San Miguel yields high zinc values in soils

Soil sampling on the wholly owned San Miguel property in central Mexico’s San Luis Potosi state is returning exceptionally strong base metal values for Playfair Mining (PLY-V).

All but one of 25 soil samples taken over a 1,500-metre distance across the E1 North anomaly exceeded 1,000 parts per million (ppm), or 0.1%, zinc. Fourteen of these samples showed values greater than 5,000 ppm (0.5%) zinc and five are more than 1% zinc, with a maximum value of 5.7% zinc. Lead, copper and silver values are also high, peaking at more than 10,000 ppm (1%) lead, 4,529 ppm (0.45%) copper and 120.5 ppm (120.5 grams per tonne) silver.

Grid soil sampling is defining the limits of the El North anomaly, which sits 1.6 km north of the E1 South anomaly. The central portion of E1 South covers an area measuring 1,700 metres north-south and which averages 500 metres wide. All but one of the 103 soils collected in the central portion exceeded 5,000 ppm zinc. Values for all 103 samples ranged from 2,940 to 58,000 ppm zinc, 2,189 to greater than 10,000 ppm lead, 394-4,800 ppm copper and 11.7-94.1 ppm silver.

The property is in the Altiplano region. Mined since the 16th century, it hosts several carbonate replacement-type deposits. Charcas, one of Mexico’s largest underground zinc mines, is 15 km northwest of the E1 anomalies. It has produced some 35 million tonnes of ore grading 4.5% zinc, 0.32% lead, 0.26% copper and 67 grams silver. Published reserves in 1999 stood at 12 million tonnes of a similar grade.

Much of the region is a high plateau characterized by basin and range geography that varies from broad-open plains punctuated by sparse low mountain ranges in the west to terrain marked by abundant low mountains in the southeast.

Playfair (formerly known as Layfield Resources) optioned the Nicolas North and Concepcion properties in March 1999. The junior paid $10,000 cash and issued 2.7 million pre-consolidation shares for a 100% interest. The vendor, Ram Explorations Mexico, had originally blanket-staked 9,738 sq. km of ground covering large areas of alluvium-filled valleys, following the 1997 discovery of the San Nicolas volcanogenic massive sulphide deposit by Teck (TEK-T) and Western Copper Holdings (WTC-T). Playfair subsequently reduced its holdings to an aggregate 901 sq. km and called the land package San Miguel.

Working on the premise that many of the base metal mines in the Altiplano region are carbonate-replacement-type deposits associated with skarn-bearing, intrusive-contact systems, Playfair carried out regional grassroots sampling using mobile metal ion (MMI) technology. This analytical method detects small quantities of metallic ions and is often used in the search for deeply buried mineralization overlain by sterile or manmade cover (the Altiplano region is covered with overburden).

In central and northern Mexico, the carbonate replacement deposits are typically associated with early-to-mid-Tertiary intrusions, which are 0.5-2 km in diameter, range in composition from diorite to granite, and usually possess magnetic high signatures. The carbonate replacement deposits are structurally controlled and often associated with various proximal-to-distal low-grade alteration haloes.

During 1999 and 2000, Playfair carried out a field evaluation of published government airborne magnetic anomalies and completed MMI surveys on the edges of the most promising targets. MMI sampling lines were normally run in east-west pairs at 1-km spacing. Samples were collected every 250 metres at 20-cm depths using a plastic shovel.

The reconnaissance sampling revealed several priority targets, mostly in the southeastern part of the land package, within 20 km of the 4,500-tonne-per-day Charcas base metal mine.

Generally, an individual element response ratio of greater than 10 or 20 times background is considered anomalous. In the case of anomaly E1, four MMI soil lines at 1-km spacing targeted the eastern flank of a moderate magnetic high. The lines were run over a wide alluvial valley in tight desert bush. Playfair says three of the sample lines were “extraordinarily” anomalous, both in size and magnitude, for copper, zinc and lead. Anomaly E1 returned response ratios ranging from 273 to 87,500 times background. Select analysis for gold and silver also returned high values.

The peak values of anomaly E1 occur 1 km west of a north-south-trending railroad, which passes through the eastern edge of the anomaly. There are no other cultural features reported on these lines.

Playfair is led by Neil Briggs, as president, and Donald Moore, a director. Last fall, the junior rolled back its shares on a 1-for-5 basis.