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By E. E. Maurer

Kerr-McGee has operated the Ambrosia Lake uranium mill since startup in 1958. Tonnage milled per day has varied from 3500-7000 tons. The mill capacity is currently rated at 7000 tons per day. The process consists of two parallel circuits following crushing and sampling, \\lhich include open circuit rod mill grinding, sulfuric acid leach, cyclone classification, and counter-current washing circuits of sand classifiers and slime thickeners. Pregnant solution is clarified and polished by precoat pressure leaf filters prior to amine solvent extraction. Yellowcake is precipitated from the pregnant strip solution with ammonia, filtered and dried.

Jan 1, 1972

By M. Sengupta

Surface mining in arctic regions is characterized by many unique problems. Continuous and discontinuous permafrost (perennially frozen ground) occurs in most of the arctic and subarctic areas. Permafrost presents special problems of slope stability. Stability of permafrost depends on its temperature, moisture content, and material type. Permafrost slope fails due to solifluction, disturbance of ice-rich slopes, and liquefaction. Drilling and blasting of frozen ground present special problems. Depending on their degree of saturation with water, freezing soils and rocks have a number of important characteristics that affect blasting efficiency. Metals used in mining equipment and mining structures require special selection. At low temperatures, many steels lose most of their normal ductility and toughness (resistance to brittle fracture). This paper discusses engineering solutions to unique problems of arctic mining.

Jan 1, 1988

By Bernie W. Martin, Duncan MacLennan

Building a new tunnel to accommodate CN North America's needs for double stacked container traffic for the next 100 years presented new and unprecedented challenges. Innovative approaches to contracting, especially the Negotiated Compressed Process (NCP), TBM design, project management, and the regulatory and approval process, were all required to deliver a new tunnel to meet the needs of CN North America within the approved completion schedule of 39 months compared to a traditional approach of 45 to 48 months. The NCP resulted in trimming 6 to 9 months from the project schedule, at a great saving of direct and indirect costs. The Negotiated Compressed Process is an innovative formalized approach to risk sharing for complex infrastructure projects. Ads were placed in the international trade journals and a short list of "approved" contractors and suppliers was developed. The approval process for this international project involved contacts with over two hundred agencies, departments and interested stakeholders.

Jan 1, 1995

By Ray A. Rothrock

The in situ mining of uranium is the process whereby chemical lixiviant is injected by means of wells into, and flowed through, an ore body. The lixiviant reacts with uranium which has been previously oxidized making the uranium soluble. The solution is then brought to the surface by means of producing wells. In situ mining disturbs the ground-water quality in the immediate area. Since ground water is a natural resource used by man, care must be taken not to allow the lixiviant to escape the local mining area. Also, when the ore body is mined out, the area should be restored to as near its original state as is reasonably achievable. The return of ground-water quality to its original state can occur naturally over a long period of time or be enhanced using appropriate technological means.

Jan 1, 1981

By Richard Campbell, Claire Pirona, MEHMET KIZIL, Ismet Canbulat, Stephen Giese, Ravindu Goonawardene, Edward Steed, Serkan Saydam

The Australian longwall mining industry spends millions of dollars per year on proactive and reactive ground consolidation applications across most of the operations currently in production. The design and effectiveness of the applications and products vary widely and are based predominantly on-site precedence or what were considered successful applications at other sites in similar situations. In the continual improve the effectiveness of how consolidation products are used and when by enhancing our knowledge of the mechanical properties of products used in underground coal applications and applying this increased understanding to geotechnical design. One of the current challenges to further developing more appropriate and accurate geotechnical design methods for consolidation activities is the lack of standardised materials testing and knowledge of rock mechanics data on in situ performance. The lack of industry standardisadesign of consolidation programs, with a reliance on experience-based guidance for rockmass consolidation design. consolidation products. The program was designed to provide the industry with a set of geomechanical property index tests and a data set that can be utilised by rock mechanics engineers as baseline information for product evaluation and engineering design. The laboratory work undertaken is critical to understanding the exact small-scale mechanical properties of these products and testing was carried out at Monash University for various states of curing of each product. Recognising that the speed at which a mixed product develops its desired properties to act as a support element in underground coal mines is critical to its serviceability. This paper presents the testing rationale proposed, the testing results, and a framework for how the data set can be used to improve the engineering basis for ground consolidation design, in terms of expected rockmass performance under various mining conditions and application parameters.

Jun 25, 2024

By C. Iglesias

Innovation in the tilemaking ceramic industry is stressing properties like powder flowability, ability to toughen green tiles, so turning technological requirements of ball clays ever stricter in terms of plasticity, dispersion in water, rheological behavior, workability in the green state, refractoriness and firing colour. Technological performance of ball clays was improved by taking as benchmark the highest quality raw materials on the market. The mineralogy, plasticity, methylene blue index and ceramic response of the Patagonian ball clays are analogous to those of European clays, but improvement is needed to approach the highest quality materials. On this basis, the Frente A, Super, Puma, and Lote 8 deposits were selected and their characteristics enhanced by additions of highly plastic and white-firing corrective clays targeted on the benchmark. Porcelain stoneware formulations, containing improved ball clay mixes, were experimented at both laboratory and industrial scale. The improved ball clays behave like the best raw materials currently used, although modest changes occur in the mechanical properties, water absorption and whiteness of the fired products.

Jan 1, 2010

By P. Lan

Gold is often associated with arsenopyrite in many refractory gold ores. The selective recovery of arsenopyrite by flotation is therefore necessary in order to maximize the recovery of gold. However, the complexity of arsenopyrite flotation often makes it difficult to obtain a high recovery from real lean gold ore. This paper presents the results of arsenopyrite flotation by ultrasonic pretreatment in micro flotation experiments and bench scale flotation tests. The tests showed that pure arsenopyrite exhibited low natural floatability due to the oxidation on the mineral surface under ambient conditions. Using ultrasonic pretreatment, the oxidation film was ruptured and the floatability was enhanced greatly. The presence of Fe (III) was found to inhibit the flotation of arsenopyrite and this depression was also removed by the ultrasonic pretreatment. This result explained why the arsenopyrite in real ore is often difficult to float and how ultrasonic pretreatment can effectively improve the arsenopyrite flotation in real gold ores. Guanidine (GMM) was found to be a superior collector for arsenopyrite in acidic medium and xanthate in alkaline medium.

Jan 1, 1998

By Evan Brinkerhoff, Steve Chorley

The largest hard rock TBM ever to bore in the USA, an 11.6 m diameter Robbins Main Beam TBM, recently underwent a planned in-tunnel diameter change to a more compact 9.9 meters. The first-of-itskind conversion process for the Main Beam TBM was undertaken 2.8 km into the bore and was not done inside a shaft or pre-excavated portal. This paper will detail the unique dual-diameter machine designed for the Mill Creek Drainage Relief Tunnel in Dallas, Texas, USA, machine performance, and successful size conversion process that took place in early 2021—a process that utilized the four C’s of construction to enormous benefit: Communication, Cooperation, Collaboration and Coordination.

Dec 1, 2022

By C. W. Schultz

The Alabama tar sands of the Hartselle Sandstone formation present a more difficult problem in primary extraction than do the Athabasca tar sands. In contrast to the Athabasca tar sands, the Alabama tar sands are "oil wetted" and the contained tar, or bitumen, is of much higher viscosity. A physical beneficiation scheme was developed in which clean sand from an external source was used as a scrubbing medium. High intensity scrubbing liberated the tars which are readily recovered by froth flotation. Locked cycle tests have shown that, after the use of an initial ration of clean sand, the system produced enough new clean sand to be self sustaining.

Jan 1, 1992

By D. A. Dahlstrom

Energy costs have had a serious impact on all basic industries today. This is due to the significant amount of energy that is used to convert natural resources into usable products. Other factors such as transportation with its major energy requirement and materials employed in processing that have already required significant energy input for their manufacture accordingly influence delivered cost to the user. The farmer is a good example of this. While his large capital investment for land, machines, and buildings is highly impacted by today's interest rates, his chemical fertilizer, herbicides, and pesticides as well as those same machines and transportation costs for his products have also been seriously affected by energy costs. With the many unit operations involved in mining and mineral processing, several of which require significant inputs of energy, one can only conclude that this industry has experienced a great increase in percentage of total cost for energy alone. Fuerstenau (1975) indicated that the minerals industry used about 12.5% of the total energy produced in the US. McNulty (1983) listed the total energy requirements for the production of 0.9 t (1 st) of various metals including the energy consumed in the manufacture of supplies employed, such as tires, explosives, chemicals, grinding media, etc. (Table 1).

Jan 1, 1987

By S. Angioletti

This paper addresses strategic investment decisions when they are nested in a project development format where each project is implemented in phases and each phase is approved to move on to the next phase only if certain technical and economic requirements are met. This configuration is sometimes referred to as a ?Project Portfolio?. Mining companies maintain project portfolios in their exploration investment plan. This study proposes a procedure to best manage an exploration project portfolio including technical and economic uncertainties. The procedure may support decision makers in a simple and intuitive way, while maintaining the rigor and precision required by the rather large amount of financial resources typically called for by mining projects. The procedure was tested in a real case study of a gold mining company and its exploration projects portfolio. The procedure uses the following approaches: i) investment valuation methods under technical and market uncertainties based on Option Pricing Model, Real Option Theory and Option Space; ii) portfolio management and Stage Gate®1 method; iii) Monte Carlo simulation.

Jan 1, 2010

A coal mine located in southern West Virginia recently set a world record for daily low-seam coal production using a Cat automated longwall plow system. In a 24-hour period on April 10 and 11, 2014, the Pinnacle Mine longwall produced 32,411 t (35,724 st) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 1.42 m (56 in.) along the 298-m (980-ft) longwall face. The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 29,423 t (32,430 st) were mined in a 24-hour period. The record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013. ?Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,? said Chris Curfman, president of Caterpillar Global Mining Sales and Support Division. ?However, given the record production results attained by the rebuilt system at Pinnacle, it?s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.? Tom Bluth, president of Caterpillar Global Mining Products Division, said, ?Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ?

By Fabian Laumen, Sunny Schoone, Felix Leaman, ELISABETH CLAUSEN

The acoustic emission (AE) technology has a high potential for flow characterization in hydraulic transport processes. For instance, in deep-sea mining, there are applications where manganese nodules are transported from the bottom of the sea to the surface or a transport ship. Here, an AE-based flow characterization system plays an important role to avoid the transport of non-related objects. However, the structural materials for the components of this system must be carefully selected to ensure resistance against corrosion and a good AE signal transmission. Therefore, in this experimental study, we evaluated the AE attenuation behavior of four different materials that can be employed in marine environments due to their properties. The results were obtained using thin plates and they indicate which materials have the highest and lowest attenuations. Moreover, we provide insights regarding the different wave modes that propagate on the plates.

Mar 2, 2023

By Kenneth R. Miller

Surface mine equipment operators in the Campbell County region of Wyoming's Powder River Basin have found new ways of solving old problems. Technology, experience, competitive pressures and an increasing grasp of economies of scale have driven mine operators, equipment manufacturers and suppliers to specialization of applications. In economic terms, today's coal price of $4.95/t ($4.50/st) equates to $2.53/t ($2.30/st) in 1980 terms - an incomprehensible value at that time. This article describes some examples of change and adaptation made by Powder River Basin coal operators in overburden stripping equipment and techniques. It focuses on the evolution of the design and use draglines, shovels, trucks, scrapers and dozers.

Jan 1, 1998

By Robert G. Ditchburn

The Mariana arc is an ~1,400-km-long intraoceanic arc that marks the southern extension of the Izu-Bonin arc, and is host to 62 ?volcanic centers? of which at least 27 (21 submarine) are hydrothermally, or volcanically active. A surface ship cruise in early 2003 mapped the distribution of hydrothermal plumes emanating from these centers, followed by remotely operated vehicle (ROV) cruises with ROPOS in 2004 and Jason II in 2006. With the exception of one volcano (East Diamante), none of the vent sites visited by the ROVs were host to sulfide mineralization. Rather, they were characterized by high sulfidation mineral assemblages dominated by native sulfur. The sulfur was seen marking the vicinity of vent sites, or as sulfur ?chimneys? (e.g., NW Eifuku and Nikko), or more spectacularly as ?lakes? of molten sulfur, either occupying the summit crater of the volcano (e.g., Nikko), or perched on the flanks of the volcano, near the summit (e.g., Daikoku). Gas (H2S and CO2) was discharging through the molten sulfur. Evidence for these lakes to have either been substantially ?deeper? in their recent past (e.g., Nikko), or existing at other volcanoes (e.g., Seamount ?X?) is given by remnant ?pillars? of native sulfur that are reminiscent of rock pillars in lava lakes found along mid-ocean ridges.

Jan 1, 2008

Along with kyanite and sillimanite, andalusite forms part of the sillimanite industrial minerals trimorphous alumina-silicate group. Theoretically, andalusite contains about 60% A1203 and 40% Si02, with a Mohs hardness of 7 to 7.5 and a specific gravity of 3.0-3.2. Andalusite generally occurs in the contact metamorphic zones of schists and shales, constituting about 10% of the ground mass ore body. The 5- to 20mm- (0.2- to 0.8-in.-) long crystals are usually liberated through crushing and magnetic/heavy-media separation. Relatively minor occurrences of andalusite are found in Andalusia, Spain (where it was first identified), Portugal, the former Soviet Union, Ghana, South Korea, California and North Carolina. It also occurs in China, France and South Africa. The latter two represent nearly all the andalusite that is exported. Andalusite is an inert refractory raw material that does not require calcining before use. It involves an internal conversion to mullite after heating to 1400° to 1600° C (2552° to 2912° F). At higher temperatures of about 1800° C (3272° F), the mullite converts to corundum and liquid silica.

Jan 1, 1995

By Guy G. Jr. Granger

INTRODUCTION Due to the current depressed state of the mining industry, many mining companies have been forced to operate at less than maximum capacity. This paper will describe how the AMAX Henderson Molybdenum Mine and Mill near Empire and Parshall, Colorado respectively have utilized operations scheduling and budgeting to achieve production targets at minimum operating costs The AMAX Henderson Molybdenum Mine and Mill have been operating most recently at approximately sixty percent of maximum capacity. OPERATIONS SCHEDULING Production Targets. The production targets are tons, operating days, tons per opera- ting day, head grade, recovery, and pounds of molybdenum. One specific objective of operations scheduling is to meet the production target for pounds of molybdenum. Present market conditions dictate that production be adjusted to match sales of molybdenum. Over-production and creation of molybdenum inventories is unacceptable. In summary, the product ion target for pounds of molybdenum must be met, but not exceeded. Capacity. The AMAX Henderson Mill single stage open crushing circuit capacity is 48,000 dry short tons per day. The AMAX Henderson Mill single stage semi-autogenous primary grinding mill circuit capacity is 38,000 dry short tons per day. All other AMAX Henderson Mi 11 circuits such as rougher flotation, regrind, cleaner flotation, lead leach, filtering, drying and concentrate handling are sized to accommodate the 38,000 dry short tons per day and pro- ducts from same. The tailing delivery system is designed to accommodate tailing from a 38,000 dry short tons per day operation. Constraints. One mill production scheduling constraint is that the mill operating schedule must be the same as mine production, ore haulage and crushing. There is a total crushed ore stockpi1e storage capacity of 240,000 dry short tons. This breaks down to 60,000 dry short tons of crushed ore over the three reclaim pan feeders for each of the four primary grinding mill circuits. However, there is only approximately 10,000 dry short tons of live crushed ore available over the three reclaim pan feeders for each of the four primary grinding mill circuits. Dozers must be utilized to re- claim and push the other crushed ore. Primary grinding mill throughput is

Jan 1, 1986

By J. M. Barker

The concept of global-market access through transportation efficiency is a concept whose time has come. The basis of this approach is customer satisfaction—the higher the better. But beyond what seems almost too logical is the question of how to achieve this market access. All industrial mineral exporters face stiff competition. Factors include proximity of competitive industrial minerals and substitutes, pricing pressure, political and cultural differences, currency fluctuations, communication problems, trade finance restrictions, and transportation imbalances. The following discussion will focus on transportation activities in global competitiveness, but the producer with the larger offering of services will often make the sale, not necessarily the low-cost producer (Cook, 2002). Some key concepts for global-market access are “the market concept,” just-in-time delivery, quality retention, and global customer service.

Jan 1, 2003

By B. M. Flohr

Railroads are cost competitive with trucks for hauls greater than 500 miles - WRONG. Today I will tell you about many rail movements of less than 100 miles throughout the country. Rail is a short haul transportation alternative you must consider. Transportation today is the largest controllable cost in the total cost of production of goods. In fact it is the one cost area where aggressive management, using new tools, can achieve significant reductions. You can't control the price of metals in the world market, you can't control labor rates since they are tied to industry norms, and the price of raw materials are relatively insensitive to specific price reductions to your firm. Transportation is the one area where major savings are now being realized. Sample Movements First, I will give you several examples of short haul rail moves to make you a believer that they do exist. Then I will show you the reasons why railroads suddenly "like" short hauls.

Jan 1, 1986

"From April 22 to 28, the eyes of the tunneling and underground construction world will be on San Francisco, CA, as the world’s most influential underground construction industry leaders gather at the Moscone Center for the 2016 World Tunnel Congress.Recognized as the most important international annual meeting for the industry, the 2016 version comes to the United States for the first time in 20 years and will be hosted by the Underground Construction Association of SME (UCA of SME). The conference will be held in lieu of the UCA’s biennial North American Tunneling Conference and will bring the strengths and resources of the UCA of SME and the International Tunnelling and Underground Space Association (ITA). The result will be a conference with unmatched technical programming and a showcase of more than 200 exhibiting companies.A program committee led by Randy Essex of Mott MacDonald, Lonnie Jacobs of Frontier Kemper Constructors, Michael Mooney, of the Colorado School of Mines, Priscilla Nelson, of the Colorado School of Mines and Amanda Elioff of Parsons Brinkerhoff formed the program committee and worked for more than two years to build the program. The result is four technical sessions with five tracks in each session and 185 oral presentations.“One challenge was the sheer size of the group that would be assembled, perhaps 2,500 attendees or more, and the large number of abstracts we were likely to receive,” said Essex. “ We investigated extending the conference a fourth day, but that was not workable with the Moscone Center. We settled on having five concurrent technical tracks – something that has not been attempted in past NAT or RETC conferences to my knowledge. The next step was to develop suggested session titles that would span the breadth of subjects that would interest conference attendees as well as serve the conference theme.”"

Apr 1, 2016