The Sparky occurrence is located on a small hill or knob approximately 21.5 kilometres east-southeast of Mount Milligan.
The area is mapped as Carboniferous and Permian Slide Mountain Group consisting of greenstone, argillite, limestone, slate and quartzite. The prospect consists of two separate areas (knobs), 1200 metres apart, underlain by limestone.
Sparky's knob is underlain by limestone, dolostone, sandstone, quartzite and argillite. The massive, buff and grey weathering, medium to dark grey limestone outcrops from the 1060 metre elevation level to the peak at 1170 metres elevation. Strikes vary from east-west in the limestone to north-south in the underlying sediments.
The easternmost knob, called the 1242 Knob, is underlain by massive, medium grey weathering, buff to dark grey limestone which strikes 160 degrees and dips 53 degrees to the northeast. The limestone is confined to the top 40 to 80 metres of the knob.
The limestone was tested for total sulphur, maximum potential acidity, neutralization potential, paste pH, specific gravity and rock-forming oxides. The maximum per cent sulphur was 0.023 per cent with all other samples being between 0.002 per cent and less than 0.001 per cent. The acid generating potential for the samples taken was zero and the neutralizing potential was calculated as being from 918 to 971 tons CaCO3 equivalent per thousand tons of material. Paste pH varied from 8.1 to 8.8, and the one sample checked gave a specific gravity of 2.70.
Volume calculations were made using a computer program which estimated the topographic surface of the deposit based on elevation contours; the base of the deposit was estimated from the lowest outcropping. The Sparky's Knob deposit was estimated to contain 861,159 tonnes of limestone and the 1242 Knob, 819,445 tonnes (Assessment Report 20230).
Work History
In 1990, Continental Gold Corp conducted outcrop mapping, sampling, major oxide analyses, and rough volume calculation of limestone in See 15, 16 and 19 claims. Whole rock analyses of 9 samples was consistent with results expected for visually pure limestone. Clark concluded that limestone from Sparky’s and 1242 knobs have excellent neutralizing properties. Also in 1990, a 609.2 line-kilometre airborne magnetic and electromagnetic survey was completed on the See claims.
A preliminary investigation of limestone in Klein and See16 claims was carried out in 2005 by Placer Dome Limited as part of the Mount Milligan project (093N 194). The Klein knob is about 500 metres east of the 1242 Knob and was examined in 2005 by Placer Dome along with the Sparky and 1242 Knob. Sixteen rock chip samples were collected and submitted for whole rock XRF analyses. All samples were chipped from at least 4 centimetres beneath the weathering surface. Each sample was collected over approximately 10 metres inferred strike length, and 4 m inferred dip section. Five thin sections made for petrographic descriptions. Major oxide whole rock analyses of limestone samples indicate generally good purity and good potential for use in acid neutralization and hydrometallurgical applications. Silica content in most outcrops is below 1%, with the exception of Klein knob, where SiO2 varies from less than 1% to 3.35%. Dolomite content ranges up to 10% in Sparky and lower Klein knobs, but is low in all other outcrops.
