VANCOUVER, BRITISH COLUMBIA--(CCNMatthews - July 20, 2006) - Baja Mining Corp. (the "Company") (TSX VENTURE:BAJ) is pleased to provide summary results from the mine trial tests completed at its El Boleo copper/cobalt/zinc/manganese deposit ("Boleo"), Baja California Sur, Mexico in June 2006.
The principle Boleo property consists of 15 contiguous mineral concessions covering 9,255 hectares. The project includes three surface land tracts totaling 6,693 hectares covering all known mineral resources. The Company also owns 100% of an additional 8,783 hectares of exploration rights to the south of Boleo.
The 530 million tonne(i) global deposit of copper-cobalt-manganese-zinc mineralization at Boleo occurs within widespread, stratiform clay-rich horizons, or beds, known as "mantos" that average nearly 2 meters in thickness and outcrop along the canyon walls throughout the property. The commercial feasibility of underground mining at Boleo depends on favorable ground behavior combined with productive, high resource recovery mining methods similar to those used by the coal mining industries of North America, Australia, and South Africa.
As part of the Definitive Feasibility Study ("DFS") at Boleo the Company retained Australian Mine Design and Development Pty. Ltd. ("AMDAD"), along with Agapito Associates Incorporated ("AAI") of Golden, Colorado, USA, to design and supervise the tests aimed at defining productive and safe mining methods, as well as to provide geotechnical and operational information to guide design of a full scale underground mine capable of producing over 2.5 million tonnes of ore per year.
The primary objective during test mining was to confirm the geotechnical feasibility of underground mining at Boleo. Further, as a consequence of AAI's extensive experience in underground mining of soft-rock, bedded deposits, it was requested that their report also address and provide recommendations on key operational issues identified during this evaluation.
To achieve the above, AAI and AMDAD personnel: (1) reviewed pre-existing geological, geotechnical and operational documents and publications on Boleo; (2) inspected historical mine sites and openings ; (3) developed and implemented a geotechnical monitoring program for the test mine; (4) documented geotechnical and operational observations during and after test mining; and (5) collected and tested geotechnical core samples of the ground surrounding the test mine to assist in determining its physical properties.
The testwork was designed to monitor the variety of rocks in the roof of the test mine which included clay mantos, breccias and sandstones. The span of the roof from sidewall to sidewall varied along the length of the access drift and crosscuts, but in most locations was less than 4.5m.
The test mine workings were excavated to 150m from the surface portal site. A previously existing narrow drift parallel to the excavated main drift was rehabilitated and used for access to the mine. Five crosscuts were excavated off the left side of the main access drift. The furthest crosscut from the portal was dedicated as the geotechnical monitoring crosscut while the remaining four crosscuts were designated for, and used as, retreat mining (pillaring) crosscuts.
Roof bolts were used as primary roof support for the test mine. Untensioned, fully resin-grouted, 2.1m-long, 22mm-diameter rebar roof bolts installed in 33mm-diameter drilled holes were used for roof reinforcement. Generally, four roof bolts were installed in a row through a steel strap, one meter apart in each excavated access drift or crosscut.
Standing ground support tested during mining included timbers, timber cribs and steel beams supported by timbers or steel legs. Timbers were set approximately 1m apart next to sidewalls in locations that required extra support to control rib sloughing. This style of mining relies on controlled collapse of the seam roof in the mined out areas. The broken rock in the collapsed zone takes the weight of the overlying strata in order to relieve the stresses in adjacent areas. Timber cribs were built to support the roof in old, single-entry historical mine openings which were encountered throughout the test mine. These cribs served their intended purpose with no reported failures. Finally, steel beams were installed to support the roof in locations where the miners believed additional roof support was required beyond installing roof bolts. AAI believed many of the installed beams were not necessary and this was corroborated by the fact some beams were later removed without consequence.
Based on the test mine activities at Boleo, observations and review of the data and information collected by AAI, the following preliminary geotechnical and operational feasibility conclusions for underground mining in the mantos were reached:
With appropriate and site-specific mine design, equipment selection, mine planning and operation execution:
1. Based on currently available information, the most appropriate mining methodology for underground mining the clay mantos and breccias at Boleo would utilize room-and-pillar mining with pillar removal similar to those practiced by the coal mining industries of North America, Australia and South Africa.
2. Room-and-pillar with pillar removal mining methods should approach production levels comparable in magnitude to similar operations in the coal mining industries of North America, Australia and South Africa.
- Longwall and shortwall mining methods are not suited for the conditions at Boleo as a consequence of (1) the extensive faulting which divides the mantos into relatively small, irregular-shaped districts and (2) the hard conglomerate floor that is difficult to cut.
The Company's senior project team are now incorporating the mine trial results and recommendations made by AMDAD and AAI into the design of the underground mine openings and selecting the equipment needed for successful high productivity and safe mining operations. The mine plan will be designed to supply over 2.5 million dry metric tonnes of ore per year to the process plant.
John Wyche, of AMDAD, a Qualified Person, has reviewed the technical disclosure contained herein and accepts responsibility for such disclosure.
ON BEHALF OF THE BOARD OF DIRECTORS OF BAJA MINING CORP.
JOHN W. GREENSLADE, PRESIDENT
(i) Preliminary Economic Assessment by Bateman Engineering Pty Ltd et al, August 12, 2005.
The statements made in this News Release may contain certain forward-looking statements. Actual events or results may differ from the Company's expectations. Certain risk factors may also affect the actual results achieved by the Company.
FOR FURTHER INFORMATION PLEASE CONTACT:
Baja Mining Corp.
(604) 629-5228 (FAX)