The Endeavor zinc-lead-silver mine is located 43km NNW of Cobar. The mine contains two styles of mineralisation: above about 900m depth an irregular sub-vertical sheet is hosted by a turbidite sequence and broadly coincides with an anticline axial plane; at the bottom of this sheet mineralisation bifurcates into grossly concordant zones.

The Endeavor mineralisation is contained within the Cobar Basin, which is in turn part of the Lachlan Fold Belt. Basement rocks include Ordovician sediments and Silurian granitic rocks. The basin contains mainly siliciclastic sediments with minor volcanic rocks and carbonates. Sedimentation continued from the Late Silurian until the Early Devonian. Polymetallic mineralisation within the Cobar Basin is thought to have coincided with a period of basin compression and folding (Lawrie and Hinman 1998). The mineralisation is largely discordant and vein or replacement in form. It is associated with silicic, carbonate and chlorite alteration. Most of the major known mineral deposits, including Endeavor, CSA, Peak and Hera are located along a linear structural corridor at least 200km in length.

High-grade massive sulphide mineralisation at Endeavor is enveloped by sulphide stringers, which are in turn enveloped by siderite alteration. The halo of siderite alteration extends for several tens of metres away from sulphide mineralisation and consists of 1 to 2mm diameter clots that preferentially replace sandy beds. Chloritic alteration also occurs.

Above about 900m depth the sulphide stringers form a large continuous lens or sheet which lies in an anticline axial plane. This lens ranges in thickness from 15 to 120m, extends from the surface to 900m at the S end of the mine, and has a strike length of at least 800m. At about 900m depth the mineralisation bifurcates into grossly concordant zones that dip down both the anticline limbs.

Stringers of sulphide generally sub-parallel slaty cleavage in the axial plane zone. The stringers are 5mm to 2m thick and mainly consist of pyrite, sphalerite, galena and chalcopyrite. Siliceous alteration sometimes accompanies the sulphide stringers, particularly in the upper parts of the mine. Similar stringers parallel to cleavage also occur in the concordant zones. However, in addition pyrite and base metal sulphides form conformable sulphide blebs that generally replace sandstone/siltstone beds and laminae. These blebs are preferentially distributed close to the cleavage-parallel stringers.

The composition of mineralisation changes vertically and laterally in the mine area. Within the axial plane zone, silver is concentrated in the upper and lateral sections of the high-grade massive lens, probably mainly within sulphosalt minerals. Grades of 300 to 1000 g/t are found compared with an average mine grade of about 70 g/t. Copper is concentrated at the base of the massive axial plane lenses within the centre of the pipe-like thickenings. Grades of over 4 percent are attained compared with an average mine grade of 0.2 percent. Lead and zinc are highest grade within the pyrrhotite cores of massive lenses.

The leases form a contiguous block of 10,121 acres in size and expire between 2019 and 2027. The mine employs bulk mining methods.

The mine utilizes a conventional flotation mill to produce a concentrate that is sold to a third-party smelter. Power to the mine and processing facilities is provided by the grid servicing the local communities.