Diamond cleaning gets a robotic hand

Diavik Diamond Mines Inc.’ of Yellowknife, N.W.T., has a new automated robotic work-cell system at its Product Splitting Facility to handle the initial cleaning of diamonds from its mine, located 300 km to the northeast of the city at Lac de Gras, N.W.T. The system was designed according to Diavik’s specifications and built in Albuquerque, N.M., by Applied Thermal Systems, Inc. (ATSI), which develops processing equipment for the semiconductor industry.

In a 3.6-m x 3.6-m x 2.7-m addition (work-cell) constructed to house the automated caustic cleaning system, the custom-designed ATSI PFK200A robotic system handles the technical cleaning of the diamonds to remove any minerals adhering to the stones. A measured amount of chemical is placed into a steel crucible, which is conveyed to the work-cell where up to four heating stations raise the chemical to over 400C. The rough diamonds are placed into a wire mesh basket, which enters the work-cell via another conveyor to a pre-heater. When hot, the basket of diamonds is lowered into the melted chemical. After a predetermined period, the diamonds are removed, drained, cooled and conveyed out of the work-cell, ready for the next process. The spent chemical and mineral sludge is disposed of in a containment drum.

Although the work-cell has viewing windows, the automated system needs no people to run it. Product movements are handled by a Fanuc robotic arm and a pneumatic system, controlled by a single computer and two keypads set up outside the work-cell. A technician adjusts the time and movement variables depending on the size, shape and amount of diamonds in each basket.

In mid-September 2004, a specialized air-ride trailer delivered the system safely after a long ride from ATSI’s plant in New Mexico. By December the system had replaced the manual process, which had required workers to wear special personal protective equipment while they moved the hot crucibles. Not only safer and more efficient, the new system can also be safely operated by only one trained operator. An advanced software package also collects data for further analysis and product integrity. Each item and movement of the system is tracked for process times, temperature, type of product, results, operator use and many other factors.

Although this is ATSI’s first job with a major mining company, no doubt it will not be the last. According to partner Don Berg, ATSI is willing to look into automating any manual mining process. Besides Diavik’s caustic cleaning system, ATSI has already developed an advanced, automated acid bath system (PFK300) to handle the acidizing stage in the diamond cleaning process. In this system, a series of acid and water baths remove residue on the stones after initial processing. This equipment can work in conjunction with the PFK200A system or alone.

The features of these two systems can be viewed at: www.atsi-usa.com/products/diamonds.