E XECUTIVE S UMMARY
The ReCYN™ process (‘ReCYN’) by Green Gold Technologies Pte Ltd (‘Greengold’ / GGT) is a world- leading approach in cyanide recovery, metal recovery and tailings detoxification. Based on an innovative resin-bead absorbent, ReCYN™ reduces cyanide consumption by 50%, capturing free cyanide from the plant tailings and recycling it back into the leach circuit while recovering metal complexes and making them available for sale. In the process, ReCYN™ detoxifies the tailings stream and guarantees 100%-compliant clean water discharge. ReCYN™ is efficient, economical and environmentally friendly. It is the only cost-saving innovation of its kind that is generating results today on an industrial scale. Whittle Consulting Pty Ltd (WCPL) worked with PT Agincourt Resources (PTAR) to assess the value benefits of incorporating the ReCYN™ process into the existing processing plant at the Martabe gold / silver operation in Sumatra, Indonesia. This was the final stage of a wide-ranging Enterprise Optimisation (EO) suite of work with PTAR on the Martabe operation, based on the 2016 reserves. Subsequent to this EO work, further drilling and exploration work has led to a substantial uplift in both reserves ounces and mine life at Martabe. A fully optimised comparable case using the current Martabe processing setup (without the ReCYN™ process) was developed. This utilised strategic pit shell designs developed using Dassault Systèmes’ GEOVIA Whittle™ pit optimisation software (GEOVIA Whittle™) and optimised in Whittle Consulting’s Prober® software (completed as ‘Base Case Optimised Plan’ ). This is already a highly optimised Base Case, calibrated using Whittle Consulting’s EO philosophy and techniques. This includes Activity-Based Costing (ABC) and utilises Theory of Constraints (TOC), on Pits and Phase optimisation in GEOVIA Whittle™. Whittle Consulting’s proprietary software, Prober®, was then employed to calibrate schedule, cut-off, stockpile and blending to maximise net value through the constraint of the operation – in this case, Mill hours (as a proxy for power usage). This approach allows valuation on true constraints, rather than processed tonnes. This means ore feed tonnage realistically flexes, depending on the grind size used and the hardness of the ore feed. The notional value implications of incorporating the ReCYN™ process into these base case designs and schedule was then calculated. This was demonstrated using a four-stage static analysis on the schedule outcomes (i.e. no change to mining schedule, cutoff or destination), revaluing progressively on:
• • •
Recovering Cyanide and re-using in CIL;
Reducing Detoxification costs;
Intensifying Cyanide usage to increase Silver recovery; and
• The ReCYN™ ability to creating a new copper cathode product via electrowinning
To demonstrate the benefit of conducting a full Whittle Consulting Enterprise Optimisation for a material change such as adding ReCYN™, an end-to-end full re-optimisation using the ReCYN™ outcome was conducted. New strategic pit shell designs were developed for all four main sites at Martabe and were then optimised in WCPL’s Prober® optimiser as ‘ReCYN™ Optimised Plan.’ Included in the ReCYN™ NPV calculations for both the initial ‘Static Analysis’ step and the ‘ReCYN™ Optimised Plan’ is a US$5M 2018 capex charge for the installation of the ReCYN™ treatment plant and all opex as appropriate for each step. This does not include a royalty to Greengold that may be applicable at other projects. All results were optimised with Gold at US$1,300 / ounce, Silver at US$19 / ounce and
ReCYN™ Case Study – Martabe Operations
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