The Ysoo occurrence is located about 46 kilometres southeast of the town of Fernie, just south of Twentynine Mile Creek.
The Ysoo mineral occurrence area is underlain by a thrust-faulted sedimentary panel of Mesoproterozoic Purcell Supergroup strata thrust northeastward onto a Mississippian panel of dolomitic carbonate rocks belonging to the Rundle Group. A Cretaceous syenitic to monzonitic stock intrudes the dolomitic panel a few hundred metres to the north of the Ysoo mineralized area.
On the Howell property at the Ysoo occurrence, a third (of four) forms of mineralization occurs as base metal (precious metal enriched) replacement in limestone, dolomite, and limy sediments in proximity to intrusive units. This style of mineralization has recently been referred to as CRD (carbonate replacement deposit) mineralization.
The Ysoo grid area was previously referred to as the southern portion of the Howe grid, which was placed prior to the Placer/Cominco joint venture. Soil sampling outlined a 1550-metre by 50- to 450-metre gold geochemical anomaly that was largely coincident with a zinc anomaly. From 1998-2000, Eastfield Resources Ltd. staked the 18-unit Ysoo 1 claim and optioned the Howell 1-5 claims from Placer Ltd and Cominco Ltd. In 1999, Eastfield carried out exploration on gold targets on the A and E grids (Assessment Report 26141, 26371). Work on the Ysoo 1 claim in 1999 (Assessment Report 26141) consisted of 17 rock samples in the vicinity of Placer Dome's 1988-1989 HRC-2 drill hole (Assessment Report 18629).
The southeastern grid was established in 2008 to fill in an area to the north of manto-style zinc, lead, silver mineralization identified in reverse circulation drilling completed by Placer Dome in 1988 where drillhole HRC-2 intersected 7.5 metres (at the bottom of the hole) grading 2.4 per cent zinc, 0.40 per cent lead, and 15.3 grams per tonne silver (Assessment Report 18629 and 30526 (Table 3)).
In 1999, visible mineralization was reported by Eastfield Resources to consist of copper carbonates, and sulphides, including malachite, azurite, galena, and pyrite. The copper carbonate sample (10987) was hosted in limestone of the uppermost Cambrian Elko formation. It is in association with one-to-two-centimetre irregular masses of dark purple fluorite, botryoidal hematite, and dendritic manganese. Mineralization had an irregular distribution as reflected in the original channel sample (10985), which produced only weakly anomalous copper values. Zinc and lead were moderately anomalous in sample 10987. Two samples taken within ninety metres of this location by Fox Geological Ltd. (1987) yielded 4 per cent zinc and 10 per cent (>99999 parts per million) zinc (Assessment Report 26141).
In 1999, the highest gold value obtained by Eastfield Resources was 1.75 grams per tonne (sample 10980), obtained from a moderate to strong argillic altered syenite sill. This sill lies on the periphery of an elevated soil contour plot which was drill tested by Placer Dome. The next highest value at 0.44 gram per tonne (sample 10989) was derived from sandstone with rhythmically layered quartz veinlets. Molybdenum, silver, and lead are elevated as expected in keeping with the intrusive influence.
Sample 10981 contains rare mm-scale coarse galena in the selvage of a four-centimeter quartz vein with upper anomalous molybdenum and silver values. The sample is derived from the arenaceous portion of the Cambrian Flathead formation yet is interpreted as localized late-stage mineralization related to intrusive activity. Historically, elevated molybdenum and silver in the region is associated with syenite, as reflected in sample 10980 at 7 parts per million and 13.7 grams per tonne, respectively. This association of molybdenum, silver, and lead hosted within quartz-bearing elastics was reported as consistent to the geochemistry profile on the Ysoo 1 claim.
See Eastern Outlier (082GSE078) for a detailed work history of the Howell property.
