Thursday June 20th
Before the start of the technical sessions I had the great pleasure of presenting Randall Zahn, of
|David Wiseman and MEI's Amanda|
David Bowman, of Bear Rock Solutions, Australia described how, in association with Newcrest Mining Ltd, a robust scientific plan has been devised which examines the fundamental nature of waste rejection, the possibilities for exploitation and how it could be employed across their various operating sites and in future operations. The total project examines a range of waste rejection techniques capable of deployment at coarser size ranges and these include systems based on, size, gravity, physical and chemical properties. The results of this study show that some process streams offer significant potential for waste rejection, but in most cases there is no “one pass” waste rejection option. Rather the rejection process becomes a series of liberate-separate cycles. At each stage the altered physical characteristics of the material open different possibilities for rejection techniques.
|Martin Brandaeur and John Clout prepare for their presentations|
The average grades of many mineral ores are in long term decline while the demand for minerals and metals continues to increase. The overall effect is to increase the consumption of energy per tonne of metal produced. For many ores, most energy is consumed in communition, and for many low grade ores much of the communition energy is expended on barren rock.
One way to moderate this dilemma is to sort ore at coarse sizes to reject very low grade or barren gangue. Rejecting waste at coarse sizes reduces the energy required for communition and per unit of metal produced. Such dry ore beneficiation is an objective in many mines nowadays. Water withdrawal and disposal and all related environmental aspects became key issues, even more in arid areas. Sensor based sorting technology using X-Ray-Transmission (XRT) has proven its ability in recent years in industrial scale applications. High efficiencies and recovery rates can be achieved using the latest technologies. Powerful computers and increasingly sensitive X-ray scintillation counters have allowed the development of high-performance units. The machines have reached a status of rigid and reliable field stability and can be operated at grain sizes of 8 mm up to 70 mm, depending on the individual ore.
|Jens-Michael Bergmann with |
Industrial Minerals' Laura Syrett
Rob Morrison of the
Three papers on hydrocyclones started the afternoon session. Johann Dueck of the Friedrich-Alexander-Universitat,
Positron Emission Particle Tracking (PEPT) was developed at
Maryam Ghodrat, of the
|Chris Rehmann with Suresh Srinivasan|
Talking of water, the weather has been atrocious today, but despite the conditions, around 20 hardy souls braved the elements for the evening coastal path walk. The 17th century Chain Locker pub provided a warm and dry destination, and good Cornish ale in the company of the Cornish Mining Sundowner whose monthly meeting happily coincided with the walk.
|Drying out at the Chain Locker|
Friday June 21st
This morning’s papers were an eclectic mix, starting with a presentation from Daniel Amariei of COREM,
Gravity concentration modelling was also the subject of a paper by Jean-Sebastien Kroll-Rabotin, of the
Eduardo Crespo, of Daytal Resources,
Rare earth elements are becoming increasingly important for a variety of uses (see posting of 1st February). Rare earth (RE) mineral deposits are typically processed using several different unit operations including gravity, magnetic, electrostatic and flotation separation. Two of the most important beneficiation techniques for RE minerals are gravity and magnetic separation. Many RE minerals are found alongside low specific gravity gangue minerals thereby permitting the use of gravity separations to concentrate the heavy value RE minerals. Magnetic separation is used primarily to remove ferromagnetic gangue minerals as well as to separate individual paramagnetic rare earth minerals. Adam Jordens, of
The internal workings of wet Low Intensity Magnetic Separators are poorly understood, and Jan Stener, of Lulea University of Technology, Sweden, showed how ultrasonic velocity profiling could be used to enhance our understanding.
Rob Morrison of the
|Dave Wiseman with Rob Morrison and Hugh Rice|
In the final presentation, Chris Pickles, of Queen’s
CD from MEI. Final papers will be peer-reviewed and published in a special Physical Separation issue of Minerals Engineering.
During my 22 years at Camborne School of Mines (CSM), I must have made the journey to Camborne and back many thousands of times, but it is always fascinating to see the gradual change in the landscape, from
We were privileged to have an exclusive tour of the award winning King Edward Mine (KEM) Museum, once owned by CSM, and where I had my first office! The mill at KEM simulates the flowsheet of an early 20th century tin dressing plant, with now obsolete devices such as Frue vanners, hand jigs, round frames, buddles and rag frames. The Californian stamps were also run for a short period, to give us an impression of the cacophony of sound which must have assaulted the ears in those far-off days when hundreds of mines were operating in this area. On behalf of the group I must thank Tony Clarke, who I worked with all those years at CSM, Frank Kneebone and conference delegate Nigel MacDonald for hosting us, and for their deep knowledge of, and enthusiasm for, Cornish mining.
|Overlooking Marriott's Shaft, Wheal South Frances|
|West Basset with the stamps engine house in the background|