Wednesday, 15 October 2014

XXVII IMPC only 4 days away

MEI is a media partner for next week's International Mineral Processing Congress in Santiago, Chile.

I will be representing MEI and reporting daily with updates and photos both on the blog and on Twitter (@barrywills). You can also see what others are saying about the conference on Twitter at #IMPC2014.

If you are attending, and have news that you feel would be of interest to mineral processors worldwide, please get in touch with me either prior to, or at, the event. I would appreciate such news for my full report, which is scheduled for the blog on week beginning October 27th.

Around 1000 delegates are expected and there has been very strong corporate support, so I look forward to an interesting week.

 

Monday, 13 October 2014

What have models and measurements ever done for us?

There has been a lot of discussion recently, on this blog and on LinkedIn, of advanced models of mineral processing systems, how effective they are and how to convince operators of their efficacy.
Jan Cilliers
A keynote lecture to look forward to at next years Flotation '15 conference is "What have models and measurements ever done for us?" which will be presented by Prof. Jan Cilliers, who leads the  Rio Tinto Centre for Advanced Mineral Recovery at Imperial College UK. 
Prof. Cilliers will show how the history of flotation has key moments when there were significant advances in understanding.  It is notable that these moments are punctuated by advances in the theory or the experiment of flotation. These new techniques in modelling and measurement did not develop independently, but advances in one led directly to advances in the other. Subsequent application of these techniques resulted in improved industrial operation. It is clear that advances in theory and experiment take some time to move from the laboratory to the literature and on to the plant.  It is also clear that while some advances have made a significant impact on industrial flotation, there is still much potential for further application.

Stephen Gay
It is therefore timely that immediately prior to Flotation '15, Dr. Stephen Gay, an independent consultant who is committed to developing optimisation and simulation software and mathematical algorithms for mineral processing, will be running a 3-day Simulation Course. The course will cover all aspects from basic data accumulation and analysis to advanced software development. Delegates will gain insights into the metallurgical process via advanced mathematical techniques and be able to develop systems for high level decision making using modern techniques of computer simulation methodology.
Peter Amelunxen
In another keynote, Peter Amelunxen, of Aminpro, Chile will ask why, after more than 100 years of application of the flotation process—one of the most important technological advances in the history of extractive metallurgy—we still don’t have a standard test procedure for measuring the floatability of minerals in a given flotation system.  Most companies, labs or consulting engineers employ a different set equipment specifications, test procedures, scale-up methods.  Why? 
Flotation is a complex physicochemical mass transfer process, and it has been difficult to fully understand all of the underlying interactions.  While metallurgists can also be complex and difficult, it turns out that this is not the reason for the lack of a suitable standard; rather, the challenges are more practical by nature.  They include difficulties in quantifying, at the lab scale, the phenomena that occur in the plant; missing gaps in the phenomenological understanding of the flotation system; knowledge dissemination, particularly knowledge with respect to understanding and mitigating risk; budgetary constraints; and differences among the objectives of the various test alternatives.  It is these challenges—along with the metallurgists’ desire to resolve them and get on with the job at hand—that have led to the differences in test procedures that we see in our community today.  Peter's keynote will explore some of the key issues that need to be resolved before we can hope to see universally accepted flotation test standards.
So there is much to look forward to next year in Cape Town, but what are your opinions- what have models and measurements ever done for us?

Wednesday, 8 October 2014

Two giants of mineral processing inducted into Mining Hall of Fame

Two great figures in the world of mineral processing, who both passed away in 2011, will be inducted into the International Mining Technology Hall of Fame at a gala dinner in the Brown Palace Hotel, Denver on February 16.
Professor Klaus Schönert (see obituary of 1st October 2011) developer of High Pressure Grinding Rolls (HPGR) will be inducted in the comminution category.
The acceptance of HPGR has verified the claim from the original research that high pressure comminution improves energy efficiency. The patents which covered his work were for a high pressure comminution process, not a high pressure roller mill by itself. The advance he claimed was for a two-step process of stressing a bed above 50 MPa followed by deglomeration. This was challenged in courts in Germany, USA and Denmark but his patents were approved in every case.
The high pressure grinding rolls which were part of the patents were licensed to ThyssenKrupp Polysius and KHD for use with cement and minerals. There have been more than 700 installations by Polysius and KHD, and many installations by Koppern and FL Smidth. HPGRs are now an accepted part of comminution technology for minerals as well as cement (see full story on MEI Online).
With Byron Knelson in 1992
 
Although I never met Prof. Schönert I did know Byron Knelson very well, and I am pleased to hear that he will be inducted into the concentration category. Byron developed the Knelson concentrator almost 40 years ago, a device which would revolutionise the application of gravity separation in the gold mining industry. The machine has become a fixture in many of the world's most prominent gold mines and the technology is now owned by FL Smidth (see full story on MEI Online).

Monday, 6 October 2014

Precious Metals '15 and Nickel Processing '15- Final Calls for Abstracts

Nickel, gold and PGM prices have looked bleak recently. All the more reason, if you are involved with these commodities, to network with other professionals in these fields to discuss how the processing of these metals can be improved and optimised.

There are now final calls for papers for Precious Metals '15 and Nickel Processing '15, which will be held back to back in Falmouth, Cornwall in May. Full details of the conferences and venue can be found on the posting of 21st July.  If you would like to present papers at these events, please submit your short abstracts no later than the end of next month.

Gyllyngvase Beach, Falmouth
 

Friday, 3 October 2014

Progress on Biohydromet '16

A welcome visitor this morning was Dr. Chris Bryan, lecturer in sustainable mining and mineral resources at nearby Camborne School of Mines (CSM). Chris, one of MEI's biohydrometallurgy consultants, called in for coffee with me and Jon to discuss progress on Biohydromet '16 and the possibility of a tour of CSM's facilities during the conference.

Chris Bryan with Jon and me
Chris is working with Dr. Paul Norris, honorary research fellow of the Environment and Sustainability Institute of the University of Exeter, on the bioleaching of nickel concentrates and they will be presenting a paper on the high temperature bioleaching of pentlandite and pyrrhotite at Nickel Processing '15 in May.

They are also working on the use of Selfrag's electrical pulse fragmentation to improve bioleaching efficiency, and the remediation of water from the old Wheal Jane tin mine using algae.

During the panel discussion at Biohydromet '14 Dr. Norris stressed that academics should continue to search for more useful microorganisms, as there are areas in which those currently available are inadequate for industrial use, solids tolerance in stirred tanks being a notable area, particularly at high temperature. This has stimulated the appointment of a PhD student to bioprospect Cornish mining waste dumps to seek potentially better organisms.

Interesting work and much to look forward to at Biohydromet '16.

Thursday, 2 October 2014

Cornwall's Submarine Mines


The short stretch of coastline in the St. Just region of Cornwall, between St. Ives and Land's End, is designated a Cornish Mining World Heritage site. In this area lies the highest concentration of tin and copper submarine deposits in the world, which were mined at Botallack, Levant and Geevor. Some of the engine houses of these coastal mines were positioned dramatically on the cliffs to allow the mine shafts to be sunk as close as possible to the mineral lodes, which extended beneath the ocean floor in a vast labyrinth of tunnels extending more than a mile out to sea. Positioning the pumping engines nearer sea level also reduced the distance the water had to be lifted before being discharged into the sea.
Last Sunday Barbara and I took a fairly easy six and a quarter mile walk (Elevation Gain 880 feet) commencing at the car park in the small mining village of Pendeen.

 

 
Geevor Tin Mine
The Geevor Tin Mine entrance is on the main road (B3306) between St. Ives and Land's End. Now a museum, the mine was operational between 1911 and 1990 during which time it produced about 50,000 tons of tin concentrate. During the 1970s and 80s I was a regular visitor, with parties of students from Camborne School of Mines, and it was here that many of Richard Mozley's inventions were piloted, such as the Bartles-Mozley Frame, and the Jones HIMS, which was developed by Dr. Jones at CSM, with his undergraduate project student Richard Mozley, to remove paramagnetic hematite from the ground ore.

Froth flotation was introduced to Geevor in 1931, to remove dense sulphide minerals, particularly arsenopyrite, from the cassiterite concentrate, and as we followed the track out of the mine to the coastal path, passing a set of old stamp mills and waterwheel, I noticed a junk yard with the rusting remains of the old banks of Wemco cells.

Stamp battery and waterwheel

Rusting Wemco flotation machines
Arsenopyrite was a problem with most Cornish tin ores, as it is a very dense mineral which reports into the tin concentrate. It had to be removed before smelting, as arsenic seriously embrittles tin metal.  As we proceeded further down the path we encountered the remains of the old Brunton calciners which, prior to flotation, were used to oxidise the arsenopyrite and produce arsenic trioxide which was condensed in a series of labyrinths.



Calcining produced much pollution of the local environment, as well as providing jobs which were probably more dangerous than those working underground.

Digging arsenic soot from the labyrinths
Reaching the coast path we arrived at Levant Mine, with its beam engine still in operation for the tourists. There are other operating beam engines in Cornwall, such as the excellent examples on the road between Camborne and Redruth (posting of 12 June 2010), but Levant's is the only one driven by steam.

Levant Mine
Copper and tin was mined at Levant for generations, and the mine workings extend over a mile out under the sea bed. The Levant Mining Company was formed in 1820 with a capital of £400, though Levant Mine first appeared on a map in 1748. By 1836, 320 men, 44 women and 186 children were employed on the site. In its first 20 years of business, £170,000 was made from mining copper. New technology was introduced to streamline production, and in 1857 the now-infamous man engine was installed. This engine carried men many fathoms up and down the mine, to and from work each day. In 1919, the man engine suffered a disastrous failure when a link between the rod and the engine snapped, killing 31 men. This tragedy was the death knell of Levant mining, which experienced a steady decline until its final closure in 1930.
The coast path west of Levant is heavily eroded, and has been split into several paths by thousands of walkers. I would strongly advise that you stay on the upper paths, however, as the lower paths wander very close to the edge of the 300 ft cliffs and as can be seen on the map of our walk, at one stage we had to retrace our steps as the path was becoming too dangerous to follow.


Of all the submarine mines, the Crowns Engine Houses of the mines at Botallack are the most painted and photographed in Cornwall (see also postings of 30 May 2010 and 8 February 2014). Dramatically perched on Crowns Rocks on the very edge of the precipitous cliff they are a testament to the skills of the 19th century engineers.

Crowns Mines, Botallack
Botallack mines in the 19th century
Botallack is an ancient group of mines formerly worked for tin, copper and arsenic. During the 1870s, as a result of a severe mining depression, Botallack began to make heavy losses, and in 1874 the Crowns section was abandoned.
The lower pumping engine house was built in 1835 and in 1842 a discovery of rich copper ore was made in the 85 fathom (510 ft) level on Crowns Lode, extending out under the sea. This lode was the principal copper producing lode of the mine, and 7,200 tons of copper ore were produced in 1842-1845. When copper mining became uneconomic it was largely tin from the inland parts of the mine that kept the mine going for the next 50 years, its peak production being in the 1860s.
Walking down the steep path to the upper winding engine house, built in 1862,  is a humbling experience, in the knowledge that the miners walked up and down this path daily before disappearing into the bowels of the earth via the Boscawen diagonal shaft to work the lodes up to a mile out to sea.


Returning to the cliff top we passed the ruins of the arsenic calciners and tin dressing floors, and then made our way back to Pendeen cross-country, making a hasty detour en route to avoid a herd of aggressive-looking bulls!

The remains of the Botallack tin dressing floors

Cross country to Pendeen

More Cornish Walks
More on Cornish Mining
More on Cornwall