Set in Jwana Game Park surrounded by 1700 animals, the unassuming Jwaneng Mine, part of the Debswana Mining operations in Botswana is reportedly the richest diamond mine in the world by value. As part of the Jwaneng Resources Extension Project (JREP) under the department of Mineral Resources Management (MRM), a new combination disk mill from German company Fritsch has been commissioned by Labotec to provide a powerful combination for crushing samples to study kimberlitic ore resources at depth as well as update the resource model that the Debswana will mine at Jwaneng in the future.
The new Fritsch mill and jaw crusher is located at the geology core sheds. During the JREP Phase 2 core drilling project, PIMA (Portable Infrared Mineral Analyser) samples from the kimberlitic core are collected at five meter intervals. Previously the crushing for characterising different kimberlitic facies was carried out using pestle and mortar, which was time consuming and noisy and ergonomically strenuous for the team. Now, fine crushing can be achieved in a single step in seconds. The team cuts 10mm thick discs of core and crushes them into fine sample for analytical purposes to assist in characterising the different kimberlitic facies.
According to Rathari Moalosi Field Officer, the Fritsch combination mill and crusher, “was a portable mini crusher that we could move around, and suited our needs. He added, “Labotec provides robust equipment; for example the old oven we use for drying samples is more than twenty years old but still works. If we have problems with equipment, Labotec technicians are there to help us”.
Some preferred features of the combination mill are the especially solid thick-walled housing made from recyclable grey cast iron, safety features and the fast, easy cleaning. The Fritsch Jaw Crusher P1 and Fritsch Disk Mill are mounted together onto a rack and connected to each other by a chute. Material of up to 3-5cm is automatically ground in a continuous operation down to fineness freely adjustable between 12mm and 0.1mm. This combination can also be used in pilot plant situations for fine grinding of up to 150kg per hour of hard-brittle and medium-hard solids in continuous operation.
Currently Jwaneng is mining to a depth of 350 meters, and is expected to reach 624 meters by 2017. Production varies according to the mining plan, but normally 10 to 15 million carats are mined annually.