Metals company Pensana on September 14 confirmed that the Sulima West laterite target at its Coola exploration project, in Angola, contains three main types of rare-earth minerals.
This was confirmed as the company reported on the mineralogical characterisation studies – undertaken by testing services provider SGS South Africa – of samples collected at the Sulima West and Coola carbonatite last year.
This comes in addition to the announcement on August 29, in which the company reported high-grade total rare earth oxide soil sampling results at Sulima West, as well as encouraging results from other targets on the Coola exploration licence area.
“We are encouraged that the initial mineralogical study has confirmed the processing potential of the rare earth host minerals for both the Sulima West laterite and the Coola carbonatite,” enthuses Pensana exploration manager Grant Hayward.
“The opportunity for upgrading the ore at the current location using physical separation techniques will be further assessed with the testing of larger samples which are in the process of being collected.
“We obviously see both Sulima West and Coola carbonatite as having the potential for upgrading the ore at its current location and thereby providing a high-grade near-term feedstock 40 km from Longonjo.”
Pensana confirms that the Sulima West laterite contains three main types of rare earth minerals namely bastnaesite, monazite and florencite. The important neodymium and praseodymium (NdPr) mineralogy occurs mainly in the monazite, while the bastnaesite hosts the cerium and the lanthanum occurs in the florencite.
The minerals have been also partially liberated from the weathered host rock. The minerals should be amenable to some degree of simple upgrading at the current location, while the moderate exposure noted should be sufficient for successful process route leaching, with the bastnaesite and the monazite showing the highest recovery potential.
For the Sulima West apatite-maghemite target, Pensana states that the majority of the rare-earth minerals present in the apatite-maghemite sample occur in the apatite.
“The apatite is relatively coarse-grained and is well liberated and exposed. Whilst apatite is not a typically recovered rare-earth mineral, this sample is well liberated and exposed and as such would be amenable to potential recovery and may constitute a significant phosphate resource,” explains Pensana.
The Coola carbonite, meanwhile, contains a significant amount of bastnaesite, which is host to more than 90% of the light rare earths found in this sample.
As the bastnaesite is moderately liberated and exposed, there is potential for recovery using the physical separation at the current location prior to processing at Longonjo.