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The Alluvial Gold Properties

The Geology

Variegated schists, amphibolites and quartzites form rugged hills capped by laterite and intruded by dolerites. Certain areas are overlain by a white sands formation. Hornblende biotic gneisses form a large complex group south of Oko Mts. Gold is associated with Barama-Mazaruni assemblage. Alluvial deposits of Cuyuni river are ~15 m. deep and are mineralized with fine gold from top to the bedrock.

An overall alluvial gold grade in Matope-Arawak creek (draining Oko Mts. into Cuyuni river, above the properties) is above 1 g/m³. Gold is in small chips and is stained with limonite. Its source is an extensive complex of large quartz formations and veins within Oko Mts. The primary deposit is most probably of a quartz-gold and/or quartz-gold-pyrite type. I observed large quartz veins in purple schists between Oko Mts. and Oko river. The alluvial material which forms the prospect was contributed by Cuyuni, Oko and Ekribisi rivers. It is trapped in a natural riffle between two belts of harder rocks (doleritic dikes) through which Cuyuni river had to break in falls and rapids. Flat topped hills indicate an extensive erosion cycle in the area and my experience suggests a strong possibility of one or two "false bottoms" with gold rich gravel below them. In Potaro River gold grade, just below the first hard clay ("false bottom"), was 87 times higher than the top gravel grade!

Aerial photos show, within the prospect, a system of paleochannels related to Cuyuni River's lateral movements.

Gold grade:

The overall (over a total volume of material) gold grade is between 0.85 and 4.5 g/m³. Paleochannel has a higher gold grade than active river channel where constant addition of sterile alluvium dilutes overall gold grades.
A bulk sampling pit, within a paleochannel below Oko river mouth, produced 261 ozs. from ~7,000 m3 of sand/gravel. (1.16 g/m³)

The active river channel was dredged during late 70's and early 80's with 6 inch jet pumps. The average production, for a 15 h. work-day, was between 10 and 15 ozs. per day. Later, 8 inch gravel pump dredges reworked tailings, and in the same length work-day produced 4 to 6 ozs. per day. At the end of 1997, few dredges were reworking old tailings for a 1.5 to 2 ozs. per day production.