Old O’Brien gold mine
In 1924, the claims were staked by two prospectors for the M.J. O’Brien Company Ltd. and vein No. 1 was discovered by prospecting. The O’Brien mine was therefore discovered in 1924 during the first period of exploration in the region. In 1925, the No. 1 exploration shaft was sunk to a depth of 110 feet (33.5 metres) and a period of intensive exploration began. The main production shaft (shaft No. 2) was put into operation in 1930 and was deepened to 2,125 feet in 1934. Construction of an internal shaft was initiated in 1941 and completed in 1949. It extended to a vertical depth of 3,450 feet below surface. In 1933, the O’Brien mine went into production and was operated until 1956. From 1925 to 1956, the mine produced approximately 1,310,356 short tons of ore at an average grade of 0.448 ounces of gold per ton (RPA, May 2007). The mine was closed and the surface infrastructure was dismantled in 1957
In the early 1970s, the property was acquired by A.N. Ferris & Associés, which carried out a major drilling program and subsequently began to rebuild surface infrastructure. In 1977, Consolidated Goldfields Mining acquired a 51% interest in the project and Darius Gold Mine Inc. was created. The upper levels of the mine were then refurbished and a new mill, with a capacity of 200 short tons per day, was built in 1977–1978. Darius processed a total of about 141,500 short tons of ore at a grade of 0.12 oz/st before it closed in 1981 (RPA, May 2007).
Sulpetro Minerals (which became Novamin, then Breakwater and then Nyrstar) bought the property in December 1981, and renamed it the O’Brien Division. The initial interest was to acquire the mill to process ore from a contiguous property: Kewagama. In 1985, the O’Brien mine was flooded once again and geophysical surveys were carried out. In 1986–1987 a program of exploration drilling tested extensions east and west of the property and led to the discovery of 36E area located about 2,000 feet (610 metres) east of the main shaft of the old O’Brien Mine. In 1988, additional holes were drilled on 36E area.
Breakwater acquired Novamin in 1989 and drilled additional holes in this area, and then produced a first estimate of mineral resources. However, these resources were estimated before National Instrument 43-101 standards of disclosure came into force.
In 1994, Radisson obtained an option to acquire 50% of the O’Brien property. In 1999, the Company acquired 100% of the O’Brien property.
Old O'Brien area
As soon as the option agreement was signed in 1994, the Company commissioned geologist Jack Charlton, who worked at the O’Brien mine in the 1980s, to re-evaluate the resources of the old mine at the time it closed in 1981. (Source: Charlton, J.D., 1995 -O’Brien Re-evaluation for Radisson Mining Resources,1995). However, these resources were estimated before National Instrument 43-101 standards of disclosure came into force and as such should not be relied upon. An independent Qualified Person as defined in National Instrument 43-101 has not done sufficient work to classify the historical estimate as current mineral resources. Radisson is therefore not treating the historical estimate as current mineral resources or mineral reserves.
Historical inferred mineral resources (Charlton, 1995)
These “resources” are historical in nature and should not be relied upon. It is unlikely they conform to current NI 43-101 criteria or to CIM Standards and Definitions, and they have not been verified to determine their relevance or reliability. They are included in this section for illustrative purposes only and should not be disclosed out of context.
|Old O'Brien mine