Advanced gold and copper explorer Alice Queen (ASX: AQX) has commenced a scoping study at its Horn Island gold project in Queensland’s Torres Strait to explore the economics of a potential open pit operation at the historic mine.
The study will include data from a recently-completed phase one infill drilling campaign designed to further investigate the controls, intensity and distribution of gold mineralisation at the project.
Comprising 35 holes for a total 7,072m immediately west of the existing Horn Island pit, the campaign’s first 15 holes all returned gold assays grading greater than 0.5 grams per tonne.
Best results were 2m at 22.9g/t gold from 37m including 1m at 43g/t from 37m; 19m at 3.2g/t from 80m including 3m at 10.9g/t from 93m; and 5m at 4.2g/t from surface including 1m at 17.3g/t from surface.
The scoping study will also feature results from updated metallurgical testwork as well as a pilot-scale ore sorting testwork program conducted last month to assess the amenability of Horn Island’s mineralisation to ore sorting techniques.
That program focused on a 2,000kg sample of fresh drill core and 5,000kg sample of low-grade stockpile material, both currently being assayed by ALS in Perth with results expected by April.
The study team will also investigate improving the mined head grade through improved definition of the mineral resource and possible application of pre-concentration by Dense Media Separation (DMS) and ore sorting techniques.
Updating the mineral resource
An existing open pit inferred resource of 7.9 million tonnes at 1.9g/t gold for 492,000 ounces gold will be updated as part of the study process and will form the basis of development work moving forward.
The existing inferred resource forms part of the “excluded zones” which remain separate from the Horn Island gold project joint venture with St Barbara (ASX: SBM).
Other excluded zones are the historic mine infrastructure which includes certain road areas and decant water dam, historic waste dumps, low-grade ore stockpiles, run-of-mine pad, and all alluvial gold across Horn Island to a depth of 5m below surface.
Alice Queen said the updated mineral resource model would be used to create a pit optimisation and processing plant flowsheet design.
The company will progress a phase two infill reverse circulation drilling program in an effort to further improve confidence in the resource model and it is expected these results will be included in the study.