Thursday, February 16, 2012 MacDonald Mines Exploration Ltd. (TSX.V: BMK) (“MacDonald” or the "Company”) announces the mobilization of a geophysical crew to begin a ground gravity survey over the Company’s VMS, Ni and Cr targets on the Butler Property in the Ring of Fire.
The recently released Ontario Geological Survey ("OGS") and Geological Survey of Canada ("GSC") gravity gradiometer data over the Ring of Fire has been the catalyst for the Company’s renewed interest in the gravity technique as a proven exploration tool for identifying density variations associated with mineralization such as VMS, Ni and Cr. The conclusion of the OGS/GSC gravity gradiometer survey was that it was probable that gravity highs were defining the package of mafic and ultramafic intrusive and volcanic rocks which host the chromite mineralization.
The measurement of gravity is an effective technique for defining geometry, structure, and a proven tool in mapping intrusions in sedimentary and volcanic terrains. Alteration can also be mapped where geological units of different density are offset and/or altered. The use of ground gravity surveys, have historical success in the search for volcanogenic massive sulphide (VMS) deposits and has been attributed to the discovery of the Sunridge Gold Embra Derho deposit in early 2007 (Approx 62.5 m/tonnes) as well as satellite discoveries at Nevsun’s Bisha (Approx 40 m/tonnes) both in Eritea.
The Company initiated a detailed interpretation of the available public data over the known economic discoveries in the Ring a Fire (Cliffs Natural Resources, Noront Resources, etc.). Part of this process was the development of models for chrome and nickel. The models consist of geochemical, lithological and geophysical signatures. The attributes of the known discoveries in the area were compared to targets both on both our Butler and Sanderson properties with strong correlations.
The gravity data collected over the Butler property by the OGS - GSC gravity survey confirmed the Company’s interpretation of a large mafic – ultramafic package exists along the eastern portion of the property. The Company has drilled through and into some of the magmatic features to corroborate this interpretation. In 2011 drill hole V05 drilled through a mafic sill consisting of an upper portion made up of magnetite gabbros, magnetiites, and troctolites passing downward into Fe-rich peridotites with high background chrome concentrations. The hole was terminated in peridotites so the proportion of ultramafic materials in these sills is at least equal to or greater than the mafic material. Dr. Hulbert concludes that “The observed footwall ultramafic association to the overlying gabbroic rocks and the property wide distribution of these gabbroic bodies suggests property wide favorability for ultramafic bodies which host Ni-Cu-PGE and chrome deposits.“
Map 1. Magnetic map (TF) of Butler showing the gravity gradiometer anomaly (inversion) associated with the eastern mafic ultramafic package.
The presence of a density anomaly associated with an ultra-mafic sequence would suggest the presence of a different rock type of greater density (chromite, magnetite) or the presence of sulphides which are also extremely dense. These are the same characteristics identified over the main chromite deposits (Blackbird, Big Daddy, Black Creek, Black Label and Black Thor).
Ground Gravity Survey
While the OGS/GSC gravity gradiometer survey would not likely have the resolution to define the known deposits in the Ring of Fire, a ground survey offers much greater resolution. Ground gravity data will be collected over Butler 3, 4 and 5. At Butler 3 the objective of the survey is to confirm the presence of a density anomaly coincident with the EM and magnetic target. Butler 3 remains the primary target and the field work will begin there.
At Butler 3, a density anomaly associated with the other geophysical techniques would add credence to the interpretation of a large inverted VMS system. This system is associated with the stringer materials intersected in diamond drill hole BP11-Cu06 which intersected 167 metres of 0.39% Cu and 1.13% Zn. Butler 3 exhibits the following characteristics:
- The volume of alteration is exceptional, indicating that a very large volume of hydrothermal fluid discharged in this region
- Butler 3 is contained in an overturned felsic-dominated sequence
- The alteration zone is Cu-enriched, and the Cu content increases stratigraphically upwards (but structurally downwards) towards the mineralized horizon. Cu tenor is high (greater than 3%)
- Immediately overlying the marker horizon, massive sulfides have been discovered at Butler 3, and it’s the down-dip extension of these that may contain the larger massive sulfide zone which should exhibit a gravity anomaly
The ground gravity survey is being conducted by Abitibi Geophysics and is expected to be completed in February, 2012. A drill program will follow upon completion of the survey and an interpretation of the results.
Quentin Yarie, P.Geo., is the qualified person in regard to the technical data contained within this news release and will be responsible for overseeing all aspects of the Company’s exploration programs.
About MacDonald Mines Exploration Ltd.
MacDonald Mines is a mineral exploration company with an established exploration history in the Canadian Northlands. MacDonald Mines has set upon a strategic direction of exploration with particular focus on nickel, chrome, copper, zinc, vanadium and titanium in the “Ring of Fire” area of the James Bay Lowlands of Northern Ontario.
With over 9 years of exploration in the James Bay Lowlands, the Company has systematically acquired quality land positions based on a very precise selection format that utilizes region-wide interpretations completed by geological consultant Hadyn Butler, P. Geo. MacDonald is now the second largest landholder in the Ring of Fire and has a proven track record of environmentally and socially conscious exploration practices.
MacDonald Mines exploration focus has been on 3 properties - the Butler, the Semple-Hulbert and the Sanderson. Recent exploration has been focused on the Butler property, where the Company has identified seven significant zones of multi-element mineralization, including copper-zinc VMS systems, vandiferous titano-magnetite and magmatic nickel sulphides.
The Company has established rapport with First Nation Communities in this region, which has culminated in the signing of exploration agreements with the Kasabonika Lake and Webequie First Nations
More detailed information about the Company is available on the website: www.macdonaldmines.com
Brent Nykoliation, Vice President of Business Development
Phone: (416) 364-4986, (416) 364-2753 (FAX)
Kirk McKinnon, President & CEO
Phone: (416) 364-4986, (416) 364-2753 (FAX)
Cautionary Statement: Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein. The foregoing information may contain forward-looking statements relating to the future performance of MacDonald Mines Exploration Inc. Forward-looking statements, specifically those concerning future performance, are subject to certain risks and uncertainties, and actual results may differ materially from MacDonald Mines plans and expectations. These plans, expectations, risks and uncertainties are detailed herein and from time to time in the filings made by MacDonald Mines with the TSX Venture Exchange and securities regulators. MacDonald Mines does not assume any obligation to update or revise its forward-looking statements, whether as a result of new information, future events or otherwise. We seek safe harbour.