Dundee Sustainable Technologies Inc. Removes Arsenic From Gold Concentrate

MONTREAL, QUEBEC--(Marketwired - Sept. 15, 2017) - Dundee Sustainable Technologies Inc. ("DST" or the "Corporation") (CSE:DST)(CSE:DST.CN)(CSNX:DST) and Radisson Mining (TSX VENTURE:RDS) ("Radisson") are pleased to announce the results of a pilot scale metallurgical test program utilizing DST's arsenopyrite treatment approach, on a 5-tonne sample from Radisson's O'Brien gold project.

DST successfully removed 92.2% of the arsenic content and demonstrated, at the pilot scale, that the refractory parcel of O'Brien gold material can undergo a pre-treatment to remove arsenic and create a mineral concentrate with levels of arsenic that are acceptable to the market and traditional gold recovery circuits.

In February 2017, DST received 5 tonnes of representative material from the O'Brien gold project. The material was crushed and ground. The free gold was recovered by gravimetry and the balance of the material was concentrated through flotation. This approach mirrored Radisson's planned recovery circuit in the PEA. DST generated a gold concentrate which contained 109 grams per tonne of gold, 11.6% arsenic and 19.9% sulphur. Using's DST thermal decomposition in an oxygen deprived environment approach, the arsenic content was reduced by 92%, with no gold losses while leaving a sulphur content of 8%.

The arsenic depleted concentrate was treated for gold extraction using both DST's patented chlorination technology and cyanidation where gold recoveries of 94.6% and 93.5% were achieved, respectively.

The process was overseen by an independent consulting firm so that the piloting test program and results could be included in Radisson's future Preliminary Economic Assessment ("PEA").

Mario Bouchard, president of Radisson comments "For Radisson the DST's two new processes tested, neutralization of the arsenic by vitrification and recovery of the gold by chlorination, demonstrate economical and environmental advantages. We are pleased to collaborate with DST and we will consider seriously those two innovations in our development plans"

"These excellent piloting results demonstrate the efficiency of the arsenopyrite treatment approach developed by DST and, combined with the Company's arsenic stabilization technology, provides a cost-effective alternative to POX and offsets market penalties for complex arsenopyrite bearing deposits." says Brian Howlett, DST's President & CEO.

The Company continues the commercialization of its cyanide-free gold extraction and arsenic stabilization technologies. DST also provides its technical expertise and facilities to companies wishing to further evaluate the development of their projects using the Corporation laboratory, piloting and/or industrial demonstration facilities on specific projects in need of viable processing capacities, and to initiate engineering studies required for an industrial implementation.

The program, scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Jean-Philippe Mai, P.Geo. who is a "Qualified Person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101").

About Dundee Sustainable Technologies, a company controlled by Dundee Corporation

The Corporation is engaged in the development and commercialization of environment-friendly technologies for the treatment of materials in the mining industry. Through the development of patented, proprietary processes, DST extracts precious and base metals from mineralized material, concentrates and tailings, while stabilizing contaminants such as arsenic, which could not otherwise be extracted or stabilized with conventional processes because of metallurgical issues or environmental considerations.

DST has filed, published and was granted patents for these processes in several countries.

FORWARD LOOKING STATEMENTS: This press release contains forward-looking statements that address future events and conditions, which are subject to various risks and uncertainties. Actual results could differ materially from those anticipated in such forward-looking statements as a result of numerous factors, some of which may be beyond the Corporation's control. These factors include: general market and industry conditions, risks related to continuous operations and to commercialization of new technologies and other risks disclosed in the Corporation's filings with Canadian Securities Regulators.

Forward-looking statements are based on the expectations and opinions of the Corporation's management on the date the statements are made. The assumptions used in the preparation of such statements, although considered reasonable at the time of preparation, may prove to be imprecise and, as such, undue reliance should not be placed on forward-looking statements. The Corporation expressly disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise, except as required by applicable law.

Neither the CSE nor its Regulation Services Provider (as that term is defined in the policies of the CSE) accepts responsibility for the adequacy or accuracy of this release.