Metallurgy
Northam’s original mineral processing operations were constructed at a capital cost of ZAR1 350m, designed in two single stream processes to achieve annual ore throughput of 2.4Mt. The first PGMs were produced in 1993.
With the UG2 expansion project in 2000, Northam started mining the UG2 reef and built and commissioned the R80 million UG2 concentrator plant. With its relatively few reef disturbances on the UG2 reef horizon, mining conditions are easier. As a result the UG2 reef is now extensively mined, with a drive to maximize production and processing in order to take advantage of the buoyant markets for PGMs.
Merensky and UG2 ore is processed separately in the two plants, which are designed to treat sulphide ores, with the concentrate from both being blended in slurry form in the feed tank prior to filtration and drying at the smelter from which granulated converter matte is fed to the base metals removal plant (BMR).
Technical overview - Enlarge metallurgical process diagram
| Description | Date of commissioning | Capacity | Current volume throughput | Function |
|---|---|---|---|---|
| Merensky concentrator | 1993 | 150 000 tpm | 130 000 tpm | Crushing, milling, flotation |
| UG2 concentrator | 2000 | 75 000 tpm | 75 000 tpm | Crushing, milling, flotation |
| Smelter | 1993 (scheduled rebuild in 2003) | 15MW | 9MW | Drying, smelting, converting |
| Base metals removal plant | 1993 | 360 tmp matte |
330-340 tmp | Atmospheric and pressure leach |
