The MFJ prospect lies within the Rok claim (previously known as the Rose of Klappan), approximately 7.5 kilometres southeast of the village of Iskut. The prospect is located in a broad, northwest trending valley in the highly dissected terrain of the Tanzilla Plateau. The property lies within the Stikine Terrane of the Intermontane Belt.
A 3-year mapping program (1994-96) headed by C. Ash of the British Columbia Geological Survey has led to an updated stratigraphic framework for parts of NTS mapsheets 104G/9 and 16 and 104H/12 and 13, including the area of this occurrence. This new interpretation is published in Fieldwork 1994-1996 and Open File 1997-3.
The Lower Jurassic Hazelton Group underlies the MFJ area and consists of andesitic volcanic breccias and conglomerates. These are described as grey-green and maroon, feldspar-hornblende porphyritic andesitic to dacitic debris flows and lahars; minor flows; with intervals of green and maroon epiclastic conglomerate and medium to coarse grained crystal lithic wacke with angular, red mudstone fragments. In this area, this unit is further defined as being epidote-chlorite-calcite altered.
These are intruded by porphyritic hornblende quartz monzonite of the Early Jurassic Edon and Rose plutons and related syenite stocks.
The MFJ prospect, which encompasses the East and North showings (Assessment Report 17316), is an alkaline copper-gold porphyry deposit with disseminated and fracture filling chalcopyrite, pyrite and magnetite in a quartz-vein stockwork. Intense potassic alteration (K-feldspar) and silification of the host monzonite (East) and syenite (North) stocks grade outward to a propylitic alteration assemblage (chlorite, epidote, montmorillinite and calcite) accompanied by 1 to 4 per cent pyrite. Potassic alteration, accompanied by intense brecciation, quartz veining and upwards of 10 percent sulphides including bornite and chalcocite (Assessment Report 17316), is noted enveloping monzonite dikes peripheral to the MFJ prospect. Mineralization at the MFJ prospect has been tested by several trenches and nine drillholes in 1982. The best drill intercept, from the East showing, was 1.07 per cent copper and 0.04 gram per tonne gold over 15 metres (Assessment Report 17316). Diamond drilling and surface sampling were reported to confirm the presence of porphyry copper minealization. A high-grade zone has been identified in 1990 drill core, assaying 4.25 per cent copper and 6.17 grams per tonne gold (Assessment Report 20689).
The area was first prospected in 1929 when an adit and several trenches revealed copper mineralization on the adjoining Klappan Rose property (presently the HI claims, 104H 014). The property was extensively explored by geological, geochemical and geophysical surveys from 1960 to 1988. In 1987, Taiga Consultants Ltd. staked the Rok claims for Manchester Resources ltd. and then carried out detailed mapping, geochemical surveys and a ground magnetometer survey (Assessment Report 17316). The property was under option to Consolidated Carina Resources Ltd. in 1990 and they commissioned Keewatin Engineering Inc. to carry out an exploration program. This work consisted of 373.3 metres of diamond drilling in three holes, a 2.5 kilometre induced polarization survey as well as further rock, soil and silt sampling suveys (Assessment Report 20689). Keewatin's commission was extended to 1991 at which time they completed five diamond-drill holes totalling 716 metres. They also conducted various geophysical (induced polarization and magnetics) and geochemical surveys (Assessment Report 21901). In 2005, a helicopter-borne geophysical survey was carried out on behalf of Firesteel Resources Inc. on the Rok property. The survey comprised a new tri-directional magnetic gradiometer system, and a gamma ray spectrometer system. The airborne survey was flown at 200 metre line spacings with a total survey coverage of 611.4 line kilometres.