Following the halting of operations at the Homase gold project, in south-western Ghana, in 2023, to review the design of the processing plant, Aim-listed gold producer GoldStone Resources has reported successful continued production since the second half of 2023 through to the first half of this year.

In an operational review published on July 8, the company said current operations were achieving mining and stacking of agglomerated ore at an average of 5 400 t a month.

Production for the year to date amounted to 1 350 oz of gold following the last gold pour on June 18.

"The difficult decision was taken in 2023 to halt production and review the design of the processing plant. Despite the many challenges associated with the company's ordinary shares being suspended from trading for such a long period of time . . . the upgraded plant is delivering the improved heap-leaching gold recoveries we targeted,” GoldStone CEO Emma Priestley said.

The company also reported a significant increase in gold recovery to 68% over the past six months, stating that it is on track to increase production to deliver the planned 50 000 t of stacked and agglomerated ore, targeting gold production of 1 000 oz a month within six months.

Meanwhile, exploration activities are reported to demonstrate the potential to materially expand Homase's current resource of 602 000 oz of gold at an average grade of 1.77 g/t

"Importantly, the capital expenditure requirements to increase gold production are relatively minimal henceforth, merely requiring completion of Leach Pads 5, 6 and 7 and construction of an additional pond. These works will allow the company to further realise the considerable potential of the Homase mine's oxide resource base, with the key objective of increasing monthly gold production to 1 000 oz within six months and achieving [increased operating] cash flow through optimising unit costs and decreasing general and administrative exposure,” Priestly said.

 In 2023, GoldStone elected to suspend mining to evaluate processing options. This was facilitated by the £2.4-million investment, which enabled engineering improvements and further testwork to be undertaken.

GoldStone’s process plant on site was extensively upgraded during 2023, with the acquisition of vibrating screens, improved cement feed, and the introduction of a radial stacker, resulting in a significant increase in gold recovery rate to 68% demonstrated over the past two months, compared with a 2022 average of 34%.

The company said that it is now on track to start increasing production to deliver the planned 50 000 t of stacked and agglomerated ore within six months, and this level is expected to be maintained on a monthly basis to ensure that gold-production targets of 1 000 oz a month can be achieved.

GoldStone has now hired a 50 t excavator and three 45 t articulated dump trucks, which will enable a substantial increase in production from Homase's Pit 2, which is yielding an average grade of 1.1 g/t.

On the heap leach pads, the company has levelled and compacted Pads 1, 2 and 3 in readiness for the second lift-superimposition of the next layer of ore for leaching. Pad 4 is nearing completion, Pad 5 is being built and civil engineering has begun for Pads 6 and 7, GoldStone said.  

In 2023, the company also commissioned the onsite laboratory, thereby allowing the company to undertake continuous column leach testwork and fire assays, with the appropriate microbalances and an atomic absorption machine to ensure accurate analysis. This facility now enables better grade control, critical for both mining and processing, GoldStone said.  

Although it faced limited cash resources during 2023 and the first half of 2024, the company said that it is still focused on resuming mining and increasing production. With the equity raise announced on May 24, the company was able to return to trading and progressing operations. 

EXPLORATION
Throughout 2023 and in the first half of this year, GoldStone continued to review historical exploration datasets for the Homase mine and its extended mineralised trend, which extends north-east and south-west of the current Homase mine and is open at depth.

Within the Homase mining lease, the mineralised zone extends about 5 km, including a substantial deeper gold resource of about 600 000 oz underlying and north-northeast of the Homase pit. There is also a parallel zone of about 800 m in length within the exploration permit area that has yet to be systematically explored, the company said.

Historical records show that there was significant close-spaced drilling undertaken beneath the former pit mined by Ashanti Goldfields – now AngloGold Ashanti – between 2002 and 2003, and it is evident that the grade improves markedly at depth with the transition through 5 m to 10 m of transition ore to sulphide ore, GoldStone said. This former Ashanti pit is referred to as Pit 4 under the current mine plan.

Notwithstanding the mineralogical changes with depth, the company believes that the oxide cap that is currently being mined along the Homase trend is about 40 m to 50 m thick and averages at 1.1 g/t gold.

The company is fortunate to have the feasibility study and metallurgical testwork data that was undertaken by Ashanti in the early 2000s and this shows that the primary sulphide ore is predominantly non-refractory,” GoldStone said.

Drilling beneath Pit 4 in 2011 and 2012 was made in sections to 25 m intervals along strike. At the time, the results showed mineralised zones more than 10 m wide on the vertical with grades of more than 6 g/t.

GoldStone said that it intends to undertake further drilling of this section of the Homase trend, including Pits 1 to 4, targeting the primary ore.