Ucore Rare Earth - USA braucht seltene Erden HREE

Gareth Hatch:
Source: Brian Sylvester of The Critical Metals Report  (11/22/11)

http://www.theaureport.com/pub/na/11751  

http://www.goldseiten.de/content/diverses/...toryid=17947&seite=1  

eindrucksvoller Artikel Video ;-)
Es heißt eigentlich nur sich die gut aufgestellten "Perlen" mit hohen HRE Anteilen wie z.b. Ucore,Avalon,Tasman u.a. rauszupicken, in der Hoffnung,dass die es bis zur Produktion schaffen!

Bei MCP kann es noch ganz schön eng werden mit den 1% Heavy Anteilen in der Mountain Pass Mine und die leichten Erden sind überall zu finden.
Ich Zweifel auch sehr,ob an der Geschichte mit den neuen Hre Funden in der Nähe der Mountain Pass Mine etwas dran ist....
Andererseits hat der Autor vergessen, dass MCP schon ein wenig Geld verdient und es in die weitere Phönix Ausbaustufen stecken kann, sprich reinvestieren kann (Aufkäufe?)!
Ob das Geld aus dem Gewinn dafür reichen kann, wird sich zeigen...

MfG  

By Michael Montgomery,  Mon, Nov 21, 2011
http://rareearthinvestingnews.com/5477/...MPAIGN&utm_medium=email  

December 19, 2011

http://www.businessday.com.au/business/...xporter-20111218-1p0rj.html  

"Rare earth giant excluded from exporters list"

December 16, 2011
http://www.china.org.cn/business/2011-12/16/content_24173832.htm  

"Molycorp has been very successful in raising money. Frontier has about $50 million (M), and it only needs about $20M to finish its feasibility study by next year. Rare Element Resources is also in a very good cash position. It has about $74M in cash, and it needs a fraction of that to complete its feasibility study by the end of next year as well; it can even extend it. Hypothetically, even if there were a recession for the next two years, I think these companies would have enough cash to complete their studies.

Other companies that probably have sufficient cash for a year: Tasman Metals Ltd. (TSM:TSX.V; TAS:NYSE.A; TASXF:OTCPK; T61:FSE), Ucore Rare Metals Inc. (UCU:TSX.V; UURAF:OTCQX) and even Matamec. More than 12 months would probably not be possible for those three, however. "

 

aus:

 

Luisa Moreno: The Age of Rare Earth Metals  

 

http://www.resourceinvestor.com/News/2011/12/...are-Earth-Metals.aspx

 

R. Colin Johnson
12/16/2011 2:12 PM EST
http://www.eetimes.com/electronics-news/4233358/...or-next-five-years  

China Increases Rare Earth Export Quota for First Half of 2012[/b]

Thu, Dec 29, 2011

By Michael Montgomery—Exclusive to Rare Earth Investing News


The Chinese Ministry of Commerce announced its rare earth export quota for the first half of 2012 on Tuesday. The quota, which is the first increased in six years, is set at 10,546 tonnes. The Ministry also announced its decision to classify the rare earth minerals into two categories: heavy and light rare earths. The change, which has been much anticipated by analysts, may prove to be a positive step for end users as the two groups have vastly different demand levels.

The Ministry of Commerce stated that the export quota for 2012 would remain flat, in order to boost demand while keeping supplies stable. While the total export quota numbers seem to have been cut, the numbers are slightly misleading.

“The first tranche of rare earths export quotas for next year had been set at 10,546 tonnes, but that figure only included those enterprises that had passed a series of stringent environmental inspections,” reported Aizhu Chen, for Reuters.

In addition, the Ministry is holding 14,358 tonnes in reserve for the rare earth producers still going through inspections. Currently 11 companies in China have passed inspections with another 21 companies scheduled to complete the process by July 2012. If a company fails to pass the inspection, their quota would not be eliminated, just re-allocated to another firm.

The additional tonnage would bring the first half quota up to a total of 24,904 tonnes.

The increased tonnage will more than likely bring prices down even further which may boost demand. Demand levels are a serious concern for Chinese producers because only 49 percent of the quota was used in 2011, severely hurting producers’ bottom line.

Though the full-year quota is still unknown, the Ministry stated that the batch of quota’s accounts for 80 percent of the full-year’s total. If the statement is true, the full-year quota would come to a total of 31,130, an increase of roughly 3 percent.

Heavy and light rare earth classifications

A major change in China’s 2012 quota is the division of the rare earth metals into two groups: light and heavy rare earths. The quota allocates 21,700 tonnes of light rare earth, and 3,204 tonnes of heavy rare earth for export in the coming year. The new classification may be an important, stabilizing factor for the market.

Demand for light rare earths such as neodymium has consumed the bulk of the quota in previous years as many of the heavy rare earths were in short supply. The change may stabilize and increase the supply of heavy rare earths. For end-users the stability and known quantity of heavy rare earth available allows for their business to plan for the future. A feature missing from the rare earth market during the supply squeeze over the past few years.

The change in the quota is also an effort to discourage producers from exporting the elements with the highest price alone in order to increase profits.

“That strategy had led to the price of cheaper rare earths, such as cerium and lanthanum, rising much faster than other rare earths early in the year, because of restricted supply from China,” reported Ajay Makan, for the Financial Times.

While cerium and lanthanum have risen dramatically, they were not trading on fundamentals. When the demand fell, these elements’ prices fell dramatically due to the glut of supply. The Ministry is hoping these new regulations minimize this volatility.

Mining share prices fall

The announcement from Beijing has affected the share prices of many rare earth mining companies, as lower prices for rare earths are expected in the first half of 2012.

On the day, shares of Molycorp (NYSE:MCP) were down 14.14 percent to $24.04. While Rare Element Resources (NYSEAMEX:RES) lost 11.57 percent down to $3.21 per share.

Australian rare earth miner Lynas Corp. (ASX:LYC) fared better in today’s trading, losing only 3.43 percent down to $1.10 per share.


http://rareearthinvestingnews.com/5772/...MPAIGN&utm_medium=email  

Energiewirtschaft und Elektromobilität könnten Rohstoffressourcen »sprengen«

elektroniknet.de | 03. Januar 2012

Die Zukunftstechnologien im Bereich Energiewirtschaft und der Mobilität lassen die Nachfrage nach Seltenen Erden bis zum Jahr 2030 überproportional steigen. Das ist das zentrale Ergebnis eines Forschungsprojektes zu ressourcenpolitischen Aspekten der Elektromobilität, das das Öko-Institut mit Daimler, Umicore und der TU Clausthal im Auftrag des Bundesministeriums für Umwelt, Naturschutz und Reaktorsicherheit (BMU) durchgeführt hat.

Daher gilt es alternative Technologiekonzepte zu entwickeln, die ohne diese wertvollen Rohstoffe auskommen beziehungsweise effiziente Lösungen für deren Recycling zu finden. Die Projektpartner identifizierten zunächst 12 Metalle, die besonders wichtig für die Herstellung von Elektroautos sind. Diese sind Kupfer für alle Komponenten, Seltene Erden wie Neodym, Praseodym, Dysprosium und Terbium für die Elektromotoren sowie Indium, Gallium, Germanium, Gold, Silber, Platin und Palladium für die übrigen Komponenten wie Leistungselektronik. Das Projektteam bemaß anschließend den möglichen zukünftigen Bedarf durch die Elektromobilität an den prioritären Metallen.

»Wir sehen für eine Reihe der untersuchten Metalle einen zum Teil stark steigenden Bedarf bis zum Jahr 2030. Einer der Gründe dafür ist die Elektromobilität, wenn deren Marktdurchdringung so verläuft, wie sie in globalen Strategien skizziert oder innerhalb der Nationalen Plattform Elektromobilität angedacht wird«, erläutert Dr. Matthias Buchert, Projektleiter am Öko-Institut die Ergebnisse der Szenarienanalysen. »Am markantesten zeigte sich der Anstieg bei Dysprosium.«

Dem knappen Angebot an Dysprosium, das heute vorwiegend in China produziert wird, steht ein stetig wachsender Bedarf gegenüber: Zum einen für die Elektromobilität zum anderen aber vor allem in Anwendungsbereichen wie etwa der Herstellung von Neodym-Eisen-Bor-Magneten, die für die stark wachsende Produktion von Windkraftanlagen benötigt werden. Die Ergebnisse zeigen weitere, klare Tendenzen: Im Vergleich zur gesamten Primärproduktion der Metalle im Ausgangsjahr 2010 fielen vor allem die Seltenen Erden wie Neodym, Praseodym und Terbium sowie Gallium als besonders relevant auf. So kommt Gallium neben der Elektromobilität auch in der Photovoltaik oder in LEDs zum Einsatz.


Versorgungsengpässe eindämmen, aber wie?

Um mittel- und langfristig Versorgungsengpässe einzudämmen, nennt das Öko-Institut zwei wesentliche Strategien: Zum einen müssen Ressourcen effizienter eingesetzt werden und wo möglich durch andere Technologien ersetzt werden. Zum anderen müssen jetzt Recyclingstrategien für Seltene Erden und andere kritische Metallen entwickelt und zur Marktreife gebracht werden, um auf lange Frist Verknappungen zu vermeiden.

»Die Rückgewinnung wichtiger Edelmetalle zum Beispiel aus den Katalysatoren von Altautos kann bereits heute die Nachfrage und die Umwelt deutlich entlasten«, so Buchert weiter. »Gerade die im vergangenen Jahr stark angestiegenen Preise auf den Weltmärkten für Seltene Erden zeigen die Potenziale für ein neues Herangehen an das Bewahren der Rohstoffe, die uns nicht unendlich zur Verfügung stehen.«

Darüber hinaus müssen neue Lagerstätten vor allem von Seltenen Erden erkundet und erschlossen werden, um kritische Situationen wie durch eine nahezu ausschließliche Förderung in einem Land zu vermeiden. Ein umweltverträglicherer Bergbau, Recycling, Substitution sowie die effiziente Förderung und der Einsatz von kritischen Metallen wird eine permanente Aufgabe für den Forschungs- und Technologiestandort Deutschland sein, fasst Prof. Dr. Daniel Goldmann zusammen. »Nur so können wir die »ökologischen Früchte«, die mit der Verbreitung der Elektromobilität angestrebt werden, tatsächlich ernten«.


Informationen zur Forschungsmethodik

Für die Berechnung in verschiedenen Szenarien – Innovationsszenario, Recyclingszenario, Substitutionsszenario – setzten die Wissenschaftlerinnen und Wissenschaftler auf den globalen Marktszenarien von McKinsey 2009 für die Entwicklung der Elektromobilität auf. Diese wurden verknüpft mit differenzierten Mengendaten der prioritären Metalle zu den wesentlichen Komponenten der unterschiedlichen Antriebstypen (Hybrid-, Plug-In-, Range-Extender-, Batterieelektrisches-, Brennstoffzellen-Fahrzeug) der Elektromobilität. Das Projektteam diskutierte die ausgewerteten Daten für den spezifischen Rohstoffbedarf der jeweiligen Komponenten mit externen Experten in Fach-Workshops.

http://www.elektroniknet.de/e-fertigung/news/...den_als_Stolperstein/  

Sunday, January 01, 2012

Tear up those latest projections for supply-demand balances for rare earths. The Japanese have just moved the goal posts once again. There is breaking news from three large Japanese corporations - Mitsubishi, TDK and Toshiba - and they again demonstrate Japan‘s determination, led by new efforts headed by the Ministry of Economy, Trade and Industry, to step up research to develop magnets that are powerful and heat-resistant but using common materials rather than REE. The ministry plans to rope in automakers, magnet manufacturers, universities and public research institutions to help bring this off.

In its latest roundup, the Nikkei news service reports that Mitsubishi Electrical Corp has developed a motor for electric vehicles and other products that uses no rare earths at all. The report says Mitsubishi, working with the New Energy and Industrial Technology Development Organization (NEDO), has come up with an automotive motor based on the principles of electromagnets - bypassing rare earth oxides. It concedes that the new motor is less efficient than conventional ones during acceleration but performs comparably after reaching what it calls stable speed.

This comes as Mitsubishi has signalled it plans to launch an electric light truck this year. Owners will be able to recharge the battery using normal household power outlets. Mitsubishi will be targeting farmers, contractors and others with this new vehicle. It sees this product as boosting its overall electric vehicle sales, and has set itself a 2012 sales goal of 42,000 worldwide, double those of the previous year. The new truck will go on the market at the local equivalent of $US19,200.

Mitsubishi is also working on its next generation Outlander SUV. It is expected that a hybrid version could be available in 2013.

Meanwhile, those who are following every development involving that key REE, dysprosium, will be interested to learn that TDK Corp has developed a dysprosium-free permanent magnet. The Nikkei says this has been achieved by changing the method of processing molecules. TDK sees the new magnet as providing the same strength as those products using dysprosium and intends having the product ready for use in automotive motors by 2014.

Another report from Tokyo says that Toshiba is also working to replace dysprosium from its magnet technology, but is not shunning REE altogether. Rather it plans to use samarium - a development that will please Molycorp and Lynas, both of which have samarium in their REE mines at Mountain Pass and Mt Weld respectively.

Posted by Robin Bromby at 07:13:31 PM inEditor, Robin Bromby, Intel

http://www.raremetalblog.com/2012/01/...ork-to-bypass-dysprosium.html  

China's tight grip on rare earth elements supply may loosen as other deposits around the world come to fruition in 2012. In this exclusive interview with The Critical Metals Report, Jon Hykawy, head of global research with investment bank Byron Capital Markets, discusses the supply and demand fundamentals that are driving his predictions for the New Year.  

Source: Brian Sylvester of The Critical Metals Report  (1/3/12)

Auszug:

TCMR: Your price deck changes led to you halving your 12-month target on Ucore Rare Metals Inc. (UCU:TSX.V; UURAF.OTCQX) to $0.80 from $1.30. Nonetheless, you still have a Speculative Buy rating on the junior. Tell us about that dramatic revision.

Jonn Hykawy: That was motivated by the fall in our HREE prices and the belief that dysprosium and terbium will potentially be in oversupply in the future because of new types of deposits and technological changes.

Ucore wasn't the only company that suffered that change. In fact, our Matamec price at the time was halved as well. We still think that Ucore has the right address. It is an HREE deposit in the U.S. We think the U.S., specifically the Department of Defense, has a very vested interest in making sure that there is a heavy rare earths supply within its borders. State and federal governments are very supportive of this project. It's a straightforward project in the sense that access is good, capital expenditures should remain reasonable and it's more than economical, even with our long-term price deck.

...

http://www.theaureport.com/pub/na/12107

 

January 4, 2011 – Ucore Rare Metals Inc. (TSX-V: UCU | OTCQX: UURAF; “Ucore” or the “Company”) is pleased to announce the appointment of Ken Collison as Chief Operating Officer. Mr. Collison holds a B.Sc. in Mining Engineering from the University of Saskatchewan and a Masters of Engineering in Mining from the University of Saskatchewan. He was the Chief Operating Officer of Blue Pearl Mining/Thompson Creek Metals from 2005 to 2009, and was part of the team that purchased Thompson Creek Metals and built it into one of North America’s premier molybdenum producers. He has previously held the positions of Vice President at Crandon Mining Corporation and Coeur Alaska, the Alaskan subsidiary of Coeur d’Alene Mines. He has extensive experience in mining operations, permitting and preparation of mining feasibility studies.

Mr. Collison replaces Harmen Keyser in the capacity of Ucore’s senior technologist and will be assembling a team of mine development specialists focused on the near term development of the Company’s flagship heavy rare earth property at Bokan Mountain Alaska.

“We’re delighted that Mr. Collison has elected to join the Ucore team in a formal capacity,” said Jim McKenzie, President and CEO of Ucore. “He’s an accomplished mine development specialist with a reputation for bringing advanced stage properties to production on minimal turnaround and in a highly efficient and economical manner. He has a tremendous track record, is highly regarded in the mine engineering community, and brings a significant depth of experience managing and developing mining operations in Alaska. Mr. Collison’s appointment is additionally a benchmark event for Ucore, as we transition from advanced mineral exploration into fast track mine development. We’d also like to take this opportunity to thank Harmen Keyser for his invaluable contribution in taking early stage exploration activities to the threshold of mine development.”

http://ucore.com/ucore-appoints-collison-as-chief-operating-officer  

Der Mann ist kein Unbekannter:

Er gehörte zu jenem Drei-Mann-Team, welches im Jahre 2006 unter dem Namen Blue Pearl Mining den Minengiganten Thompson Creek Metals übernahm.
Der Deal wurde damals als "Mining Coup of the Decade" bezeichnet.

Diese Tatsache berechtigt offenbar zu einigen Vorschusslorbeeren...

http://de.advfn.com/...cu&p=0&t=1&vol=1&cb=1127143677

BACKGROUND:

Mr. Kenneth W. Collison, Ken, P.Eng., B.Sc., M. Eng (Mining) has been the Senior Vice President of Project Development at Avanti Mining Inc. since December 2009.
Mr. Collison has been Technical Advisor at Huakan International Mining Inc. (formerly Merit Mining Corp.) since July 2010. He has over 40 years of experience in the mining industry and has senior responsibility for mining operations and environmental affairs.
He has extensive experience in operations as well as permitting and preparation of feasibility studies. He served as the Chief Operating Officer of Thompson Creek Metals Company Inc. (formerly, Blue Pearl Mining Ltd.) from April 1, 2005 to September 30, 2009.
He served as an Engineering Manager for the Department of Transportation & Public Facilities for the State of Alaska since 2004 with particular emphasis on highway and marine terminal projects and Environmental Impact studies. Mr. Collison served as the Manager of Village Safe Water Program for the State of Alaska from 2001 to 2004. He served as Vice President at Crandon Mining Corporation, Rhinelander, Wisconsin from 1994 to 1996 and Vice President/General Manager of Coeur Alaska (Alaskan subsidiary of Coeur d'Alene Mines) from 1996 to 2000.
From 1996 to 2000, he served as Vice-President and General Manager of Coeur d'Alene Mines Corp. and was responsible for the development of the 200,000 ounce per year Kensington Gold Mine and held numerous senior positions with Rio Algom. He served as the President of President of Collison Minecon Inc. He served as the President of Rio Kemptville Tin Company, Rio Algom's East Kemptville tin project in Nova Scotia.

He was part of a three man team that purchased Thomson Creek Metals and built it into a one of North America's premier molybdenum producers.

He served as President of Nova Scotia Chamber of Mineral Resources. From 1980 to 1994, Mr. Collison held various management positions with Rio Algom Limited. He has been a Director of North American Tungsten Corp. Ltd. since November 2, 2009. He has been a Director of TintinaGold Resources Inc. since May 3, 2010. He has served as a Director of the Mining Associations of Canada and BC. He served as a Director of Nova Scotia Chamber of Mineral Resources. He served as Director of Merit Mining Corp. since December 22, 2009.

He serves as a Member of Technical Advisory Committee at Aurcana Corp. His community service earned him the "Citizen of the Year" award from the Yarmouth, NS Chamber of Commerce. He is a Professional Engineer. Mr. Collison holds a B.Sc. in Mining Engineering and a Masters of Engineering in Mining from the University of Saskatchewan.  

"Five Rare Earths Crucial for Clean Energy Seen in Short Supply"

By Jim Snyder - Jan 5, 2012 8:10 PM GMT+0100
http://www.bloomberg.com/news/2012-01-05/...seen-in-short-supply.html  

"Is The Resurrection Of Undervalued Miners in 2012 Beginning?"

January 6, 2012 5:07 pm
...

"This week the rare earths are emerging from their  second half 2011 slumber.  It is felt that they will lead the upcoming recovery.  This week certain of the rare earths are producing impressive percentage gains as an augury of things to come.

As of this writing we believe Tasman(TAS) (NYSEAMEX:TAS) and Ucore(UURAF) (PINK:UURAF) are leading the pack.  These stocks possess unique features to which attention must be paid.  Ucore owns a mountain of high grade heavy rare eaths right here in the United States.   Tasman dominates the European Continent as the only possessor of a 43-101 resource with heavy rare earths and a high percentage of the vital element dysprosium.    Rare Element Resources (NYSEAMEX:REE) released news that they have just expanded their resource to show potential for heavy rare earths.  The market is reacting favorably as it has nearly doubled in one week.

Ucore, Tasman and Rare Element Resources have broken downtrends on record high volume the first week of 2012.  Molycorp (NYSE:MCP) has underperformed and still needs to break above resistance as it is lagging the sector."

...
http://wallstreetsectorselector.com/2012/01/...e-fxi-nlr-tsx-ccj-fxe/  

Canaccord Morning Coffee (1/5/12)
"Ucore Rare Metals Inc. announced the appointment of Ken Collison as chief operating officer; Collison was the COO of Blue Pearl Mining/Thompson Creek Metals from 2005–2009 and was part of the team that purchased Thompson Creek Metals and built it into one of North America's premier molybdenum producers. He has extensive experience in mining operations, permitting and preparation of mining feasibility studies; Ucore stated that Collison will be assembling a team of mine development specialists focused on the near term development of the company's flagship heavy rare earth property at Bokan Mountain, Alaska."

Jon Hykawy, Byron Capital Markets (1/5/12)
"Ken Collison is joining Ucore Rare Metals Inc. as CEO. . .this is a very strong hire for Ucore: Mr. Collison knows Alaska and all the key figures in mining in Alaska, and that familiarity with the physical and political environments should not be underestimated. More importantly, this illustrates in no uncertain terms that Ucore is putting the team in place to build a HREE mine at Bokan Mountain."


http://www.theaureport.com/pub/co/409#quote  

Ucore Confirms Widespread Rare Earth Mineralization In Central Alaska

January 16, 2012- Halifax, Nova Scotia
http://ucore.com/...pread-rare-earth-mineralization-in-central-alaska  

http://www.kaiserbottomfish.com/i/jk/OtherCharts/REOSupDemPrices.gif

http://www.molycorp.com/Portals/0/Documents/...ly_Demand_Fall2011.pdf  

Jan 13th, 2012
     
"When it comes to a U.S.-based RE play, Ucore Rare Metals (UCU: TSX-V) also took a share price swoon in December, down into 35-cents territory. It's now trading in the 45-cent range.
Ucore recently announced the appointment of Ken Collison as chief operating officer.  I've met Ken on a couple occasions, and he's a solid, outstanding, super-savvy mining guy. He knows what has to happen to turn Bokan Mountain, Alaska, into a working mining operation. So that's a very positive step for Ucore.
Meanwhile, I previously reported on my visit to the Hazen Research laboratory near Denver. There, the world-class Hazen technical staff is working on processes and procedures for turning the Bokan ore into useful RE atoms. That too is positive.
Finally, I should mention that Ucore has another team of world-class chemistry guys working on the RE separation issues. I've met them and discussed the space-age technology that they're bringing to bear. But I agreed not to give away any identifying information. All I can say is that they're unbelievably good.
Thus, I expect to see further good news from Ucore as the year moves on. Ucore is a buy at the current pricing."

http://www.stockhouse.com/bullboards/...5031&l=0&pd=2&r=0  

Ucore Rare Metals plowed through the market gates on Monday following the release of rare earth exploration results from Alaska.

Author: Kip Keen
Posted:  Tuesday, 17 Jan 2012

HALIFAX, NS -  

The shareprice of rare-earths explorer Ucore Rare Metals (TSX-V: UCU) surged yesterday after it announced assay results of gravel and sand samples from its Ray Mountain project in Alaska.

Ucore climbed 11 percent to C$0.44 on strong volumes early in the trading day on Monday.

Ucore said the results suggested "potential economic grade concentrations" of rare earths elements (REE) and tin at its upper Kilolitna River, Ray River and No Name Creek targets.

The junior took 5-gallon bucket samples most of which Ucore then concentrated on a shaking table. Ucore said concentrates graded as high as 50 percent tin, 10 percent total rare earths and between 0.01 to 1 percent tungsten, tantalum and niobium. Heavy rare earths made up between 15 and 25 percent of REEs in the bulk of its samples, Ucore said.

The Ray Mountain alluvial deposit is 100 metres thick in places, Ucore said.

Heavy rare earths (HREE) are the chief focus of Ucore, which goes by the slogan "America's Dysprosium & HREE Leader." Ucore owns the Bokan rare earth project, also in Alaska, where it holds 4 million tons @ 0.75 percent total rare earths.

It is in the midst of conducting a scoping study of Bokan.


http://www.mineweb.com/mineweb/view/mineweb/en/...tail&pid=102055  

"Rare Earths: Separating The Wheat From The Chaff"

Byron W. King | Agora Financial January 13, 2012  

http://ucore.com/ByronKing_Jan13_2012.pdf  

http://netzagentur.de/sdr/sdr-km-2012.pdf  

Ucore Releases 2011 Bokan Drill Results Pending Augmented Resource Calculation

January 23, 2012 – Halifax, Nova Scotia

http://ucore.com/...ll-results-pending-augmented-resource-calculation  

by James C. Barker and Bradley S. Van Gosen

Mining Engineering Magazine VOL. 64 NO. 1
January 2012

http://ucore.com/MiningEngineering%20Jan2012.pdf