The Bukit Besi’s mining areas straddle the contact between Palaeozoic sediments and granite, which is presumed to be of late Cretaceous age. Granite tongues have intruded the sediments up to 100 m beyond the main line of the irregular contact. Additionally, blocks of shale have been caught up and lie within the body of the granite.

Almost all the magnetite skarn mineralisation at Bukit Besi occurs as replacements in the sediments along or within 100 m of their contact with the granite. Magnetite and haematite replacement can also be seen within the granite. Here, fragments of altered sedimentary rock in this ore suggest that the ore has completely replaced bodies of shale engulfed by the granite. The orientation of the mineralisation is controlled by NE–SW, NW–SE and N–S controlling structures.

SRK defined the 3D magnetite estimation domains based on geochemical and magnetic susceptibility data, with boundaries being defined by step-changes in magnetic susceptibility, Fe%, S, SiO2% and TiO2%. The 3D geometry was observed to be relatively consistent and predictable over the extent of the drill coverage, with reasonable continuity between drill holes, although pinching and swelling of the veins was evident in both down dip and along strike directions.

West
At the West area, the six mineralised veins have an average strike length of 350 m, a combined width of 75 m and dip sub-vertically. The wireframes extend from the surface to 90 m depth.< ........

The operation utilises a conventional truck and shovel open pit mining method. Material is being mined on a bench height of 2.0 m, with drill and blast limited to a one bench depth in areas containing mill feed material. The average strip ratio is 4 to 1 waste to mill feed.

The current operations consist of two open pit mining areas which are located within mining lease ML7/2013, with conventional excavator and trucking of feed to a magnetite processing plant which is located within mining lease ML4/2013.

The processing flowsheet uses a 10-stage circuit which is summarised as follows:

1. Near-pit jaw crushing and coarse cobbling of the ore using dry magnetic separation.

2. Dual ball milling to produce a product P40 75 m that is pumped for screening.

3. Screening using a 1 mm aperture screens, with undersize passing to a Stage 1 magnetic separation and the oversize recycling to the ball mills.

4. Stage 1 magnetic separation, at a nominal 2,400 Gauss, to remove barren material to tailings and a magnetic fraction for regrind.

5. A regrind circuit, to grind the coarse magnetic material.

6. A cyclone cluster to direct fines material (P80 75 m) to flotation and the coarse material for further regrinding.

7 Stage 2 magnetic separation, at a nominal 2,400 Gauss, of the cyclone overflow material to remove a barren tailings stream.

8. Reverse flotation of the Stage 2 magnetic material where the sulphur-rich f ........