Design holds promise for heart surgery

UCT researchers have turned to medical technology to study the inner workings of one of the mining industry's most common mineral processing devices, resulting in an application that could hold major significance in the field of heart surgery.

The resultant paper has been awarded the 2006 Peterson Award for the Best Applications Paper published over a two-year period in the Journal of Experimental Mechanics.

The paper (vol 44, no 5, pp 593-607) was co-authored by Indresan Govender, Andrew McBride and Dr Malcolm Powell, all of the Mineral Processing Research Unit. The Society of Experimental Mechanics, based in the US, made the award. The trio has been invited to receive the award at their next congress.

A quote from the letter reads: "The selection of your paper is a well-deserved public recognition by your professional peers of the quality and thoroughness of the approach you took to this highly-challenging problem."

More traditionally used for scanning heart-valve motion in medical patients, a biplanar angioscope is being used to create a three-dimensional image of a tumbling mill as a way to validate results from an increasingly popular branch of applied research, known as Discrete Element Modelling (DEM).

According to Powell, DEM is essentially a way of describing what is going on inside the mill, based on Newton's laws of force and motion. It is used in designing mill components, such as liners, and to predict power draw in mineral processing milling equipment.

"As the use of energy is potentially a large cost to a milling operation, we believe that DEM holds the key to reducing costs through a better understanding of what is happening inside the mill."

To get an accurate validation of a DEM description, PhD student Govender used X-rays taken with the angioscope to create a three-dimensional image of the scaled-down Perspex tumbling mill that he has built.

"Until now, no-one has used this very expensive and highly sophisticated piece of medical equipment, found almost exclusively in hospitals, to work on a mineral processing problem," Powell explained.

"An angioscope is a multimillion rand piece of equipment, so we take our little mill rig, which is designed to be portable, and do our test work in an operating theatre at Tygerberg."

The DEM/angioscope approach has the potential to test other mineral processing equipment, such as cyclones, and has implications for open-heart surgery in the future, if their research proves successful.

"How we as mineral processors could help the medical profession is by creating a three-dimensional image of a catheter going into the heart," Powell explained. "Surgeons have to work within centimetres, but we can locate our mineral particles within 0.2mm."