Resources group Tengani Titanium Minerals (TTM) has engaged South African metallurgical experts to determine the most suitable method for the recovery of high-grade rutile at its titanium deposit in southern Malawi.
TTM, a consortiun of South African and Malawian investors, explains that the Tengani deposit constitutes two discrete titanium deposits of different types, grades and genesis, with the main deposit defined as “a higher-grade area”.
States the company: “Work recently completed by SGS in Johannesburg demonstrated that a rutile-ilmenite product could be recovered. Unfortunately, recoveries were lower than expected, largely because of the overlap of the physical properties of rutile and ilmenite, with some of the other minerals present (such as garnet). This causes these undesir- able minerals to report into the product streams, diluting them. Further cleaning is thus required, with associated further loss of product. Alternative mineral processing routes are currently being examined.
SGS also suggested that a liberation study should be undertaken to determine what percentage of the rutile and ilmen- ite are present as free grains.
“It may be that some of the grains present in the product streams are not fully liberated and are entraining other minerals. This is currently being investigated.”
Studies performed by South Africa’s Mintek on samples from the second deposit showed that the deposit contains rutile, ilmen- ite and apatite, with minor quantities of zircon.
“Unfortunately, the ilmenite and rutile are strongly intergrown and current laboratory work suggests that these may not be physically or mechanically separable. This deposit has been downgraded until further process work is completed,” says TTM.
Meanwhile, the company has announced that it has taken on board Brian Taylor, of Brusmet Metallurgical Consultants, who was previously project manager for the Corridor Sands project, in Mozambique, as a shareholder and director.
The existence of heavy minerals in the Tengani area has been investigated since the 1960s, when American pigment producer La Porte completed an extensive evaluation of the area. This work was followed up by a number of other companies as recently as 2002.
TTM completed a pitting programme and sent representative samples to metallurgical laboratories in South Africa for full mineralogical and metallurgical evaluation.
The Tengani heavy mineral sands deposit, estimated to contain several million tonnes of heavy minerals, will have a mine life well in excess of 20 years at an initial mining rate of 11-million tonnes a year during the first phase.