TORONTO, ONTARIO--(Marketwired - Aug 30, 2017) - MacDonald Mines Exploration Ltd. (TSX VENTURE:BMK) ("MacDonald Mines", the "Company", or "BMK") announces that it has received gold and silver assays on 6 trenches across the Oxide Sands zone. Trenches 725, 750, 775, and 825 produced positive gold (Au) and silver (Ag) results.

Table 1 highlights the recently received results from the on-going sampling. The spatial relationship between these trenches and the Oxide Sands trend is shown in Figure 1.

Table 1: Highlights from on-going Oxide Sands trenching and sampling

To view Figure 1, please visit the following link: http://media3.marketwire.com/docs/bmk0830fig1.pdf.

Quentin Yarie, President and Chief Executive Officer of MacDonald Mines stated, "Our exploration program continues to expand the lateral extents of the Oxide Sands. Our trenching has uncovered new gold horizons within the Oxide Sands that expand the width of the precious metal footprint and indicate that the gold and silver inventory of the Oxide Sands at the Wawa-Holdsworth Project may be larger than initially anticipated."

Gold distribution in the "Oxide Sands" formation

The current trenching program is indicating that gold and silver in the soil formation are not solely distributed in the "black sands" layers as they are also found in soils ranging in colour from green-grey to orange and brown. The precious metal enrichments of this soil formation is possibly more widespread than initially anticipated as gold and silver enrichments appear not be restricted to purely the "black sands".

No significant results for precious metals were detected in trenches TR-800 and TR-850. TR-800 crosses a road where only disturbed material (road fill) was encountered. For TR-850, assays are still pending for nine stations along the trench where it encounters the favorable EM anomaly that is associated with the auriferous zones of the Oxide Sands formation.

Oxide Sands Sampling Procedure

The Oxide Sands samples are sampled like a borehole at systematic 1-metre intervals along the trenches. Overburden is not sampled - if the sands are exposed, they are sampled vertically along the wall of the trench in 2 to 3kg bags. Oxide Sands samples are not grab samples (see Schematic below).

To view the schematic, please visit the following link: http://media3.marketwire.com/docs/bmk0830planview.pdf.

Wawa-Holdsworth Project Highlights

• Neighbouring Richmont's Island Gold Mine, Argonaut's Magino Gold Project and Goldcorp's Borden project
• Numerous gold showings with diversified mineralization styles occurring in a 500 metres-wide deformation corridor
• Year-long road access and easy access to rail, road, electrical power, labour force and suppliers

Overview of the Wawa-Holdsworth Project

Historic work by previous operators defined three gold targets on the Wawa-Holdsworth Project:

• Greenstone-hosted quartz-carbonate vein deposit (Soocana Vein System and Reed-Booth Showing);
• BIF-hosted gold deposits (gold-bearing pyrite zones in an Algoma-type iron formation);
• Gold-bearing Oxide Sands developed from the weathering of the auriferous pyrite zones.

MacDonald Mines is focusing its near-term exploration program on the Oxide Sands. These appear to extend for more than 2 kilometres on the property as corroborated by MacDonald's recent airborne magnetics results (see June 1, 2017 News Release) and reach a depth of at least 8 metres.

Positive preliminary metallurgical results (see July 11, 2017);

• The concentration ratio of gold in rougher flotation averaged 6.0:1
• The concentration ratio of silver in rougher flotation averaged 5.2:1
• Reduction of feed volume in rougher flotation by approximately 85-90%
• The Oxide Sands can be processed by a simple crushing/flotation process
• No caustic treatments are necessary
• The processing will require low power requirements
• The waste material is inert (>70 percent silica/quartz)

The soft and relatively unconsolidated Oxide Sands material can be extracted like an aggregate. The Company is working to better define the Oxide Sands in preparation for their potential extraction.

On-site Quality Assurance/Quality Control ("QA/QC") Measures

Sand samples were transported in security-sealed bags for analyses to Activation Laboratories Ltd. in Ancaster, Ontario. Individual samples are labeled, placed in plastic sample bags and sealed. Groups of samples are then placed into durable rice bags and then shipped. The remaining coarse reject portions of the samples remain in storage if further work or verification is needed.

MacDonald Mines has implemented a quality-control program to comply with best practices in the sampling and analysis of both the Oxide Sands and drill core. As part of its QA/QC program, MacDonald Mines inserts external gold, silver and Pt and Pd standards (low to high grade) and blanks every 20 samples in addition to random standards, blanks, and duplicates.

Qualified Person

Quentin Yarie, P Geo. is the qualified person responsible for preparing, supervising and approving the scientific and technical content of this news release.

About MacDonald Mines Exploration Ltd.

MacDonald Mines Exploration Ltd. is a mineral exploration company headquartered in Toronto, Ontario focused on gold exploration in Canada. The Company has built a portfolio of safe-jurisdiction, infrastructure-rich projects that demonstrate the greatest market potential for return. The Company is aggressively advancing its highly prospective Wawa-Holdsworth Project.