TORONTO, Nov. 28, 2017 (GLOBE NEWSWIRE) -- MacDonald Mines Exploration Ltd. (BMK.V) ("MacDonald Mines", the "Company", or “BMK”) announces that it has received gold and silver assays for most of the remaining trenches across the Oxide Sands zone. Trenches 650, 675, 700, 775S, 1200, 1250, 1250SE, 1400 and 1700 all 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.

A  map accompanying this announcement is available at http://www.globenewswire.com/NewsRoom/AttachmentNg/f33d87bf-52b9-482c-8bec-825b5cbe0b14

Quentin Yarie, President and Chief Executive Officer of MacDonald Mines stated, "The trenching of the Oxide Sands has resulted in very positive findings.  It not only confirmed that they extend on surface over a strike length of 1100m but also, that we’re dealing with higher grades than anticipated. Assay results with up 8.94 g/t gold are very encouraging and we expect the assay results from our sonic drilling campaign to corroborate these findings.”

Next Steps for the Wawa-Holdsworth Project

Oxide Sand resource estimation
The Company is currently awaiting assay results for 401 holes drilled during its 2,000 m sonic drilling program. Once results are made available, the Company will initiate a NI43-101 inferred resource estimation for the Oxide Sands. Assays for sonic drilling are taking longer than expected due to the necessity to dry the unconsolidated materials before mixing.  Unlike crushing hard rock samples where the moisture content is minimal, these drill cores are saturated and prepping them is a much longer process.

Lode gold exploration at the Reed-Booth Showing
In addition to the Oxide Sands, MacDonald Mines continues to investigate the lode gold potential on the property.  The Reed Booth Showing is a target for high-grade gold mineralization at the Wawa-Holdsworth Project and the Company is awaiting the results of its channel sampling program announced on Nov. 9, 2017.

Regionally, structures parallel to the one hosting the Reed-Booth Showing, host some of the historic high-grade mines of the Michipicoten Greenstone Belt. This includes the Edward Mine (144,000 ounces of gold at 11 g/t) located 28 km NE, and the Minto Mine South Zone actively explored by Red Pine Exploration (historic Minto Mine produced 22,000 ounces of gold at 12.56 g/t gold) located 18 km SSW. The reader is cautioned that the gold mineralization present at the Edward Mine and in the Minto Mine South Zone is not necessarily indicative of mineralization on the Company’s Wawa-Holdsworth property.

Overview of the Wawa-Holdsworth Project

• Neighbouring Alamos' 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

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. Assays results received so far indicate that the precious metals-rich sand formation occurs over a 1.1 km strike length, but Oxide Sands were also observed in the trenching and drilling west of line 1700.  Pending assay results, the favourable soil formation containing the Oxide Sands may have an overall strike length of approximately 1.7 km. This will corroborate MacDonald’s interpretation of the geophysical anomalies obtained by the MAX-MIN survey conducted earlier this year (see July 6, 2017 News Release).

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’s trenching and sonic drilling programs completed earlier this fall were designed 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, platinum and palladium standards (low to high grade) and blanks every 20 samples in addition to random standards, blanks, and duplicates.