The Lake Roe Project is located 100km east of Kalgoorlie between two large gold deposits, the 3.5Moz Carosue Dam mine and the 0.9Moz Karonie gold deposit, located 60km north and 40km south of Lake Roe respectively. The Lake Roe Project comprises six granted exploration licences, plus a mining lease and an exploration tenement application, with an overall area of ~600sqkm.
Breaker identified a significant new 6km-long gold system at Lake Roe in August 2015 using wide-spaced aircore drilling in an area of thin (5m-10m) transported cover. Three subsequent phases of RC drilling commencing in March 2016 resulted in three separate gold discoveries that now constitute one continuous 3.2km-long discovery (Bombora).
The Company has completed ~220,000m of drilling at Lake Roe. Resource drilling commenced in February 2017 and has generally been conducted with four drill rigs (two RC and two diamond). Phase 1 of the Resource drilling was completed in April 2019 and planning is well progressed for the commencement of Phase 2.
A maiden JORC 2012 Mineral Resource for the Bombora discovery was released in mid-April 2018, updated in September 2018 and again in September 2019. The Resource, which is constrained by drilling, open in all directions and only includes drilling within 250m of surface, currently comprises 23.2Mt for 981,000oz at 1.3g/t gold, including a high-grade component of 670,000oz at 2.2g/t gold.
Nearly 80% of the Resource is classified as Indicated and the detailed drilling undertaken to achieve this has also provided an excellent understanding of the deposit geology.
Gold mineralisation at Lake Roe typically occurs as sulphide-impregnated “lode” and stockwork mineralisation in the upper, iron-rich part of a thick fractionated dolerite, the Bombora Dolerite. This style of mineralisation is the dominant mineralisation style in Western Australia and is similar to that at several major gold deposits in WA including the Golden Mile, St Ives, Paddington and White Foil. These deposits typically have good depth potential. Cross sections of drilling results to date show consistent structural framework.
The sulphide lodes represent sulphide-impregnated fault zones (fluid pathways) with up to 10% pyrrhotite and pyrite accompanied by silica, albite, biotite and carbonate alteration and (tensional) quartz-pyrite veinlets that can form stockwork-style mineralisation. The intersection of the mineralised faults and the iron-rich part of the dolerite defines the orientation of the plunging lode and stockwork mineralisation.
Metallurgical testwork results point towards low processing opex/capex with:
- modest ore hardness (ball mill work index <16kWh/t for fresh mineralisation);
- gold recoveries of 96-99% (oxide and fresh);
- gravity gold 31-77% (oxide) and 32-90% (fresh);
- rapid gold leach kinetics;
- low reagent consumption; and
- no deleterious elements.
Environmental, geotechnical and hydrological studies undertaken to date do not highlight any impediments to development.
1 All drill results within the Lake Roe Animation have been previously released. Full details relating to the Bombora Gold Resource are available in the Company’s ASX announcement of 6 September 2018.