JSE- and TSX-listed Witwatersrand Consolidated Gold Resources’ (Wits Gold’s) De Bron-Merriespruit (DBM) gold project is planned to become the next shallow gold mine to come into production in South Africa.

The project is a combination of the De Bron project and the Merriespruit south area acquisition, which is expected to be complete in October.

Previous studies indicate that the project, to be located near Virginia, in the southern part of the Free State goldfield, has a relatively shallow gold reef that starts at a depth of 500 m, with a cutoff grade of 6 g/t.

The results of the scoping study were released in June and the company is currently in the process of moving from a scoping study into the prefeasbility study. Additional drilling has started.

“The effective results of the scoping study are encouraging for the company and we plan to start with engineer involvement by the end of this month,” says Wits Gold CEO Dr Marc Watchorn.

From the scoping study at the DBM project, it was established that the Beatrix, Kalkoenkrans, B and Leader reefs occur at depths of between 500 m and 1 250 m below the surface.

The scoping study was undertaken independently by mining and engineering consultant Turgis Consulting with the participation of consulting services company Snowden and was completed under the guidelines of the Canadian National Instrument 43-101.

The study was based only on the indi- cated resources of gold and uranium, but also considered the potential contribution that could be made by the conversion from inferred resources.

“The fact that we have converted from inferred to indicated resources has resulted in Wits Gold having a positive outlook on a project that was initially only fairly marginal,” says Watchorn.

Meanwhile, a preliminary assessment to investigate the economics of mining the indicated resource of uranium that occurs within the Leader reef has started, as the company was not clear on the inclusion of the uranium, and the matter needs to be reviewed again.

As there is a close vertical association between the Beatrix and Kalkoenkrans reefs, it is assumed that the higher- grade Kalkoenkrans reef will be selec- tively mined rather than the overlying Beatrix reef. The only exception will occur in areas where the two conglomerates are directly superimposed, so that they can be exploited in a single mining cut.

Based on an assessment of the rock mechanics, it is concluded that the Kalkoenkrans, B and Leader reefs will be exploited as discrete, separate orebodies. All these reefs dip consistently at between 12º and 18º towards the north-west and have been dissected into a number of coherent structural domains by syn-Ventersdorp faults.

A combination of the gold grade distribution and a three-dimensional wireframe model provided the basis for a number of different mine designs for the DBM project.

At this preliminary stage, financial modelling indicates that optimum returns are likely to be achieved by establishing a shallow underground mine design, comprising a 700 m vertical shaft served by a 12º conveyor decline.

The scoping study anticipates a pre- liminary production model for the DBM project, based on similar mining opera- tions in South Africa, using footwall haulages, crosscuts to the reef at 150 m intervals and conventional breast stoping by hand-held rock drills and scraper winches.

Ore generated in the stopes will pass through box holes into the crosscuts, from where it will be loaded by load-haul dumpers onto trucks for transfer to the decline ore-pass system. The ore will be transported to surface by a conveyor, feeding a purpose-built carbon-in-leach plant for crushing, milling and gold recovery.

The complementary vertical shaft will be used for workers and materials, while additional ventilation will be pro- vided by raised boreholes, drilled from the surface.