TORONTO, ONTARIO--(Marketwire - 05/31/10) - MacDonald Mines Exploration (TSX-V:BMK - News) ("MacDonald" or "the Company") announces that the 2010 exploration drilling program on its McNugget Property has discovered new volcanogenic massive sulphide (VMS) mineralization of substance. Preliminary assays are reported below with follow-up full assays pending and will be reported when received. An analysis of technical data completed in February 2010 found magnetic and electromagnetic ("EM") targets that were not previously explained. During the May portion of the 2010 drilling campaign, a Crone Geophysics' down-hole EM system was used for drill target control - it has been established that McNugget VMS horizons show strongest conductivity where copper (Cu) content is highest.

Matagami-type VMS Camp on McNugget Possible

Hadyn R. Butler, P.Geo. has been retained to consult based on his extensive knowledge of the producing nickel (Ni) and VMS mines. Mr. Butler has over 44 years of geological experience with over 30 years consulting experience with INCO and has enjoyed substantial success in mineral exploration.

Mr. Butler notes, "Regionally, McNugget has three VMS mineralized greenstone fold limbs (to the north, west and southeast - likely the same stratigraphic suite) all of which have now yielded VMS mineralization over a potential cumulative strike length of approximately 20 km. A new VMS camp with characteristics similar to those seen at Matagami or Noranda in Quebec is now conceivable (i.e., larger VMS deposits with satellite deposits along strike)."

On the north fold limb, a fence of 5 new diamond drill holes has intercepted Cu-rich VMS along a strike length of approx. 1 km (still open along strike and to depth) with preliminary assays of greater than 1% Cu. Drill hole MN-10-90 had a greater than 4.5m intersection with a greater than 1% Cu zone, and drill hole MN10-102 a 15m greater than 1% Cu zone (1% is the limit of the preliminary assay technique used). This greater than 1 km zone also has strong zinc (Zn) values.

A second VMS target at the nose of the north and west fold limbs appears to be a plunging Zn-Cu-rich VMS body. Drill hole MN10-104 cut spectacular 10cm wide bands of sphalerite (Zn sulphide) throughout a 30m wide massive sulphide horizon. Drill hole MN10-112 (assays pending) was drilled along strike and at a greater depth to the east (approximately 100m) on this body. Field analysis of drill core suggests a potential VMS feeder zone in the vicinity.

Massive Sulphides Intersected in all Drill Holes

Massive sulphides were intersected in all May 2010 drill locations with widths varying from 2m to greater than 30m. One of the drill sites (two holes) on the McNugget Property intersected massive magnetite as well as associated ultra mafic materials. This location is characterized by a long magnetic high (magnetite) with an associated electromagnetic conductor (VTEM). These characteristics are very similar to those of the Freewest/Cliffs chromite discovery. The core from these two intersections is currently being tested for chromite. Additional geophysics will be planned along this long trend (1.5 kilometres) to aid in interpreting the potential of this zone to host chromite.

Big Mac Property

MacDonald's February 2010 re-interpretation created an initial program of 5 high-priority high-resolution ground gravity survey transects for both chromium (Cr) and nickel-copper (Ni-Cu) mineralization. Transect models were based directly on known mineralization signatures discovered within the "Ring of Fire". The Company's claim block contains both discrete and strike-extensive coincident airborne magnetic-VTEM and gravity anomalies within stratigraphically favorable geological packages with geophysical signatures similar to the significant Cr discoveries of Freewest and KWG-Spider near McFaulds Lake. Three gravity drill targets all exhibited anomalous densities coincident with local magnetic trends and have been interpreted to be steeply plunging dense bodies. Drilling was completed on one these targets in April 2010. Assays are pending. One of the gravity transects identified a density anomaly coincident with a discrete conductivity (VTEM) anomaly and offset magnetic feature that will be drill investigated for nickel.

Hulbert-Salo Property Exhibits Voisey's Bay-type Targets

MacDonald is designing an exploration program for its highly prospective Hulbert-Salo Property which appears to host an intact intrusive complex with potential for Voisey's Bay-type targets, as interpreted by Dr. Larry Hulbert. The Company's airborne geophysical survey (VTEM) outlined very conductive, discrete targets within a layered magnetic structure. The high conductivities observed are typical of magmatic massive sulphides containing nickel. To optimize the Company's chances of success, a surface time domain geophysical survey is being designed that will focus on the potential nickel targets. A Crone Geophysics' system will be used in the event that other more conductive (superconductors) and/or deeper targets were not detected by the airborne survey.

Exploration to Recommence June 2010

The next phase of exploration will commence in late June 2010. MacDonald believes that there is potential for its James Bay properties to host both Nickel and Chrome on the McNugget, Big Mac and Hulbert/Salo Properties.

As the assays become available, 3D target modeling will be based on assays, geology, magnetic susceptibility, conductance and so forth. Further drilling will provide greater detail on three selected VMS targets as well as the strongest potential Ni-Cu targets. It is anticipated that deeper drilling will be required to test the high conductance targets mapped by the geophysical programs used during May.

KWG's declaration that the consultation process with the First Nation Communities regarding their proposed railway would be best conducted if they were able to first accumulate the needed information in which to have a knowledgeable consultation is echoed by MacDonald. It is the Company's belief that the responsible way to proceed with a first-time drill program on the Hulbert-Salo Property would be to first collect information so that the Company could then have a fully informed consultation relating to drill targets, drilling procedures and utilization of personnel from the local communities to assist in those efforts, prior to commencing drilling activity in any new area. Through this collection phase, the Company will do everything possible to maintain the same respect for the environment it has shown throughout James Bay and perform this work with the smallest footprint possible. MacDonald's previous and current exploration activities have all been conducted on and in areas surrounding its McNugget and Big Mac properties where the Company has signed an agreement with the First Nations community of Webequie, and continues to have a strong working relationship with the Community.

The completion of the first phase of drilling has provided MacDonald with considerable insight into target modeling and selection and this will be very valuable as the Company moves to drill the Nickel targets.

 

Drill Program Highlights & Results

Preliminary assay results of MN10-102 (over-detection-limit
results are pending)

Hole_ID     From      To   Sample_ID    Cu_ppm    Zn_ppm
greater
than
MN10-102   24.00   25.00      315004      5420     10000
greater
than
MN10-102   25.00   26.00      315005      6610     10000
greater
than
MN10-102   26.00   27.00      315006     10000      9030
greater
than
MN10-102   27.00   28.00      315007     10000       333
MN10-102   28.00   29.00      315008      5980       343
MN10-102   29.00   30.00      315009      6740       417
greater
than
MN10-102   30.00   31.00      315011     10000       456
greater
than
MN10-102   31.00   32.00      315012     10000       360
greater
than
MN10-102   32.00   33.00      315013     10000       235
greater
than
MN10-102   33.00   34.00      315014     10000       205
greater
than
MN10-102   34.00   35.00      315015     10000       418
greater
than
MN10-102   35.00   36.00      315016     10000       282
greater
than
MN10-102   36.00   37.00      315017     10000       209
MN10-102   37.00   38.00      315018      5820       164
MN10-102   38.00   39.00      315019      8540       267
MN10-102   39.00   40.00      315021      3840       185


Preliminary assay results of MN10-104 (MN10-112 has assays pending)

Hole_ID      From       To   Sample_ID   Cu_ppm   Zn_ppm
MN10-104   172.00   173.00      315097     1220    51700
MN10-104   173.00   174.00      315098      365    26100
MN10-104   174.00   175.00      315099      971    33000
MN10-104   175.00   176.00      315101      862    22500
MN10-104   176.00   177.00      315102     5520    19100
MN10-104   177.00   178.00      315103    10600    53100
MN10-104   178.00   179.00      315104     5670    36300
MN10-104   179.00   180.00      315105    19620    12100
MN10-104   180.00   181.00      315106     2660     1160


Highlights of the successful drill program include:

------------------------------------------------------------
Drill Hole #          Massive Sulphide Intersection (metres)
------------------------------------------------------------
MN10-92                                23.2
------------------------------------------------------------
MN10-102                               21.3
------------------------------------------------------------
MN10-95                                16.8
------------------------------------------------------------
MN10-111                               14.94
------------------------------------------------------------
MN10-112                               11.92
------------------------------------------------------------
MN10-91                                 8.2
------------------------------------------------------------
MN10-94                                 7.8
------------------------------------------------------------
MN10-87                                 5.3
------------------------------------------------------------
MN10-99                                 5.2
------------------------------------------------------------


Drilling to date is summarized in the following table:

----------------------------------------------------------------------------
Drill Hole #             UTM Northing   UTM Easting    Az   Dip   Length (m)
----------------------------------------------------------------------------
MN10-87                       5845026        515537   355   -78       271.27
----------------------------------------------------------------------------
MN10-88                       5844975        515565     0   -55       182.88
----------------------------------------------------------------------------
MN10-89                       5844975        515565     0   -75       204.91
----------------------------------------------------------------------------
MN10-90                       5845015        515290   350   -75        91.44
----------------------------------------------------------------------------
MN10-91                       5845015        515290   350   -45       146.91
----------------------------------------------------------------------------
MN10-92                       5845275        515460   n/a   -90        79.25
----------------------------------------------------------------------------
MN10-93                       5845275        515460     0   -45       106.68
----------------------------------------------------------------------------
MN10-94                       5844980        514850   350   -70       182.88
----------------------------------------------------------------------------
MN10-95                       5844850        513350   133   -65       134.11
----------------------------------------------------------------------------
MN10-96                       5845250        515485     0   -45       106.68
----------------------------------------------------------------------------
MN10-97                       5845235        515455     0   -45       114.30
----------------------------------------------------------------------------
MN10-98                       5844925        514862   350   -70       201.17
----------------------------------------------------------------------------
MN10-99                       5844925        514862   350   -60       182.88
----------------------------------------------------------------------------
MN10-100                      5845100        514853   170   -45       173.74
----------------------------------------------------------------------------
MN10-101                      5845100        514853   170   -60       219.46
----------------------------------------------------------------------------
MN10-102                      5845040        515112   335   -65        70.10
----------------------------------------------------------------------------
MN10-103                      5844880        513330   192   -65       192.20
----------------------------------------------------------------------------
MN10-104                      5844880        513330   115   -65       234.70
----------------------------------------------------------------------------
MN10-105                      5845025        515715   335   -65       106.68
----------------------------------------------------------------------------
MN10-106                      5845025        515715   335   -80       122.00
----------------------------------------------------------------------------
MN10-107                      5841658        519030   170   -63       155.45
----------------------------------------------------------------------------
MN10-108                      5841658        519030   135   -60       124.97
----------------------------------------------------------------------------
MN10-109                      5838468        515188   n/a   -90       146.30
----------------------------------------------------------------------------
MN10-110                      5838437        515220   300   -62       195.07
----------------------------------------------------------------------------
MN10-111                      5840240        512900    90   -65       124.97
----------------------------------------------------------------------------
MN10-112                      5844910        513375   115   -65       304.80
----------------------------------------------------------------------------

----------------------------------------------------------------------------
TOTAL                                                                4471.46
-------------------------                                         ----------

On-site Quality Assurance/Quality Control Measures

All diamond drill (half core) samples were collected and sealed on site and shipped under chain of custody supervision to the ACTLABS sample preparation laboratory in Thunder Bay, Ontario. Analyses are performed by ACTLABS laboratories (ISO/IEC 17025 certified) either in Ancaster or Thunder Bay, Ontario. All core samples were selected by the MacDonald Mines qualified site geologist, and were cut in half on site by diamond saw. For security, the remaining half core was then resealed in the original core boxes. Individual half core samples were labelled, placed in plastic sample bags and sealed. Groups of samples were placed into sealed and durable rice bags then shipped out by air transport. Remaining coarse reject portions of all samples remain in storage at the ACTLABS preparation laboratory storage facility at Thunder Bay.

Independent Quality Assurance and Quality Control Protocol

A QA/QC program has been implemented to monitor all assays from the current drilling program. Samples are assembled as batches and are continuously shipped from the site for immediate testing. Included in each batch of samples are certified reference standards (every 20 samples) and blank samples comprised of sterile drill core placed in at random locations (every 20-30 samples).

Quentin Yarie, P.Geo, Vice President of Exploration is the qualified person for the technical data contained within this report.

About MacDonald Mines Exploration Inc.

MacDonald Mines is a mineral exploration company with an established history in the exploration of gold and base metals. MacDonald has set upon a strategic direction of exploration in the Canadian Northlands, with particular focus on the "Ring of Fire" in James Bay, Ontario, its joint-venture with Virginia Mines in Quebec and now the LaRonge area in Saskatchewan.

More detailed information is available on the website at http://www.macdonaldmines.com/.

Cautionary Statement:

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.

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.