Monument Announces Bioleaching Test Work Results on the Selinsing Sulphide Gold Project

VANCOUVER, BRITISH COLUMBIA--(Marketwired - Feb. 27, 2018) - Monument Mining Limited (TSX VENTURE:MMY)(FRANKFURT:D7Q1) "Monument" or the "Company" is pleased to announce the successful completion of a third programme of bioleaching testwork on flotation concentrate produced from the Buffalo Reef deposit in Malaysia.

Highlight of Bioleaching Testwork Result

The testwork was conducted at the SGS laboratory in Johannesburg under the management of Outotec BIOX® specialists. The batch testwork programme results showed that over 90% sulphide oxidation occurred after 9 days, 98% after 15 days and 99% after the full 24 days. The sulphide oxidation levels proved that representative samples of Selinsing/Buffalo Reef concentrates are amenable to the BIOX® process. No deleterious elements were found in the concentrate analysis and the batch tests confirmed that the sulphide to carbonate ratio was sufficient to be net acid generating. Cyanide leach tests on the 24-day BIOX^® residues achieved between 88% and 92% gold dissolution within 24 hours.

To date, extensive flotation testwork has been conducted by the Selinsing R&D team on all of the ore types at Selinsing and Buffalo Reef to determine the optimum suite of gangue depressants and has culminated in the design of the flotation plant featuring conditioning and rougher scavenger flotation followed by further conditioning and cleaner flotation. The flotation testwork employed industry-standard sulphide flotation collectors, auxiliary collectors, specialist gold recovery promoters and conventional frothing agents. Concentrate grades ranging from 5.9% to 14.2% sulphur have been produced in the flotation testwork with gold recoveries for the major ore types in the range of 87-95 %. Mass pull to cleaner concentrate varied from 6.5% to 15.8% and an overall 10% yield containing 6.1% sulphur has been used for downstream plant design.

The laboratory flotation testwork results have determined the required conditioning and flotation residence times for the rougher scavenger and cleaner flotation stages, enabling equipment sizing to be completed using industry standard scale up factors. The flotation plant will feature six rougher scavenger cells each of 50 cubic metres capacity and four cleaner flotation cells of 20 cubic metres. Cleaner tailings will be recycled to rougher feed. The flotation circuit will be designed to handle the varied response of the different ore types especially where the desired sulphur grade is achieved though rougher flotation only and the cleaner stage may be bypassed.