Technology and innovation

Diamond winning innovation to reduce breakage and increase recovered value.

The Letšeng mine has a unique diamond distribution with a significant portion of its revenue held in the +5mm fraction (greater than two carats). The quest to optimise the traditional diamond recovery process has not yet yielded the full potential to reduce diamond damage. Gem Diamonds continues to explore and evaluate new technologies to enhance diamond recovery and extract maximum value.

The opportunities for improved revenue through reducing diamond damage are (i) early identification of liberated or locked diamonds within kimberlite and (ii) non-mechanical means of liberating these diamonds. During 2017 progress was made in the development of key technologies that could be used to significantly reduce diamond damage, reduce costs and improve earnings.

DIAMOND DETECTION

Collaborations were established with various entities and institutions to advance the development of detection technology that can identify a diamond within kimberlite. The prospect of having technology that can detect diamonds within kimberlite at a rate of 1 000 tonnes per hour, makes this a very attractive opportunity for the Group. Among others, the Group evaluated positron emission tomography (PET) technology, which is a sensor-based sorting technology that can be applied to scan kimberlite to identify the diamondiferous rocks.

During the year, the Group embarked on a technical due diligence to assess the scientific merit, scalability and commercialisation options of this technology. The technical due diligence concluded that:

  • the physics of the PET technology applied in the minerals industry is sound and functional;
  • scalability challenges were identified that could be addressed in the development and engineering phase; and
  • value engineering is required to optimise the material handling and associated capital expenditure.

DIAMOND LIBERATION

Once a diamond has been identified within the kimberlite, the next step is to liberate this diamond without causing any damage. Gem Diamonds has developed a non-mechanical crushing system that utilises electrical power to break the kimberlite. During the year, a prototype was developed and has been successfully tested in Johannesburg, South Africa. Further testing at higher altitude is being carried out at the Letšeng mine.

The Group believes that the advancement of these and other technologies to detect and liberate diamonds within kimberlite will change the future processing paradigm, with a commensurate increase in the overall profitability. Plans have been approved to mobilise a test plant at Letšeng in 2019 to process tailings as part of the development of these technologies.

Process of liberating diamonds within kimberlite using innovative technology

a

Kimberlite rock to be scanned using PET technology

b

Scan results detecting diamond within kimberlite

c

Electrical power utilised to break kimberlite and liberate diamond

d

Rough 0.91 carat diamond exposed