Post by
diabase1 on Jan 11, 2023 8:56am
Ireland2
On May 10, 2001, Northern Shield Resources "contracted to drill a single diamond drill hole FH-01 to test a potential kimberlite target on the north side of a small lake" (topographic depression) in Ireland Township (Assessment File 42H11SE2002/42H11SE2002). The hole was located at UTM 487209 5485091, just inside the south central boundary of the large magnetic feature in RTM's property, and just west of the major north south fault. "The first 30 meters intersected a relatively homogenous, buff colour clay which contains very little sand or pebbles and is interpreted to be Cochrane Till. Much of the remainder of the hole consisted of glacial till containing varying amounts of clay, sand, pebbles and boulders. At 71 meters down-hole a layer of unconsolidated sand and/or gravel was encountered which resulted in a complete loss of water return. The hole had to be abandoned with 184 feet of casing remaining stuck in the hole. Bedrock was not intersected". They were probably drilling into a graben, where the overburden would be much thicker. I believe that this diamond drill hole was the only one attempted by them on the Ireland Twp property.
Referring to the Ontario Geological Survey (OGS) Map M2590, it will be noted that the large magnetic anomaly (4 km long x 3 km wide) is located in a relatively quiet magnetic area with only a couple of NS diabase dykes, the closest being 2 km to the east. Does this mean an area of less brittle rocks, little extensional movement of land mass, or uplift, resulting in the absence of diabase dykes? There are also a few weaker NE/SW diabase dykes, which are located some distance from the Ireland Complex.
Referring to OGS Map 82 832, Ternary Radioelement Image, there is a very crude outline of a circular anomaly. However, I wouldn't put too much into this potential feature, because of the overlying glacial tills and clay and the widely spaced flight lines of the airborne survey. There are no outcrops of the underlying Precambrian basement in this area, as it is mostly covered with flat lying wet land.
In 2002, Northern Shield Resources completed a high resolution airborne magnetic survey over their Faint Hope property. As I'm not able to locate this survey report, I suspect that they did not file it for assessment credits. However, as a result of this survey, they carried out a ground magnetic survey in 2003 (Assessment File 42H11SE2003/42H11SE2003), on one of the smaller, positive magnetic anomalies within the large Ireland Twp magnetic feature. A kidney shaped anomaly was intercepted. This anomaly was located just inside the northwestern edge of the large magnetic feature. To my knowledge, it was never drilled.
Later, an attempt was made to collect a deep overburden sample from the fringes of this ground magnetic anomaly with a Pionjar drill. A single hole located at (UTM 487543E 5486348N, NAD 27 Zone 17) was drilled to a depth of 12 meters. A sample was sent for analysis, but returned with no kimberlite indicator minerals. Eight other holes were drilled (FH1-FH8) in other parts of the property. "Only 4 gold grains were reported from the 8 samples submitted for processing" and these were reshaped grains. "Although other heavy minerals were not rigorously picked, considerable pyrite (some still attached to quartz) and minor arsenopyrite, chalcopyrite and pyrrhotite was noted". The latter minerals are interesting!!
In 2007, Lake Shore Gold carried out a large airborne magnetic and VLF EM survey (MNDM Assessment File 20000002703/20004200) that extended from the Quebec border to as far west as the Little Abitibi River area. They were hoping to find the westerly extension of the Casa Berardi Fault. A portion of this survey covered all of RTM's Ireland Complex property. Several maps of magnetics and VLF were produced.