Figure A: Project Location
Thunderbird Mineral Sand Project is in the Kimberley region in northern Western Australia on the Dampier Peninsula and lies 70 km west of Derby and 30 km north of the sealed Great Northern Highway (GNH) joining Derby and Broome.
Thunderbird is the first significant heavy mineral sand deposit to be discovered in the Canning Basin and is one of the largest and highest-grade mineral sands deposits globally, including those currently in production. The deposit, hosted by highly weathered Broome Sandstone contains valuable heavy minerals including ilmenite, zircon, leucoxene, rutile and anatase.
Figure B: Continuous Mining & Rehabilitation Process
The mineralisation is in a thick, broad anticlinal sheet like body striking northwest, folded from flat dip to a dip of about four degrees, extending under cover to the southwest. The areal extent, width, grade, geological continuity and grainsize of the Thunderbird mineralisation are interpreted to indicate an offshore, sub-wave base depositional environment, similar to the interpreted depositional environment of the WIM 150 deposit of the Murray Basin in south- eastern Australia.
Thunderbird has progressed from an exploration project to a substantial development project with significance to the local region and the State of Western Australia (State). Sheffield was campaign resulted in Sheffield declaring a large high-grade maiden Mineral Resource for the Thunderbird deposit on 18 December 2012.
Sheffield completed a Scoping Study in 2014 and Pre-Feasibility Study and PFS Update in 2015, leading to the announcement of a maiden Ore Reserve in January 2016. A Bankable Feasibility Study on Thunderbird was completed in March 2017 demonstrating the Project could produce and market high-quality zircon and ilmenite products at large volumes near to Asian markets.
The 2017 BFS described a typical mineral sand mining operation where a moving void extracts the valuable mineral sands, with waste materials returned to the void enabling progressive rehabilitation of the mined area. Topsoil and overburden are excavated and transported using truck and excavator. Ore is excavated, screened, slurried and then pumped to a nearby wet concentration plant. Retaining cells are constructed in the developed mine void for the return of process tails. Topsoil is returned in a continuous rehabilitation process.
Minimal pre-strip is required to access the orebody as initial mining is concentrated in an area of ore occurring near surface. As the mining void is established, increasing amounts of overburden are mined and directly returned to the mining void as backfill.
Sheffield completed a Bankable Feasibility Study Update in July 2019, announcing the current Ore Reserve for the Stage 1 and 2 of Thunderbird totaling 748 Mt at 11.2% HM comprising 219 Mt at 13.7% HM (Proved) and 529 Mt at 10.1%HM (Probable) with a plan to produce zircon products and ilmenite suitable for manufacturing titanium dioxide pigment or smelting into chloride slag.
In January 2021, Sheffield and Yansteel executed binding agreements for the formation of a 50:50 Joint Venture (Kimberley Mineral Sands Pty Ltd or ‘KMS’) to own and develop the Thunderbird Mineral Sands Project (Thunderbird) and adjacent tenements on the Dampier Peninsula. The parties have agreed that the development concept for Stage 1 of the Project will be a 10.4mt per annum mine and process plant producing a zircon rich non-magnetic concentrate and LTR ilmenite.
The Stage 1 and 2 of the Project has current mine life of greater than 37 years with low environmental impacts and long-term community benefits. The Project has all necessary primary approvals in place and is ready for contracting and subsequent construction.
The Project includes the Night Train deposit, 20km to the east of Thunderbird, with an Inferred Mineral Resource of 130Mt @ 3.3% HM and a further 14 zones of significant mineralisation along a 160km long highly mineralised trend.
The Night Train prospect is located 20km south of Thunderbird. Mineralisation has been defined on one main line of drilling and is open in most directions.
At 1% HM cut-off the mineralisation is 1.6km wide and from 4.5m to 24m thick (average 11m), with an average HM grade of 4.04%. At 3% HM cut-off, mineralisation is 1.0km wide, from 3m to 12m thick (average 7.5m), with an average grade of 6.40% HM.
Night Train has a high value mineral assemblage with 92% VHM, comprising 15% zircon, 53% leucoxene, 8% HiTi leucoxene and 16% ilmenite. The heavy mineral is free from coatings and has a very high zircon content. The mineralisation is hosted by fine, clean, predominantly quartz sand.
Night Train is located just 2km from the proposed Thunderbird Project haul road or 20 km south east of the proposed Thunderbird process plant. This substantial new discovery is further evidence of Sheffield’s prime position in the emerging Canning Basin mineral sands province.