Interim Update on test miningBaja Mining Corp. is providing an interim update on the test mining program currently under way on site at El Boleo copper-cobalt-zinc-manganese project in Santa Rosalia, Baja California Sur, Mexico. John Wyche, mine designer for the El Boleo project test mine, of Australian Mine Design and Development (AMDAD), provides the following update.
The underground mining trial at the El Boleo copper-cobalt project is now well advanced. The period leading up to Christmas 2005 was spent in developing access to the area where the room and pillar mining trial will be conducted. Over 180 metres of roadways have been driven and the workings are now 70 metres vertically below surface. Work is currently progressing on the first pillar mining panel which will reach over 100 metres depth. Drives are being mined around the pillar area to allow installation of geotechnical monitoring instruments. These will measure movements in the strata as the pillar area, which measures 45 metres by 30 metres, is extracted and the roof collapses into the mined-out void. Geotechnical planning and monitoring are being carried out by Agapito Associates, Inc. from Grand Junction, Colo. Agapito Associates will use information gathered from the trial to model the likely conditions in a full-scale production mine at Boleo.
The development drivage to date has already added significantly to an understanding of how modern, high-production mining methods can be applied at Boleo. Positive outcomes so far include:
* confirmation that the mineralized unit (copper, cobalt, zinc and manganese) is easily cut by the road header. Initial indications are that even lightweight continuous miners should be able to achieve high cutting rates;
* the miner produces no dust as he or she cuts so there should be no need for water sprays which may have caused problems in the clay-rich copper horizons;
* the workings have passed through numerous voids and stope-fill areas from the old mine workings. These areas did not present any greater mining difficulty than the virgin areas so initial indications are that the old mine workings will not create undue mining problems; and
* some roof stability problems were encountered but these allowed the geologists to gain a detailed understanding of the structures in the immediate roof. Roadway No. 2, and support designs and procedures were modified and the changes are providing stable workings.
Pillar extraction is due to commence in the last two weeks of January and will continue through to the end of February.
The company is proceeding to completion of a definitive feasibility study (DFS) under the direction of Bateman Engineering Inc. Canada, with anticipated completion in mid-2006. The DFS is investigating the viability of the underground mine producing 2.6 million dry tonnes per year of run-of-mine ore which will be processed through a hydrometallurgical processing plant to recover up to: 50,000 tonnes per year (tpy) of LME-grade (or better) copper; 2,100 tpy high-purity cobalt metal; and 10,000 tpy of contained zinc as zinc sulphate. Investigations are continuing on potential recovery of 35,000 tpy to 65,000 tpy of contained manganese, probably as manganese carbonate.
John W. Greenslade, PEng, president of the company and a qualified person, has reviewed the technical disclosure contained herein and accepts responsibility for such disclosure.