Spring Stone, a joint venture between Canada’s Gold Canyon Resources and Japan Oil, Gas & Metals National Corporation (Jogmec), has announced the completion of a field exploration campaign that included exploratory drilling for rare earths at Chambe basin, in the Mulanje Mountain area of southern Malawi.

Spring Stone Malawi country manager Ryoko Kojima says, following completion of the field- work, the company is now conducting mineral resource calculation and an economic analysis of the project, including an infrastructure survey.

“Additional research and devel- opment work continue to seek the optimum rare earth element leeching process,” says Kojima.

Spring Stone, which embarked on the exploration campaign in 2011, contracted Japan’s Mitsui Mining Company as the contractor for exploratory drilling at the 400 km2 exclusive prospecting licence area.

Phase 1 drilling ran from September to October 2011 and involved the drilling of 24 holes. Phase 2 drilling was conducted from May to November 2012, and involved the drilling of 176 holes.

Kojima says the campaign discovered a superficial horizon of rare-earths-bearing kaolinite/halloysite clay ranging from 3 m to 26 m in thickness.

She explains that independent analysis of core from these holes indicates that the clay contains comparable levels of total rare earths enrichment to its Chinese counterparts, as well as similar heavy rare earths enrichment.

Kojima also says very low radio- activity is associated with the clays, which is potentially a positive metallurgical attribute.

In addition to drilling, the company undertook extensive baseline environmental work, including a study on how indigenous vegetation could be regenerated as part of future development of the site.

Meanwhile, Spring Stone has announced that it is cooperating with Malawi’s Ministry of Mining to secure other rare earths exploration opportunities in the country.

“Though our core business is to further develop the Mulanje project, we are evaluating further opportunities in other parts of Malawi, which is an under- exploited potential area,” says Kojima.

Malawi’s top geologist and Permanent Secretary at the Minis- try of Mining, Leonard Kalinda-kafe, describes the Mulanje Mountain deposit as an important and interesting discovery for Malawi because few such rare- earth deposits (with an ion-adsorp- tion clay type similar to China’s) have been found elsewhere.

“It is interesting because this is a rare deposit and I find it an important discovery for Malawi. Such types of deposits are cost effective in terms of rare-earth element recovery,” says Kalindekafe.

In a report on rare earths occurrence in Malawi, Kalinde-kafe indicates that most of the country’s rare-earth deposits are of the carbanatite type.

He reports that the country has great poten- tial to discover the minerals, mostly found in the Chilwa alkaline area, in the southern region.

The reports highlights the Kangankunde deposit, being pursued by Australia’s Lynas Corporation, and the Songwe Hill deposit, owned by Canadian-listed junior Mkango Resources, as some of the potential deposits in the area.