Mulwarrie Gold Project

Western Australia

The Mulwarrie Gold Project is located 150km north-west of Kalgoorlie in the Ularring District of the North Coolgardie Mineral Field. The project encompasses two contiguous tenements, M30/119 (68 Ha) and M30/145, which lie 10km north-west of the Davyhurst Mining centre.

Figure 3: Location, Mulwarrie project

The two tenements lie within a 10km wide greenstone belt which forms the north-west extension of the Coolgardie Line. The structurally dominant, north-trending Mt. Ida fault lies approximately 4km east of the Mulwarrie Mining Centre. Most of the lithologies within this greenstone belt are steeply dipping and well foliated along a NNW/SSE trend.

Figure 4: Mulwarrie tenements and simplified geology

Grades of metamorphism at Mulwarrie are generally higher than in the Kalgoorlie area with hornblende – biotite – plagioclase amphibolites common. Hornblende is diagnostic of the amphibolite facies and at Mulwarrie metamorphism has peaked at mid to upper amphibolite facies.

Gold mineralisation has been found in two distinct settings at Mulwarrie: –

  • In narrow shear zones with only minor or no quartz veining, with limited calcsilicate alteration haloes and with erratic but occasionally high gold values. The zones of mineralisation may be up to 2m wide but are generally less than 50cm. They are conformable to the stratigraphy and foliation; and
  • The second and most important type of gold mineralisation is associated with quite flat dipping often massive quartz reefs with strong diopside, biotite, epidote and carbonate alteration haloes. Pyrrhotite and pyrite development is also strong within and adjacent to the quartz reefs. Minor amounts of chalcopyrite, galena and sphalerite are also associated with gold mineralisation. Gold is found within quartz reefs, within biotite selvages to the quartz veins and also in the associated country rocks.