,” the company said.

Jemrok was previously contracted to also provide crushing and ore-haulage services but the company is now progressing discussions with a third party for these services. In the interim, AusTin has transported the relatively friable hangingwall ore that doesn’t require crushing to the processing plant for treatment.

This has, initially, led to an increase in plant feed grade but has necessitated a change in operating strategy to accommodate the increased level of sulphides associated with this material in order to achieve the targeted concentrate grade of 60% Sn.

“Upon implementation of contract crushing, the company will be able to increase the proportion of competent skarn ore that contains lower sulphide level and historically has been the predominant ore source for the project,” AusTin said.

AusTin Mining weighing up ore-sorting at Taronga following positive tests

TOMRA is continuing to win praise for its sensor-based ore sorting technology, with AusTin Mining being the latest company to say pilot test work indicated the process could remove a significant amount of waste and boost grades.

The company had previously carried out a 60 kg trial with TOMRA on material from the Taronga project in New South Wales, Australia, which indicated X-ray Transmission (XRT) ore sorting was effective.

The latest test work went a step further, with 1.6 t of material grading 0.15% Sn from the Northern Zone of the Taronga deposit being crushed and run through an XRT-1200 sorter in a series of tests for different sizes.

In summary, the latest result indicated:

  • Significant mass rejection (up to 66%) to waste may be achieved. This could either reduce the scale of the downstream processing plant and/or enable an increased plat throughput;
  • Uplift (up to three times) in the grade of sorted product, which could increase the tin units reporting to a downstream processing plant;
  • Increase (over three times) in the grade of fines (-8 mm) material, highlighting the potential for preliminary beneficiation in conjunction with ore sorting, and;
  • Consistent waste grades across all tests, indicating the potential to increase tin recovery with increasing feed grade.

CEO, Peter Williams said of the results: “Aus Tin Mining is encouraged by the benefits ore sorting could deliver for the Taronga tin project, not only including the potential uplift in grade, but also the scope for lower costs and the long-term potential opportunity to exploit more of the mineral resource.”

Williams added that the Stage 1 project at Taronga would provide an “ideal opportunity to test and optimise the technology”.

In 2015, the company announced it would commence a Stage 1 development comprising a 340,000 t trial mine within the Northern Zone ore reserves and pilot processing plant able to produce a saleable concentrate over an 18-24 month period. The company is currently in the process of progressing outstanding regulatory approvals and contractor negotiations for this project.

In the coming weeks, AusTin intends to evaluate whether to proceed with an ore-sorting trial in conjunction with the Stage 1 project, including considerations for additional costs and existing approvals.

“The company will also transport the residual material from the ore-sorting test work to the Granville tin project to assess the material for downstream gravity and flotation processes,” the company said.

The Taronga tin project comprises two major zones of quartz-cassiterite, sheeted vein-style mineralisation. The Northern Zone accounts for approximately 70% of the total mineral resource (27 Mt at 0.15% Sn for 40,100 t contained tin) and is open at depth. The Southern Zone (9.3 Mt at 0.19% Sn for 17,100 t contained tin) comprises a very coarse cassiterite demonstrating superior metallurgical properties plus contains higher tin, copper and silver grades.