The Mustardo occurrence is located at an elevation of approximately 1040 metres on a southwest-facing slope, approximately 4.6 kilometres west of the west end of Hatdudatehl Lake.

The area is underlain by andesite tuffs and minor flows of the Upper Triassic Inzana Lake Formation (Takla Group), which have been intruded by small monzonite plutons. Tuffaceous units range from thinly bedded fine muddy tuffs through massive fine-grained lithic tuffs to cherty lapilli tuffs.

Locally, an andesite tuff, later described as a silicified volcanic flow or mudstone, and biotite-feldspar monzonite porphyry host quartz stockworks with disseminated and fracture filling pyrite, molybdenite and chalcopyrite with malachite staining. Disseminated pyrite and pyrrhotite are also reported in the Takla Group volcanics and sediments, whereas finely disseminated magnetite is reported in the monzonite intrusive.

In 2008, rock samples (78289 and 78290) from the same outcrop yielded values up to 0.071 per cent molybdenum, 0.946 per cent copper, 96.8 grams per tonne silver and 0.798 gram per tonne gold (Assessment Report 30925).

In 2009, a rock sample (Inza-BB-1) from the same outcrop as the previous samples yielded 0.005 per cent molybdenum, 0.245 per cent copper, 58.4 grams per tonne silver and 0.343 gram per tonne gold (Assessment Report 31192).

In 2011, drilling on the occurrence area intercepted hornblende felspar porphyry hosting disseminated and fracture-controlled pyrite-molybdenite±pyrrhotite±chalcopyrite mineralization and narrow sulphide with quartz±calcite±sphalerite veins. Drilling intercepts included 0.112 gram per tonne gold and 0.101 per cent molybdenum over two separate 1.0-metre intervals in hole INZA-11-01; 0.021 and 0.015 per cent molybdenite over 9.1 and 36.3 metres, respectively, in hole INZA-11-02; 0.287 gram per tonne gold over 1.1 metres of fault zone material in hole INZA-11-03; 0.293 gram per tonne gold and 0.121 per cent copper over 1.5 metres, along with two other separate 1.5 metre intervals grading 0.152 and 0.181 gram per tonne gold, in hole INZA-11-04; 2.250 grams per tonne gold over 1.5 metres in hole INZA-11-05 and 0.464 gram per tonne gold over 4.5 metres and 0.129 per cent copper over 1.1 metres in hole INZA-11-06 (Assessment Report 32942).

In 2018, a rock sample (TZR-22) of quartz biotite intrusive with arsenopyrite filled fractures, located approximately 300 metres to the southeast of the main Mustardo zone, assayed 5.8 grams per tonne gold, whereas another rock sample (TZR-29) from a quartz-pyrite-chalcopyrite vein, located approximately 550 metres to the northeast of the main Mustardo zone, yielded 4.34 grams per tonne gold, greater than 100 grams per tonne silver and greater than 1.00 per cent copper (Assessment Report 37964). Another sample (TZR-31) of quartz breccia with disseminated pyrite and molybdenite, taken a short distance east of the previous sample, yielded 0.156 gram per tonne gold and 0.116 per cent molybdenum (Assessment Report 37964).

Work History

The area was first staked as the Tez claims in 1989 by Rio Algom, who is reported to have conducted an airborne magnetic survey, though this was not filed for assessment. In 1990, Rio Algom explored by mapping and a 2191-sample grid soil geochemical survey.

The SAS 1 claim was prospected in 1995 by Don Johnson who collected 28 rock and 15 soil samples. In 1996, Johnson collected 17 rock samples and in 1997 he collected a further 24 soil and 11 rock samples (PAP RPT 1996-33; 1997-10).

In 2005, Uwe Schmidt prospected his Carmen claims, which were staked to cover the lapsed Tez claims of Rio Algom and some of the lapsed SAS claims of Johnson. A total of 11 rock samples, 1 deep till sample and 1 soil sample were collected in 2005.

In 2008, Strongbow Exploration Inc. completed a program of rock, silt and soil sampling on the area as the Inza property. The following year, a program of rock sampling, geological mapping and 22.0 line-kilometres of induced polarization and magnetic surveys were completed on the property.

In 2011, Xstrata Canada Corp. completed a program of prospecting, geological mapping, soil sampling, an induced polarization survey and nine diamond drill holes, totalling 1946.3 metres, on two magnetic anomalies on the Inza property. Six of these drillholes were located on the hill side a short distance east of the Mustardo occurrence.

In 2018, John B. Kreft completed a program of rock and soil sampling on the area as the Tez property.