The MFJ prospect occurs about 7.5 kilometres southeast of the village of Iskut, and 4.25 kilometres southeast of the North ROK developed prospect (104H 035). The prospect is 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 to 1996) headed by C. Ash of the British Columbia Geological Survey 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 Fieldworks 1994 to 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 (potassium-feldspar) and silicification of the host monzonite (East) and syenite (North) stocks grade outward to a propylitic alteration assemblage (chlorite, epidote, montmorillonite, and calcite) accompanied by 1 to 4 per cent pyrite. Potassic alteration, accompanied by intense brecciation, quartz veining and upwards of 10 per cent 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 mineralization. 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).

In 1990, sampling of trenches on the Main zone yielded values of up to 0.449 and 0.530 per cent copper with 0.377 and 0.617 gram per tonne gold over 114 and 36.0 metres from trenches no. 1 and 2a, respectively, while sampling of trenches on the South zone yielded up to 0.325 per cent copper and 0.206 gram per tonne gold over 27.0 metres in trench no. 13 (Peatfield, G.R. (2006-09-20): Technical Report on the ROK Copper-Gold Mineral Property). Drilling, performed at this time on the Main zone, yielded intercepts of up to 1.32 per cent copper and 1.540 grams per tonne gold over 38.37 metres in hole 90-R03 (Peatfield, G.R. (2006-09-20): Technical Report on the ROK Copper-Gold Mineral Property).

In 1991, drilling on the Main zone yielded intercepts of up to 0.312 per cent copper and 0.240 gram per tonne gold over 42.0 metres in hole RO-01-91, while drilling on the South zone yielded up to 0.180 per cent copper and 0.240 gram per tonne gold over 6.0 metres in hole RO-04-91 (Peatfield, G.R. (2006-09-20): Technical Report on the ROK Copper-Gold Mineral Property).

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 surveys (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.

In 2011, geochemistry surveys were performed by Lions Gate Metals Inc on the ROK-Coyote claims (owned by Firesteel Resources Inc.), in the vicinity of the MFJ (104H 001) and West (104H 002) mineral occurrences, in order to extend historic copper in soil anomalies (Assessment Report 33117). A total of 8 rock samples, 885 soil samples and 31 mobile metal ion soil samples were collected. Anomalous copper and gold values were returned from both the soil and mobile metal ion samples, beyond the historic anomalies. A 26.275 line-kilometre ground magnetic survey was performed concurrently with the geochemical surveys.

In 2013, OZ Exploration Pty Ltd carried out an exploration program on the ROK Coyote project area, under a Joint Venture agreement with Firesteel Resources Inc (Assessment Report 35259). OZ drilled 1740 metres in 3 three diamond-drill holes, conducted 26.5 line-kilometres of 3D offset line pole-dipole IP/resistivity surveying and 316-line kilometres of airborne magnetic and radiometric surveying. Eight MINFILE occurrences were covered by the airborne survey with four of these (MFJ, West, B18 and O.K) also occurring within the IP/Resistivity survey boundaries. The 8 MINFILE occurrences are: MFJ (104H 001), West (104H 002), South (104H 006), Hi (104H 014), Coyote 3 (104H 024), B18 (104H 032), Silver Standard (104H 045) and O.K. (104H 046). Drill hole DD13RK001 was located 170 metres north of the MINFILE occurrence plot for MFJ (104H 001). Drill hole DD13RK002 was located 800 metres west-northwest of the MINFILE occurrence plot for O.K. (104H 046). Drill hole DD13RK003 was located 390 metres west of the MINFILE occurrence plot for B18 (104H 032). A total of 3500 hectares of geological mapping was also completed. A number of chargeability and resistivity anomalies were discovered, some of which were tested during the 2013 drilling. See MINFILE occurrences MFJ (104H 001), O.K. (104H 046) and B18 (104H 032) for drill results.

Drill hole DD13RK001, located 170 metres north of the MINFILE plot for the MFJ (104H 001) prospect, was reported to have targeted the continuation of high-grade copper mineralization at depth below historic drill hole 90-R03. Drilling targeted a discrete magnetic anomaly and a large low magnetic signature. Although drill core revealed rare chalcopyrite associated with “late” epidote/carbonate clots, it was reported that drilling failed to intersect copper mineralization that would indicate a significant porphyry style body in the vicinity. The hole was completed at 751.9 depth.

In 2017, Colorado Resources entered into a purchase agreement, with Firesteel Resources Ltd. to acquire a 100 per cent interest in the ROK-Coyote copper gold property. The ROK-Coyote property occurs immediately south and east on trend of Colorado’s North ROK property and immediately north and west of Imperial Metals Red Chris property.

The MFJ prospect is one of seven anomalous areas with greater than 200 parts per million copper plus elevated gold in soils, determined from historic and 2017 soil sampling, that characterize a nine-kilometre-long favourable mineralized trend. The trend extends from the Mabon (North ROK) developed prospect, southeast to Ealue Lake (Colorado Resources News Releases November 21, 2017, January 18, 2018).

On Sept 16 of 2020, Colorado Resources announced that it had changed its name to “QuestEx Gold & Copper Ltd.” effective September 28, 2020.

See North ROK (104H 035) for related geological, historical, and bibliographic information.