701
701 Mile Project (80% Laconia)
Gold and Base Metals The 701 Mile Project, covering 350km2 of Mesoproterozoic sediments and large mafic sills, is prospective for base metals, gold and manganese mineralisation. The project lies approximately 80km southeast of Newman within the northeastern portion of the Collier Basin (formerly termed Bangemall Basin) and is transected by a regionally significant structure called the Tangadee Lineament.
Overview of the 701 Mile Project geology and prospectivity
An overview of the 701 Mile Project geology and data indicates that the project is prospective for:
- copper-nickel-platinum group element sulphide mineralisation associated with the basal sections of large mafic sills;
- structurally controlled polymetallic lodes and veins associated with faults and the margins of mafic intrusions (although these may be of limited size potential); and
- gold developed in basement Archaean greenstones (albeit at depths below estimated to be below 400m) similar to the Frankopan Prospect, eight km’s north of the project area.
The project overlies rocks of the mid-Proterozoic Collier Basin, which represents the younger portions of the previously-termed Bangemall Basin. The local sedimentary group is correlated with the Manganese Group.
The northeast Collier Basin, including the Manganese Group, contains base metals (mainly copper, but some lead), and significant manganese mineralisation. Eight km’s to the north, gold mineralisation occurs in Pilbara Archaean greenstones below the Collier Basin sediments (Independence Group’s Frankopan gold prospect).
Lead-copper-barium mineralisation occurs at the Abra deposit, some 150km to the southeast, in the Edmund Basin sediments, adjacent to the Tangadee Lineament.
The distribution of mineralisation in the district is shown on the diagram below:
701 Mile Project regional geology and district mineral occurrences.
Geological overview
The project-scale aeromagnetic image shows a prominent northeasterly trending structural grain, with linear magnetic highs seemingly wrapping around mafic intrusions. The magnetic grain is interpreted to be a continuation of the Tangadee Lineament, which is a deep seated, long-lived structure which has controlled sedimentation during basin development.
Targets at 701 Mile Project
Base metals:
There is potential for structurally-controlled mineralisation adjacent to mafic intrusions, and also in differentiated basal portions of mafic sills. Mafic intrusives crop out in the central portions of EL52/1531, and have returned anomalous rare earth element values (0.23% combined REE) in a rock chip sample. Petrological examination indicated a monzogabbro for this outcrop. Elsewhere drilling has intersected mafic sills with gabbroic texture and pegmatitic zones. Elevated barium content (300-500ppm) is common, and barite veinlets have been noted. Of particular interest is the magnetic-high “rim” on the northern margin of a mafic body identified from drilling.
701 Mile Project total magnetic intensity image, drainage geochemistry and soil anomalies.
These sills may be far more extensive in the project than currently mapped, extending beneath the Quaternary cover.
Gold:
Potential exists for structurally controlled gold mineralisation and also for blind deposits in Archaean basement. The potential for structurally-controlled gold mineralisation at 701 Mile has been tentatively explored with BLEG surface sampling in the central portion of EL52/1531. This was designed to test the complex structural picture from aeromagnetic data. Pandell considers this sampling program to have been compromised somewhat by laboratory effects, and strike extensions remain untested. However, some modest spot-high gold values were returned, and further work is required.
Historical drainage geochemical data from other explorers returned two spot high gold values. One sample drains the previously-mentioned northeasterly trending magnetic high “rim” on the northern margin of a mafic body. The other anomalous sample is supported by four other elevated drainage responses, and is sourced from a structural intersection of a northeasterly lineament with a sinuous easterly trend. The source area is under cover and not yet followed up.
Gold has been discovered in Archaean mafic rocks at the Frankopan prospect, eight km to the north of EL52/1531. Mineralisation occurs within an alteration zone, at about 150-200m vertical depth, beneath Collier Basin sediments. Of note, is the observation that there is a very shallow dip for the base of the cover rocks. Occurrence of a similar style of deposit cannot be ruled out, but is not a primary target.