Tuesday, 21 August 2018

Hi-Tech Metals '18. The option of making it a 3-day event

The two-day Hi-Tech Metals '18 is running back to back with the 3-day Process Mineralogy '18 in Cape Town in November (posting of 4th July). The programme for the final day of Process Mineralogy '18 has been timetabled to concentrate on the process mineralogy of rare earths, lithium and other hi-tech metals, and includes a keynote lecture from Prof. Frances Wall on the importance of mineralogy in the processing of rare earth deposits (posting of 8th January).
If you are travelling to Cape Town just for Hi-Tech Metals '18, you may like to take up the offer of staying an extra day and registering for the conference and the final day of Process Mineralogy '18. Full details are on the conference website.
Delegates at Process Mineralogy '17

Monday, 20 August 2018

Limitations to the commercial application of biohydrometallurgy for the treatment of base metal sulfide ores

Tank bioleaching is an established and competitive technology for treating refractory gold sulfide concentrates, but despite extensive research and development and considerable expenditure, the technology has had limited commercial application for treatment of base metal concentrates. Heap bioleaching is extensively used for commercial treatment of secondary copper ores but is still to be established for recovery of copper from primary chalcopyrite ores.
In the first keynote lecture at Biomining '20 in Falmouth, Dr. David Dew, of Dewality Consultants Ltd, UK, will review tank bioleach technology developed for treating base metal concentrates and discuss the process and engineering factors that determine the design and scale-up, identifying the limiting factors that affect commercial competitiveness. The development of chemical and bioleaching processes for heap leach treatment of primary copper sulfide ores will also be reviewed identifying challenges that limit bioleach performance.
Dr. Dew feels that the hydrometallurgy component of biohydrometallurgy is often largely ignored at conferences concerned with bioleaching, despite the fact that downstream iron removal, metals recovery and waste disposal are key elements that determine the viability of the overall process. He will review some of the standard methods used for metals recovery and the challenges that are imposed on the overall process, particularly relevant to heap leach operations. Considering the limitations and challenges identified, he will then present a case for opportunities where biohydrometallurgy may add value and identifies focus areas for development.
David Dew has 30 years international experience in the development of biohydrometallurgical processes for application in the extraction of base and precious metals. He joined Gencor Ltd., South Africa, in June 1983; in 1990, as Principal Research Metallurgist, he joined the project team responsible for development of the BIOX Process. He took a lead role in the improvement and design of the bioleach reactors, reducing power costs and establishing a methodology for pilot testing and commercial plant design. He was later appointed Manager Process Development at Billiton Plc responsible for leading research in this area. In 2001 Billiton merged with BHP to become BHP Billiton and David was appointed as Global Technology Manager at the Johannesburg Technology Centre, primarily responsible for technology development for the Base Metals Division. David became an independent consultant in 2012 and formed his own company, Dewality Consultants Limited, which he operates from his home in Cornwall. In May 2018 David joined the College of Engineering , Mathematics and Physical sciences, University of Exeter, as a Postdoctoral Research Fellow working part-time for the Horizon 2020 NEMO project, funded by the European Union. The project re-establishes his links with the Camborne School of Mines, from where he graduated in 1979. 

David's keynote is something to look forward to, but in the meantime I am sure that he would appreciate your views on the future of biohydrometallurgy for the treatment of base metal sulphide ores.
#Biomining20 for the latest updates on the conference.

Friday, 17 August 2018

Falmouth Festival Week and a great Cornish Mining Sundowner

The Cornish Mining Sundowner gets better and better, with a great turnout of around 30 yesterday at Falmouth's Chain Locker pub.
Pete and Mary Shepherd, Nick Eastwood, Barbara Wills, Tony Clarke and Steve Barber
Pauline Clarke with Process Mineralogy '18 keynote speaker Frances Wall
BW, Dave Goldburn, Nick Eastwood, Dean Eastbury, Steve Barber, Pete Walsh, Barbara Wills, Dave Dew
The Cornish Mining Renaissance is well under way, and it was good to see so many Cornish Lithium staff, pictured below with Pete Ledingham, Project Manager for the United Downs Deep Geothermal Power project, operated by Geothermal Engineering Limited (GEL). The quest to extract lithium from geothermal brines is now well under way, and Cornish Lithium has recently recruited eight more geologists to the project.
Pete Ledingham (right) with Cornish Lithium staff Adam Matthews, Beth Colgan,
Tom Naylor, George Fry, Lucy Crane and Chris harker
GEL has secured funding of £10.6 million from the European Regional Development Fund to explore the geothermal resources deep beneath Cornwall. With £2.4 million from Cornwall Council and £5 million from private investors, the funding will allow GEL to drill two deep geothermal wells from its site within the United Downs Industrial Estate and build a 1MW pilot power plant to demonstrate the technical and commercial viability of supplying both electricity and heat. Drilling hopefully starts next month, so there will be much to report on in the following months.
It was nice to talk to two young people now embarking on their minerals industry careers. Alex Perry and Sajjad Jabarkhel graduated last month from Camborne School of Mines with honours degrees in Mining Engineering. Alex was Student Union President in his final year, but still managed a first class degree. He is hoping to work in Australia, and I am sure he is set for a very bright future. Sajjad is originally from Afghanistan, and is seriously thinking of staying on at Camborne to study for an MSc in Mineral Processing.
Sajjad and Alex (right) with Tony Clarke, Dean Eastbury, Lucy Crane, Dave Goldburn, Patrick Hegarty and Rob Fitzpatrick
I was pleased to see Rob Fitzpatrick back at a sundowner. Rob is leader of the new MSc in Mineral Processing, which starts next month (MEI Online). He is pictured below with biohydrometallurgists Dave Dew and Paul Norris, and Dave Goldburn of Physical Separation '19 sponsor Holman-Wilfley. Dave Dew will be presenting a keynote lecture at Biomining '20 in Falmouth.
Dave Dew, Paul Norris, Rob Fitzpatrick and Dave Goldburn
Rob tells me that they are expecting between 5 and 10 on the programme this year, but will be pushing next year for better numbers with visits to universities with relevant undergraduate programmes amongst the other forms of advertising.  The programme addresses the industrial need for more trained minerals process engineers, offering a great opportunity for undergraduates with chemistry, engineering, geology and other related backgrounds to enter the exciting field of mineral processing. It provides an excellent opportunity for practical, hands-on learning, featuring the latest developments in mineral processing. Students will also benefit from the wealth of expertise available in industry, particularly from mineral engineering companies based in south west UK. The MSc Minerals Processing programme, including a part-time blended learning option for working professionals, is enthusiastically supported by the CSM Trust, which is currently offering five scholarships of £6k for successful applicants.
This was a great sundowner, part of a great week in Falmouth. The town has been teeming with visitors this week, for the annual Falmouth Festival Week. With its origins in a local sailing regatta dating back at least as far 1837, the Week has evolved into not only a major sailing competition in the south west but also an opportunity for tourists and locals to enjoy the many daytime and evening attractions in the town. The highlight, as always, was the display by the Red Arrows, the RAF's aerobatic team, on Tuesday evening.
The Red Arrows arrive in Falmouth to an eagerly awaiting crowd on Gyllyngvase Beach
Falmouth is certainly a great place to be, and we look forward to being at the next sundowner at the Chain Locker on Thursday September 20th, commencing 17.30.

Twitter @barrywills

Monday, 13 August 2018

Falmouth's beautiful North Helford region

It has been so hot recently in Cornwall that hard coastal path hikes have been put on the back burner for the time being. However, I have managed to cycle most days, and the North Helford region of Falmouth is one of my favourite rides, albeit very hilly (but manageable on my e-bike!). This is also a great area to explore in a few hours by car from Falmouth.
Falmouth lies between the estuaries of two very beautiful rivers, the Fal to the north and the Helford further south, and the North Helford region of outstanding natural beauty starts on the road to the small village of Constantine, from where we can take a 16 mile circular drive along the road which has several offshoots to the Helford River.

Passing by Constantine we reach the Port Navas Creek, one of the Helford's many creeks. Climbing a very steep and narrow hill out of Port Navas village takes us to Budock Vean, from where we head back to Falmouth. The Helford River is a couple of hundred feet below the road, and it is worth the steep descent down to Helford Passage, where there is a small car park next to the famous Ferry Boat Inn. From Helford Passage there is a small ferry to the beautiful Helford Village, and from there a short walk to Frenchman's Creek, the location of the eponymous book and film (see also posting of 10th April 2015).
Port Navas Creek
Helford Passage
Helford Village
Frenchman's Creek
Cornwall not only has a stunning coastline, it also has beautiful gardens, and two of them are on the road back to Falmouth. Trebah is rated in the top 80 gardens in the world, and has a lovely walk through a wooded valley with rhododendrons, magnolias and camellias onto Trebah beach, an idyllic spot on the Helford River. In 1944, the beach was used as an embarkation point for a regiment of 7,500 of the 29th US Infantry Division for the assault landing on Omaha beach, part of the D -Day Landings.

Trebah (source unknown)

Trebah beach
Back on the main road, a short distance from Trebah, is the Glendurgan Garden, owned by the National Trust. This thriving sub-tropical valley garden winds down to the Helford River at the fishing village of Durgan.

The maze at Glendurgan

Durgan village
Heading back to Falmouth, turn right at the Red Lion Inn at Mawnan Smith. Further on it is worth a right turn to Mawnan Church, from where you can park your vehicle and walk through the wood to the coast. A right turn takes you to Toll Head with its spectacular view of the mouth of the Helford River.
The Helford Estuary and the short walk from Mawnan to Toll Head
The Helford estuary from Toll Head
As you complete your journey, you will pass Falmouth's most southerly beaches at Maenporth and Swanpool. Maenporth is overlooked by our favourite Falmouth restaurant, The Cove. What better way to end the day than to have an evening meal in the restaurant with its amazing view of the beach and cliffs?
Maenporth beach
Swanpool beach
Twitter @barrywills

Saturday, 11 August 2018

Thursday, 9 August 2018

Tunnelling, then and now: Cornwall's Great County Adit and the London Super Sewer

I have just finished watching a 3-part BBC documentary on "The Five Billion Pound Super Sewer", which follows workers across London as they race to build an enormous super sewer deep below the Thames. The existing system of tunnels and pipes was constructed in the Victorian era by an ingenious engineer Joseph Bazalgette. This amazing system functioned well for many years, but with London's booming population four times that of Bazalgette's time, the capital's sewage now overflows in heavy rain and the excess waste is diverted to take it out to the sea via the river. From 2023 this excess will be channelled down a 25 km long, 7.2 m wide Thames Tideway Tunnel, preventing millions of tonnes of untreated sewage flowing into the Thames each year.
The ingenuity of modern engineers has to be admired, but no more so than that of the Victorian engineers, who did not have the benefits of tunnelling machines, laser surveying etc. Bazalgette's brick-lined tunnels are a testimony to the skills of the 19th century engineers, but going back even further, there is a remarkable long forgotten system of tunnels in Cornwall, which were built in the 18th century, and hewn from the hard rock using hand tools and gunpowder blasting, long before the introduction of rock-drilling machinery. In 1843 the Mining Journal described the system as “the most extensive, valuable, and systematic undertaking of the kind in Cornwall, perhaps in England, and we believe but few in the world exceed it in importance”.
The Great County Adit is an extensive system of underground near-horizontal tunnels built to drain copper and tin mines in the Gwennap Parish, between Redruth and Bissoe in west Cornwall, once regarded as being "the richest square mile on earth". Construction started in 1748 and it eventually reached a length of nearly 40 miles (65 km) of underground tunnels, providing drainage to over 60 mines at an average depth of 80-100m.
Water has always been the enemy of the Cornish miner, and drainage has been crucial to the survival of Cornwall’s tin and copper mines.  As shafts got deeper, adits (near horizontal shafts) were driven from around 1700 onwards to help drainage. 
Mine drainage adit
Drainage adit: on the right a disused adit, still draining water from a long abandoned mine onto Perranporth beach, Cornwall
However, even after the introduction of the steam engine, major problems remained for the ever deeper mines sited well inland in the St. Day and Gwennap areas.  The water drained needed to be directed to the sea.  The Great County Adit, often known just as the County Adit, provided the solution.  The brainchild of John Williams, owner of Poldice Mine, he and "adventurer" Sir William Lemon drove the project forward.  Begun in 1748, by 1760 it was draining Poldice Mine into the Carnon River which flows into Restronguet Creek, one of the River Fal's many creeks.  By 1778 it had been extended to nearby Wheal Busy and Wheal Peevor.  Eventually it drained more than 60 mines in the Redruth and St. Day mining areas discharging around 13 million gallons a day into the river via its portal below the hamlet of Twelveheads.  In the 1860s over thirty Cornish beam engines pumped into the adit, more than were used by the whole of continental Europe and America combined.
The high volume of water flowing out of the adit contributed to the success of at least 15 industries downstream from the portal at Twelveheads. There were tin dressing plants, two major arsenic producers, two blacksmiths, a small iron foundry, a corn mill and an ochre plant, the latter making use of the hematite flowing down from the adit. This vast amount of water, from the joining of several rivers and the County Adit, powered water wheels and was used in washing, but ironically the adit was the instrument of the decline of Devoran, the port on the Restronguet Creek which served the mines upstream via the Redruth and Chacewater railway.  Disastrous floods in 1876 caused the neglected County Adit to release thousands of tons of water, carrying rubbish and silt down-river to Devoran, blocking navigation to all but the lower quays.
Although the mines have long been abandoned, and the adit is no longer maintained, it still drains the old workings, and in the summer of 1980 the flow was estimated at around 500,000 gallons per day,  the river downstream still showing evidence of contamination by heavy metals.
Carnon River, Cornwall
The Carnon River, near Bissoe, August 2018
The County Adit portal in 1978
Photo: Roy Morton
It is impossible to estimate the cost of driving the County Adit, but it is likely to have been around £250,000, a considerable sum at the time. However, this amount is relatively tiny considering the millions of pounds saved by the mines due to its efficient draining and the reduced cost of pumping to adit rather than to surface.
The Great County Adit is a reminder of a glorious past where Cornwall dominated world metal mining, and its story has been told in detail by Alan Buckley, an ex-miner with extensive experience at South Crofty and Geevor mines. His book, The Great County Adit, is published by the Trevithick Society, and the photo on the front cover shows the adit portal at Twelveheads in 1978.
Twitter @barrywills