Further Metallurgical Test Work on Gubong Ore Sample Yields Excellent Results

Bluebird Merchant Ventures (EPIC: BMV), the Asian focused resource development group is pleased to announce results relating to ongoing metallurgical test work conducted on an ore sample from Adit 4 at the Gubong mine. 


  • Excellent results from vat leach metallurgical test work
  • Recoveries of over 90% of the gold using conventional and alternative lixiviants
  • Vastly improved gravity recovery possible
  • Reduced operating and capital costs of future processing plant

Additional test work carried out on the Gubong oxide sample using a simple process known as vat leaching yielded recoveries more than 90% (up to 97%).  Vat leaching is a well-known and cost-effective processing route, whereby crushed or uncrushed ore is placed in a series of containments known as vats and irrigated with a solution to recover the desired metal into solution. The process may be highly mechanised, reducing the cost of labour and as there is no requirement for milling (reduction of ore in size to a powder), greatly reducing power consumption.

As the leached and washed ore is of coarse size, it may be readily used as a back-filling material or sold as aggregate.

Additional test work using enhanced gravity separation have yielded gold recoveries of around 70% into 3% of the mass. Simply put, this means that using just a gravity process on 100 tons of ore, 70% of the gold can be captured in just 3 tons of concentrate.  The remaining 30% of gold in 97 tons can be stockpiled for later processing. Additional test work will be conducted to further optimise gravity recovery as a potential processing route.

A sample of Gubong tailings (material that has been processed during previous operations), has been received and is being subjected to preliminary diagnostic tests. Results to date indicate recoveries of over 90% are possible from a head grade of 1.1 g/t gold.  Reprocessing of old tailings albeit at lower grade than mined ore, is cost effective as there is little cost involved in the reclamation of such tailings.

Additional samples will be obtained at a later date from other areas of the mine to verify the results obtained from those conducted on the oxidised sample obtained from Adit 4.

Colin Patterson, CEO, commented:

“We are very pleased with the rates of gold recovery presented at Gubong, with conventional and alternative lixiviants providing recoveries of up to 97%. As mentioned in a previous announcement released on 9 May 2018, metallurgical test work is a critical factor in determining the viability and economics of any mining project as well as for the optimisation of ongoing operations.

“These encouraging results evaluated to date provides us with great confidence that the ore is not problematic and does not require complicated or expensive extraction techniques. This will allow the Company to consider in its feasibility low cost options for the design and construction of its processing plant.

“Ore samples from the Kochang mine are currently being selected for metallurgical test work and we look forward to updating the market with results from these tests in due course”.


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