Name and Location
Esaase gold project, Ghana.

Client
Asanko Gold.

Project Description
A prefeasibility study completed on the project envisages a contract mining operation using truck-and-shovel surface mining. The basic mining fleet will comprise four 18 m3 excavators and twenty-eight 100 t rigid dump trucks. The trucks will be loaded using hydraulic shovels in a backhoe configuration for the dispatch of ore and waste to the relevant dumping stations.

The haul road maintenance will be sup-ported by two large graders, one smaller grader and two water carts.

The fleet will be supported by dozers, service trucks, tractors, workshop infrastructure and tyre handlers.

The run-of-mine (RoM) ore will be tipped into the RoM pad stockpiles, but there is also an option for direct tipping into the primary crusher. The RoM pad is situated 1.3 km from the pit exit.

Waste will be hauled to three strategic waste dump positions situated in close proximity to the pit to reduce operating costs.
Bench heights employed are based on geotechnical recommendations and practical fleet considerations for the project. Oxide material will be mined using 10 m benches, while fresh material will have 20 m bench heights.

Pit dewatering has been provided for each pit and is integrated into the overall storm- water management philosophy developed for the project.

The proposed processing method entails conventional crushing, milling and gravity recovery, followed by flotation, with the flotation concentrate being reground and then leached in a standard carbon-in-leach (CIL) circuit using Anglo American Research Laboratories (AARL) elution technology. The flotation tails are low enough in grade to be discarded.

RoM ore will be treated in an open-circuit primary crushing system consisting of a RoM bin and gyratory crusher. Product from the primary crusher will be conveyed to a secondary cone crusher.

Secondary crusher product will be routed to a 10 000 t mill feed stockpile. Material will be withdrawn from the stockpile using belt feeders that feed directly onto the mill feed conveyor.

The ball-milling circuit is designed to a feed rate of 635 t/h dry solids. The mill will operate in closed circuit with a cluster of hydrocyclones.

The ball mill will be a 13 MW dual-motor configuration producing a P80 grind. The cyclone overflow will be gravity-fed to a flotation circuit.

The cyclone underflow will be sent to a primary gravity concentration circuit, with the tails being recycled to the mill feed.

The primary gravity concentrator circuit will include two independent concentrators, each with the capacity to treat 400 t/h each. The gravity concentrate will be conveyed to a high-intensity batch dissolution reactor. The pregnant solution from the intensive dissolution reactor will be pumped to the electrowinning cell feed tank.

The flotation circuit will comprise a single bank of seven 130 m3 forced-air rougher flotation cells in series.

The flotation tailings will be pumped to a flotation tailings storage facility, while the flotation concentrate will be fed to desliming cyclones on a regrind circuit.

The cyclone overflow will be routed to a preleach thickener, while cyclone underflow will be treated in a Vertimill. Regrind mill product will be pumped to a secondary gravity concentrator unit.

The concentrate will be routed along with concentrate from the primary gravity concentrator to the intensive dissolution reactor. Preleach thickener underflow will be pumped to the CIL circuit.

The CIL circuit will consist of seven 330 m3 tanks in series. Slurry will flow from one CIL tank to another through intertank pumping screens and launders. CIL tailings will be screened for carbon and pumped to the cyanide and arsenic detoxification circuits.

Detoxification will be achieved by the sulphur dioxide/air process in two detox tanks. Copper sulphate will be added to catalyse the reaction.

Chloride will be added to a third tank, which will be used to facilitate the precipitation of the arsenic present in the tailings stream.
The CIL carbon will be batch-treated in a split AARL elution circuit consisting of an acid wash vessel and a 5 t elution column with a heater facility.

Eluate produced during the elution cycle will be pumped to electrowinning circuit feed tanks.

Eluted carbon will be removed from the column and transferred to the carbon regeneration kiln, after which it will be transferred to the CIL circuit.

Pregnant solution from the CIL elution circuit and the intensive leach reactor will be circulated through an electrowinning circuit.

Loaded cathodes will be removed periodically from the cells and the gold sludge will then be washed, dried and smelted.

The gold produced will be in the form of doré bars, which will be cleaned, labelled, assayed and prepared for shipping to Rand Refineries.

Value
The PFS estimates the initial capital cost of the mine, process plant and associated infrastructure at $286.4-million.

Duration
The mine plan envisioned in the PFS demonstrates that the project can be ready for commissioning within 18 months from the start of detailed engineering work, with first gold produced in the first half of 2015 and steady-state production reached in the second half of that year.

Latest Developments
A definitive feasibility study is under way, with several key opportunities to further improve the project being pursued.

Meanwhile, Asanko has entered into a definitive senior facilities agreement with a special-purpose vehicle of RK Mine Finance Trust I to provide a secured project debt facility for $150-million.

The project debt facility will be used for the development, construction and working capital requirements of the Esaase gold project.

The agreement provides for two term-loan facilities – a $130-million term loan facility and a $20-million cost overrun facility. The overrun facility is provided as an available option to the company, should it be required.

Performance under the agreement is fully secured by the assets of the company’s current subsidiaries and guaranteed by the company until the project’s completion.

In addition to the agreement, Asanko and Red Kite have also entered into an offtake agreement, under which the company has agreed to sell the gold from Esaase for the life of the mine to Red Kite at spot prices during a nine-day quotational period following shipment.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Asanko Gold investor relations manager Alex Buck, tel +44 7932 740 452 or email alex.buck@asanko.com.