Minefinders boosts Dolores (October 18, 1999)

Toronto-listed Minefinders (MFL-T) has arrived at a new resource estimate for its wholly owned Dolores gold-silver property in Mexico’s Chihuahua state.

Using a cutoff grade of 0.3 gram, Minefinders outlined a measured, indicated and inferred resource of 88.9 million tonnes grading 0.75 gram gold and 42.8 grams silver per tonne. Using a cutoff grade of 5 grams, the resource is 3.1 million tonnes grading 4.3 grams and 266.37 grams silver. The company says the higher cutoff is more representative of the geology.

The estimate is equivalent to a contained resource of 2.1 million oz. gold and 122.2 million oz. silver. The revised resource model is based on 197 drill holes spanning 1.9 km.

Comprising more than 400 sq. km, the Dolores project is in the Sierra Madre Occidental Mountains, near the border with Sonora state. Between 1906 and 1929, the area produced 300,000 oz. gold and 14 million oz. silver.

By 1993, when Minefinders acquired an option to earn a 100% interest, the property had undergone little modern exploration and never been drilled.

Surface mapping and geochemical sampling revealed a north-northwesterly trending zone of mineralization extending for at least 4,000 metres along strike. The gold-silver mineralization is associated with the emplacement of north-southerly trending latite dykes along the contact between interbedded andesites and an agglomeratic tuff. The Dolores zone is described as a low-sulphidation deposit with gold mineralization related to brecciation and stockwork-veined volcanics.

Since September 1996, crews have completed 32,000 metres of core drilling in 136 holes and 23,500 metres of reverse-circulation drilling in 115 holes. Included in this total are 56 holes drilled by Echo Bay Mines (ECO-T) in 1997, during a short-lived period in which it held an option to earn a 60% interest. Minefinders re-acquired a 100% interest by paying $4 million in cash and surrendering 1.25 million of its shares to Echo Bay. The transaction increased to 25% Echo Bay’s ownership of Minefinders.

Drilling to date has tested 2,700 metres of strike, with most of the holes focused on a 1,900-metre length of the Dolores deposit.

In 1998, Mineral Resource Development Inc., estimated an indicated and inferred resource of 61 million tonnes grading 0.83 gram gold and 44.05 grams silver per tonne, equivalent to 1.6 million contained ounces gold and 86.3 contained ounces silver, using a cutoff grade of 0.5 gram gold-equivalent.

The 1999 resource estimate is based on the addition of 11 drill holes that were not available for the 1998 study, plus recent geostatistical analysis.

Minefinders has indicated that another 16,000 metres of drilling are required to move most of the indicated material into the measured category.