Australian Mining Prospect Award Winners: Explorer of the Year – Sheffield Resources

Emerging minerals sands company Sheffield Resources took home this year’s Australian Mining Explorer of the Year award for its Dampier heavy minerals sands project in Western Australia.

The large zircon-rich Dampier project is located near Derby in the Canning Basin.

Sheffield said it regards Dampier as its flagship project due to its large scale, high grade, high in situ zircon content and potential to produce premium products.

In just 14 months from being granted the Dampier project tenement in September 2011, Sheffield planned and executed a maiden drilling campaign, and completed subsequent testwork and resource estimation.

The company managed to define its large, high grade Thunderbird deposit and a second, underexplored HMS occurrence named Argo. 

The judges said the explorers made hard work look like good luck.

Sheffield-2.jpgIn response Sheffield managing director Bruce McQuitty said the company’s achievements to date have been the result of a strong team.

“We’ve been very fortunate, there’s a lot of skill involved in finding these deposits and we’ve got a small and very skilled workforce,” he said.

“It’s great to win this award.”

McQuitty said Thunderbird is one of the largest and highest grade mineral sands deposits to be discovered in the last decade, with a maiden mineral resource of 1.37Bt @ 6.1% HM (Indicated & Inferred) for 83Mt of contained HM (at 2% HM cut-off).

“It’s very rich in zircon and ilmenite so we expect that it will have a major place within the minerals sand industry globally and within the Western Australian economy, should it make its way through to mining development,” he said.

This resource includes 5.7Mt of zircon, 1.3Mt of rutile, 3.6Mt of leucoxene and 24Mt of ilmenite. 

The zircon product is suitable for the ceramic sector, while its primary ilmenite is suitable for sulphate TiO2 pigment manufacture, and sulphate or chloride slag; and its secondary ilmenite, rutile and High TiO2 leucoxene is determined suitable for the welding electrode sector.

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The processing of mineral sands is somewhat different to other minerals, in that each deposit lends itself to a unique permutation of conventional processing techniques. 

The metallurgical testwork undertaken on the Thunderbird bulk sample in order to determine a minerals separation and processing route suited to the Thunderbird products also required innovation. 

Mineral products were ultimately obtained via customisation of a sequence of conventional mineral separation plant processing techniques, including attritioning, magnetic, electrostatic and gravity separation techniques.

The Thunderbird bulk sample was deslimed using conventional cyclones and processed through a 6 stage spiral (gravity) circuit.

Heavy mineral concentrate was then upgraded to +90%HM concentrates via a two-stage wet, high-intensity magnetic separation, attritioning and gravity concentrate upgrade stages to produce magnetic and non-magnetic ilmenite and zircon/high TiO2 concentrates, respectively.

McQuitty explained the Thunderbird Scoping Study is progressing on schedule and is due to be completed later this year.

“We are currently at the scoping stage on our major project, the Thunderbird Deposit, and we want to take that through to feasibility and eventually to mine but we have other projects as well that we’re chasing up so we have a very fertile project pipeline,” he said.

The deposit has favourable geometry, occurring as a thick, shallowly-dipping sheet 4km x 5km in area, extending from surface and open in most directions.

Due to the shallow dip of the deposit, approximately 40 per cent of the total resource area has less than three metres of overburden.

Sheffield has recently completed its second drilling program on the project and is looking to upgrade the resource estimate.

“We’re looking to upgrade the resource on the project as a result of that drilling and we’re moving into prefeasibility next year,” McQuitty said.

“We’re looking to take that further towards mine development perhaps in 2017 or around that timeframe.”

The results of the second drilling results, released in November continue to confirm continuity of high grade mineralisation at Thunderbird.

The 2013 drilling programme at Dampier comprised 326 holes for a total of 21,747m across the company’s Thunderbird and Argo prospects.

Sheffield Resources also took out the Best Emerging Company Award at the Diggers and Dealers forum in August.

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