Horseshoe Metals (ASX:HOR) has completed an updated open pit optimisation at its Horseshoe Lights Copper Gold Project in Western Australia, outlining a single pit shell containing 12,337,226 tonnes at 0.77% copper for 95,033 tonnes of contained copper to a maximum depth of 260 metres, using a copper price assumption of A$25,000 per tonne.

Key Points

  • Updated pit optimisation at A$25,000/t copper price outlines 12,337,226 tonnes at 0.77% Cu for 95,033 tonnes of contained copper from a single open pit to 260 metres depth
  • The new result contains 71% more copper in one pit shell compared to the December 2014 pit optimisation, which returned 5.99Mt at 0.93% Cu for 55,700 tonnes contained copper at A$9,925/t
  • Existing Mineral Resource Estimate for Horseshoe Lights is 12.85 million tonnes at 1.00% Cu, 0.1g/t Au and 1.9g/t Ag for 128,600 tonnes Cu, 36,000 oz Au and 793,000 oz Ag
  • The open pit optimisation has captured approximately 74% of the contained copper in the 2014 Horseshoe Lights MRE at a notional strip ratio of 5.0:1
  • The company stated it expects to report XRF and check assay DSO sampling grades in the near term as it pursues multiple near-term sales channels for DSO material

Updated Open Pit Optimisation Parameters and Results

The revised pit optimisation used a copper price of A$25,000 per tonne, with costs based on current market rates for mining, processing and operating. Input parameters included a mining dilution of 15%, mining recovery of 90%, a payable copper price of 80%, processing costs of A$30.00 per tonne for oxide, A$50.00 per tonne for transitional and sulphide, and an annual discount rate of 8%. No value was attributed to contained gold and silver in oxide and transitional material. The optimisation applied a cut-off grade of 0.1% Cu and a 300-metre buffer zone to assess the effect on existing stockpiles, waste dumps and surface infrastructure.

Comparison With December 2014 Scoping Study

The December 2014 Pit Optimisation and Scoping Study used copper price assumptions of A$7,750/t, A$8,825/t and A$9,925/t. At the highest price of A$9,925/t, that study identified potential to mine 5,990,000 tonnes at 0.93% Cu for 55,700 tonnes of contained copper, resulting in 47,375 tonnes of recovered copper, 12,730 ounces of gold and 271,100 ounces of silver over a six-year production schedule. The current 2026 optimisation at A$25,000/t has resulted in 71% more copper contained in a single pit shell encompassing both the Main Zone and Motters mineralisation.

Exploration Target and Mineralisation Continuity

Current Exploration Target modelling confirms continuity and predictability of Main Zone mineralisation from 200 to 600 metres below surface, and Motters Zone from 80 to 300 metres below surface. The Exploration Target consists predominantly of sulphide mineralisation with minor oxide and transitional material within a west-dipping and north-plunging zone with a surface strike of approximately 700 metres. Oxide to transitional mineralisation at Main Zone and Motters Zone is interpreted to extend from surface to between 60 and 80 metres below surface. The company stated the Exploration Target supports its aims to expand the existing Mineral Resource Estimate footprint at the Horseshoe Lights Project.