The Northern Goldfields of Western Australia is rapidly becoming known for its potential to host numerous long-life, low cost primary production centres of premium SOP, an essential macro fertiliser for high value food crops. In the region, other SOP exploration companies are working towards developing projects with proposed production rates of between 75,000 tonnes per annum (tpa) and 400,000tpa SOP for a minimum of 20 years from trenches and bores.
Trigg Mining’s SOP projects are located near established infrastructure, with all prospects within 100-300km of the Leonora rail head from which the products can be exported through the multi-use ports of Esperance or Fremantle to key international markets, or transported by rail to domestic markets on the East Coast.
In the Northern Goldfields SOP is found in potassium-bearing hypersaline aquifers of the extensive sub-surface palaeodrainage systems where the minerals are thought to have concentrated through the dissolution of basement rocks and the net environmental evaporation of approximately 3 metres per year.
Production of SOP from this primary source occurs through the harvest of brine from trenches and bores targeting the mineralised hypersaline solution. The brine is transferred to on-site evaporation ponds where Australia’s abundant solar energy is harvested to evaporate the water and produce mineralised crystal salts. An on-site ion exchange treatment plant processes the salts to produce SOP and other potentially marketable mineral salts before packaging and transporting for export.
LAVERTON LINKS PROJECT
Laverton Links Project encompasses an expanding footprint east of Laverton where the company is earning in to over 2,347km² across three prospects (Lake Rason, Lake Hope Campbell and East Laverton). The tenements contain more than 265km of brine hosted palaeochannels with the presence of SOP already identified at two of the three prospects.
The Laverton Links Project is the closest Western Australian SOP project to established infrastructure. The western edge of the Project lies from just 35km east of Laverton and is accessible from Laverton via the Lake Rason Road, the Mt Shenton Road, the Great Central Road to Alice Springs (and Queensland) and the Tropicana Gold Mine Access Road from Kalgoorlie. Access to the Leonora railhead is 150km of mostly sealed road and the Eastern Goldfields Pipeline passes directly through the Lake Hope Campbell Prospect.
It is envisaged that the three prospects will combine to become one large SOP production hub with brine sourced out of trenches and bores from several production locations with evaporation ponds established on the playa surfaces. This approach will maximise synergies and minimise capital costs and environmental impact.
LAKE RASON PROSPECT
The Lake Rason Prospect covers 416km², comprising 262km² of salt-lake playa and 40km of subterranean palaeochannel aquifer. The Prospect is located approximately 200km east of Laverton and 60km north of the Tropicana Gold Mine.
Ground gravity, passive seismic, shallow pit sampling and aircore drilling were carried out during Q4 2017. This work has provided sufficient information for the establishment of an Exploration Target¹ for the Lake Rason Prospect of 2.6-9.3 million tonnes (“Mt”) of drainable sulphate of potash (“SOP”). .
¹ An Exploration Target is conceptual and there has been insufficient exploration to estimate a Mineral Resource. It is uncertain if further exploration will result in the estimation of a Mineral Resource.
LAKE HOPE CAMPBELL PROSPECT
The Lake Hope Campbell Prospect covers 814km² and is located approximately 150km east of Laverton and 50km to the west of Lake Rason, along the Lake Rason palaeovalley system. The two tenement contain approximately 95km along strike of the palaeochannel (more than twice the extent of the Lake Rason Prospect).
During the Q4 2017, a reconnaissance trip was carried out to determine access routes and collect shallow pit samples from across the tenements. The 23 samples were collected the day following a significant rain event with visible surface water that may have diluted the samples in some areas. Nonetheless results of up to 6.7kg/m³ K2SO4 were received. These results are comparable to the shallow pit sampling at the Lake Rason Prospect and indicate the potential for mineralisation along the entire palaeochannel.
EAST LAVERTON PROSPECT
Following the success of the shallow pit sampling at Lake Hope Campbell, four tenements covering 1,118km² and comprising the East Laverton Prospect were applied for. This Prospect lies just 35km east of Laverton and encompasses over 130km along strike of palaeochannel and scattered playa areas. This Prospect has no current Native Title determination and the tenements are anticipated to be granted during 2018.
The Lake Throssell Project covers 323km² of predominantly salt lake playa sediments and underlying palaeochannels. The Project is located 200km east of Laverton on the Great Central Road connecting Laverton to Alice Springs and lies within the Ngaanyatjarra Native Title determined lands. Lake Throssell is rated by Geoscience Australia¹ as one of the most prospective lakes for sulphate of potash brine in the region and native title negotiations are progressing in preparation of the grant of the tenement.
LAKE THROSSELL PROJECT
¹Australian Geoscience, A Review of Australian Salt Lakes and Assessment of their Potential for Strategic Resources, 2013