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By E. Costa Silva

Among the methods of mineral processing, gravity concentration methods are, probably, those which have lower costs, higher capacities and lower operational complexity. In order to be really effective, these methods require a feed size distribution in which the particles are liberated. Further, there must be a significant difference (usually higher than 1-1.5) among the real densities of the particles. However, in most cases, the traditional gravity concentrators (jigs, shaking tables, spirals and dense medium hydrocyclones) lose efficiency (sharpness of cut and recovery) when the mean diameter of particles are lower than 0.05mm and the difference among densities are smaller than 1. Most gravity concentrators developed in the last 20 years are based on the use of centrifugal forces that create large "apparent gravitational gradient" seeking to overcome the limitations of particles size distribution. This paper presents the experience of the CVRD Research Center in evaluation and development of new process based on using this new generation of gravity concentrators.

Jan 1, 1999

An incremental analysis based stope design optimization method was developed at Exodus, an underground project located 30 miles north of Carlin, Nevada. Traditional underground stope design methods, by manually drawing stope shapes, are typically very time-consuming and lacking of consistency and accuracy. For quick reserve calculation and economic analysis, a new method named '3D Incremental Analysis based Stope Optimization' was created for mine wide stope designs at Exodus. With this unique but practical method, multiple options of mine designs were completed within a short period time, which allowed us to select the optimal cutoff grade and best stope design option for the project.

Jan 1, 2012

By C. A. Kumke

The Korean crisis and the cessation of Russian manganese-ore shipments to the United States in 1950 reemphasized the almost total dependence of the domestic steel industry on foreign supplies for metallurgical-grade manganese ore. In this emergency, Congress authorized the Bureau of Mines to undertake experimental mine and process development work on the known large reserves of low-grade manganese ore in the Artillery Mountains region in Mohave County, Ariz. The objective of the work was to obtain the basic mining and metallurgical data needed to make specific plans for initiating exploitation of the deposits within 3 years if high-grade foreign ore could not be obtained during the emergency. The manganese deposits of the Artillery Mountains region are in an area of about 25 square miles on the north side of the Bill Williams River in southern Mohave County. Lasky, of the Federal Geological Survey, has estimated reserves at 175 million tons of manganiferous material assaying 3.5 to 4 percent Mn. Although the man¬ganese occurs in various Tertiary and Quaternary formations as both bedded and fissure vein deposits, the more important syngenetic deposits are found in upper and lower manganiferous zones in the sedimentary beds of playa and alluvial fan origin that constitute the Chapin Wash formation.

Jan 1, 1957

By John Parianos

"Seafloor mining provides significant potential economic benefits for many Pacific nations that may be "land poor" but "coastline rich," meaning they have the potential to utilize and profit from the mineral wealth within their Exclusive Economic Zones that extend 200 nautical miles (360 km) out from their coastlines. The Independent State of Papua New Guinea (the State) recognizes this tremendous opportunity and is taking a leadership role in this emerging industry by becoming a 15% partner in Solwara 1 (with an option to increase their investment to 30%).The Solwara 1 Project has been gaining momentum since Nautilus Minerals and the State signed an Agreement on April 24. This new agreement with the State in which they have staked a minimum 15% interest as a meaningful partner, underscores the State’s continued and widespread support for the Project. Signing of this Agreement was a historical occasion and a milestone achievement for Nautilus Minerals and the people of PNG.The machinery being built for the Solwara 1 Project is taking shape. The Seafloor Production Tools are now over 90 percent complete. Assembly of the biggest tool, the Bulk Cutter, was completed in April this year and assembly work on the Collecting Machine and the Auxiliary Cutter commenced in May and June this year respectively. The Riser and Lifting system, which will be used to transfer the mined material from the seafloor to the surface within an enclosed system, is over 50 percent complete. The critical path for the Solwara Project is to secure a suitable vessel arrangement. Nautilus aims to have this completed by the end of this year."

Sep 1, 2014

By Lars G. Olavson

A prototype roof bolt which can be remotely placed by pumping has been developed by the Bureau of Mines. It is known as the "Pumpable Bolt". With the objective of field testing the effectiveness of the pumpable Bolt roof support system a mining machine was developed capable of installing Pumpable Bolts in the normal production cycle of a typical underground coal mine. The machine was built and the pumpable Bolt concept tested and evaluated as a total system in shop and mine tests. The machine was operated in the mining cycle of two mines and pumpable Bolts were installed at both mine sites.

Jan 1, 1976

By F. Heivilin

If the past is the key to the future, we will have ?tough? times maintaining Industrial Mineral reserves we have and proving new reserves around our plants and in new locations. The tough times will come from resources being more difficult to find, more hoops to go thru to make them Proven or Probable reserves. As always, Industrial Minerals require competitive quality, location, and costs. Since in most cases the market has suppliers, you will have to take away customers from their present supplier. This may take years or not happen even with lower cost higher quality raw materials. To determine the finished cost for a new deposit you need to design, determine capital costs, and operating costs for a new plant . Stripping, mining, hauling, processing, and transportation costs are part of the equation. After satisfying that your costs are in line you will need to do production tests to make sure the process works on the ore. You may want to complete permitting before purchasing the property. If you are new in the business you will have to prove you can deliver the right quality, the right quantity, on time consistently year after year at lower cost to take away a customer. Without being in the market this will be hard. The cut off grades to enter a market may be much lower than sale indicates because a competitor often lowers the price to keep you out of the market. We have many more items to check before the new deposits can be put on reserves. Our old reserves will require drilling to check for new products and prove that they do not contain items that would make them unusable for our product line or cause permitting problems. Archeological checks, wetlands, more water discharge testing, county zoning, and endangered species are among many items that have been added to mine permits. There will be more. A 4-6 page mining permit becomes 30-300 pages and consists of 5-15 permits, any of which might be a fatal stumbling block. It is not guaranteed that we can mine what we have on reserves. We may fight and lose. Oil-Dri?s loss in Reno and LaPort?s in England are examples where permitting failed. The NOx, sulfur, and carbon problems are just starting. Dioxin is in the background requiring monitoring on food products to Europe. What other anions, cations, endangered species, and land types are going to be problems in the future are guesses now. What new products are we going to have to test for and cause out of balance reserves? If there are none we probably won?t be here. We are competing for land use with ?Endangered Species?, wetlands, farming, forestry, cities, roads, and hunting. We?ve mined the best quality, low overburden, easiest to mine and process raw materials. The price of land and taxes are increasing. Old royalties are 2-3 times the present acre value instead of 8-10 times the property value when leased. Land taxes are up. It was and is best that we get the land in Fee Simple Title. This isn?t always possible. However, plants are closing and people have overlooked, made mistakes in drilling or interpretation of deposits. These may be opportunities. China is eating up high quality ?Industrial Minerals ?which have caused prices to rise. We may need to change our cutoffs? in terms of smaller pit sizes and higher overburden ratios. This is money in the bank. Overburden ratios and other items increasing cutoff costs need to be rethought. Suddenly doubling cutoff ratios for overburden and decreasing pit sizes are good alternatives to looking elsewhere where we might not be able to mine for a number of reasons. The higher prices make them competitive, especially when a competitor goes out of business. However, our low overburden ratios and short hauls around our plants are not safe from new roads, condemnation by county or city governments (N. J.), zoning changes (Reno, FL., CA, and environmental regulation changes (Buffers GA, MS). New roads ?Interstates? can take reserves, increase hauling distances and reduce tons per load. Let?s combine the Refractories, fullers earth, and bentonite industries and use the last 40 years as a guide to the future looking for problems and opportunities. Some or most of the following will apply to other minerals. WHERE DO WE LOOK? First, on our own properties, those next to our properties and on properties near our competitor?s plants. Where the profit margin has increased, the distance from the plant and thickness of overburden we can use is increased. The thickness of clay is decreased. For new locations we pick the ideal location and look at deposits and closed or open operations in ever increasing distances away from that location. We need to be aware of: 1. Increased transportation costs a. Access to Roads -Backhauls b. Haul with doubles and triples c. Railroads - Loading on sidings - Ability to get switches - Cars/backhauls versus rates 2. Cost of building a new plant 3. Cost of infrastructure 4. Cost of repair or new equipment when purchasing an operating or shutdown plant. 5. Local, state, and federal mine and environmental permitting. When exploring around an established operation expect that property acquisition, drilling, mining, stripping, and hauling costs will be greater due to them having second, third, or even fourth the pick of the deposits. I found this in New Jersey looking for refractories and around Quincy, Florida looking for attapulgite. You may be able to get some better properties because the operating company has angered some land owners, their drillers missed the clay, or the property wasn?t available when they were actively exploring for reserves. You may have some product lines your

Jan 1, 2009

By F. Hassani, K. Moozar, J. Ouellet, P. Gauthier

"This paper describes a sudden spill of waste rock used for backfilling from a waste pass at an underground mine in Canada, thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in the future. The authors from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied, appropriate measurements were taken and samples of the waste material were collected for further testing and analysis.The field visit and the interview of the witnesses allowed the detailed documentation of the events. The sequence of events related to the incident, along with the experimental results obtained in the course of the investigation, are presented. The waste material was characterized in the laboratory with regard to its behaviour in the presence of water. This information is discussed and the failure mechanism involved in the accident is identified. Finally, the full recommendations as well as the immediate operational measures implemented by the mine to prevent the future occurrence of such events are presented and discussed."

Jan 1, 2004

By Braam Blom

PK2 Ventilation shaft is part of Paardekraal No 2 twin shaft system that is being developed to replace depleting Merensky reef production at Paardekraal shaft complex. The sinking team at this shaft faced considerable challenge of improving the total sinking cycle in order to be able to deliver the fully equipped shaft on time and on schedule. The cladding support cycle was identified as the tedious and time consuming activity in the overall shaft sinking operation. Reduction in the time required for handling and setting up the support installation equipment, and the time required for subsequent installation of the necessary support has a direct impact on the overall cycle time, and consequently the overall productivity and efficiency of the sinking operation. This reduction in support cycle was achieved by making use of machine carousel. The objective of this paper is to describe the support methodology that was used during the ventilation shaft sinking and the use of the machine carousel to reduce the cladding support cycle. The machine carousel replaces the traditional use of machine kibble in conventional vertical shaft sinking and has been designed specifically for installation of sidewall support at the shaft bottom during the sinking process.

Jan 1, 2009

The Santa Rita mine is located in north eastern part of Bahia in Brazil and is owned and operated by Mirabela Mineração do Brasil Ltda. Typical SABC circuit was designed as the preferred option for the 4.0 mtpa (500tph) to produce a P80 of 125um for flotation. Although the SAG was originally designed to operate with conventional radial pulp lifters, later it was fitted with Outotec?s Turbo Pulp Lifters ? TPL (Latchireddi, 2005). The milling circuit commenced commissioning on the 24th of October 2009 and the milling circuit achieved the nameplate capacity within days. with small and relatively simple measures to rectify. Since commissioning, the SAG mill has been working in fully autogenous grinding (FAG) mode with no balls (in contrast to the estimated 10% ball charge) and has been consistently treated up to 650tph. This paper examines the comminution design process, the operating philosophies, start-up experiences, post commissioning optimization and future development works. An evaluation of mill performance relative to the design criteria for the project life to date is also included.

Jan 1, 2012

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By William Gleason

The mining industry is at a crossroads. Currently, there is an estimated $25 billion worth of projects around the world that have been stopped as the consequence of a dispute or disagreement with their communities, the government or some other stakeholder. Anglo American chief executive officer Mark Cutifani is one who sees the mining industry in need of change and on Dec. 12, he gave the keynote address for the launch the Kellogg Innovation Network?s Mining Company of the Future Initiative?s Development Partner Framework (DPF). The launch was held at the Ford Foundation building in New York City. The DPF seeks to inspire and support the mining industry to adopt a new way of thinking and a new approach to how it secures, nurtures and revitalizes its social license to operate. Working with a diverse group of people from faith-based organizations, nongovernmental organizations (NGO) and other stakeholders, Cutifani often had the rather uncomfortable position of representing the mining industry in a room full of people who are far from the industry?s biggest fans.

By Robert T. MacMillan

An essentially chemical technique has been developed on a small scale for the efficient utilization of certain domestic titaniferous iron ores. Three main steps are involved: (1) Sintering the ore at 1,050° C. with carbon and soda ash to reduce the iron to metal powder, retaining the titania in the slag, (2) separating the powdered iron from the slag, after wet grinding, by magnetic or gravity methods, and (3) sulfuric-acid decomposition of the titania fraction to produce pigment and certain byproducts. The technique was first applied to the tailings from the Bureau of Mines bauxite-concentrating plant at Bauxite, Ark. A good grade of powdered iron was produced from this material. Subsequently, the work was diverted to the study of the titaniferous magnetite from the MacIntyre Mine at Tahawus, N.Y., because of the potentially higher recoveries of iron, titanium and vanadium. Ninety percent of the iron in this ore has been recovered as an iron powder analyzing 90 percent metallic iron and containing 2 to 3 percent TiO2. The remaining titania was found in the slag and was recovered as pigment-grade TiO2 by application of a suitable technique. The vanadium was distributed between the TiO2 fraction and the alkaline liquor resulting from the wet-grinding and magnetic-separation operations, with only a minor proportion retained by the metallic iron.

Jan 1, 1950

By Peter Bourke, Marc van Olst, Seppo Ronkainen, Natalie Brown

"Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technician’s job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always a lot of other tasks to do.A considerable amount of work has thus been done to develop a “system” that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterTM instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability.Three FrothMasterTM units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:To control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other.Control of the concentrate grade (%Copper) from the first rougher.Reduction in the frother consumption in the rougher circuit by monitoring the froth speed.A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions:Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint.Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time with an OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore."

Jan 1, 2001

By D. K. Ingram, P. Jurovcik

The National Institute for Occupational Safety and Health (NIOSH) identified hearing loss as the most common job-related disease in the United States in its 1996 National Occupational Research Agenda. Previous studies by NIOSH have shown that operators of surface drill rigs without cabs are commonly exposed to A-weighted sound levels exceeding 90 dB. During hammer-drilling, A-weighted sound levels exceeding 100 dB were recorded at the operator station. NIOSH collaborated with a local drilling company to design and install a partial cab between the operator and the drill steel in an effort to reduce the sound level at the operator station. Sound level measurements in the field show the partial cab reduces the A-weighted sound level by 5 to 9 dB at the operator’s left ear and 2 to 5 dB at the operator’s right ear while hammer-drilling. This paper briefly discusses the preliminary design of a cab and the testing of materials for construction of the prototype. An explanation of the ideas behind the prototype design and fabrication are covered. Finally, the field test method and results are discussed in detail.1

By Mark Fennel

The present paper describes the operation and application of the QEMSCANTM automated applied mineralogy technology and how it is been utilized for long range planning by characterizing and optimizing the primary sulfide reserve while providing operational support of the ongoing secondary sulfide leaching operation at the Cerro Verde Mining Complex in Arequipa, Perú.

Sep 12, 2005

By D. Settles, R. Rose, P. L. Dunn

"A new mineral sands operation is being developed in Georgia by Southern Ionics, Inc. (SII). Prevailing mineralogy and certain design constraints required detailed testing and circuit analysis to create a robust separation processes. The floating wet concentrator plant (WCP) and mineral separation plant (MSP) flow sheets were designed based on historical testing information and recent SII test campaigns on various composite feed samples. The flow sheets were finalized through rigorous process and orebody sequence modeling.The process uses traditional physical separation equipment; however a new MT spiral, the MG12, was selected for use on board the WCP for roughing duty. The MG12 spiral is a two-stage, twelve-turn spiral that has been proven to achieve very high recoveries of heavy minerals. The floating plant includes feed desliming operations, a central MT surge bin for optimum spiral circuit feed control and ancillary operations for concentrate and tailings handling. Scrubbed heavy mineral concentrate (HMC) is then transported to the MSP for concentration of the titanium and zirconium bearing mineral fractions.The testing, flowsheet development, and plant design will be described and explained, and a brief summary of the current project status will be given.IntroductionSouthern Ionics Inc. (SII) is a privately held chemical manufacturing company, founded in 1980 by Milton Sundbeck. SII focuses primarily on the sale of specialty and intermediate inorganic chemicals. Core markets include cement and refinery catalysts, molecular sieves, zeolites, pulp and paper, pharmaceuticals, TiO2 and water treatment. SII is built on the four cornerstones of service, quality, technology and delivery with all SII facilities ISO certified and key products used in potable water treatment certified to NSF standards. SII owns and operates its own transportation fleet and is focused on being a low cost producer, committed to safety and the environment."

Jan 1, 2015

By Leonard Weixler, Peter Halbach, Michael Jarowinsky, Johannes Post

Germany as an industrial nation is highly dependent on the import of mineral or metal resources. Sources which have not been considered until now are the marine mineral resources (MMR), which in recent times are enjoying more and more increasing interests and which might provide in the future a considerable contribution to the supply security on metal resources not only for the industrial countries. Backed up by the German government’s "National Masterplan Maritime Technologies" (NMMT) and corresponding industrial R&D-activities, the idea and the advantages of deep-sea mining is gaining more and more interests and supporters with respect to industrial and political considerations on strategic raw material resources as well as on the development of deep-sea mining technologies. The NMMT aims to initiate growth and increase the competitiveness of the German maritime industry on international markets and covers about 10 different marine and ocean technology sectors including deep-sea mining.

Sep 1, 2014

By J S. Dunlop

At its most basic level, minerals project management may be broken down into a series of logical chronological phases, described in this paper as: exploration, discovery; scoping and pre-feasibility; feasibility and approval; project financing and commissioning; operation; expansion and closure. Each phase has its own peculiarities and challenges, any one of which can potentially upset the forward progress of a minerals project.Reference is made to each of these project phases based on the authorÆs many years of first-hand experience, in an attempt to identify issues within the project management spectrum where additional caution may be warranted. Left un-addressed, these issues can cause undue delays in the project timeline, ultimately delaying approval at significant project cost.Finally, reference is made to the Mine ManagerÆs Handbook recently published by the AusIMM which is an excellent project management resource, considered to be very relevant for minerals treatment plant managers, whether the context be constructing, operating, expanding or shutting down.CITATION:Dunlop, J S, 2013. Mineral project management - A perspective from four decades in the industry, in Proceedings MetPlant 2013 , pp 13-27 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By H. B. Brunot, L. C. IlsLey, E. J. Gleim

"INTRODUCTION To supply inspectors, safety engineers, and others with detailed information as to the safety features of the various electrically operated machines that have been approved as permissible by the Bureau of Mines, three bulletins and five reports of investigations have been published dealing with the various classes of approved machines:Bull. 313, Permissible Storage-Battery Locomotives and Power Trucks.Bull, 343, Permissible Coal-Handling Equipment Approved from January 1926 to December 1930, inclusive.Bull. 382, Permissible Coal-Cutting Equipment Approved Prior to July 1, 1932.Rep. of Investigations 3309, Permissible Electrically Operated. Air Compressors.Rep. of Investigations 3326, Permissible Electrically Operated Room Hoists.Rep. of Investigations 3345, Permissible Electrically Operated Rock-Dust Distributors.Rep. of Investigations 3363, Permissible Electrically Operated Hand-Held Coal Drills.Rep. of Investigations 3391, Permissible Electrically Operated Post Drills and Drilling Machines.The present paper gives similar information relative to the mine pumps approved before October 1, 1939."

Mar 1, 1940

By H. W. Earnest

This report covers the results of a two-phase study to determine the feasibility of underground disposal of retorted oil shale. Two mining methods, chamber and pillar mining and sublevel stoping, were specified for backfilling. Phase I of the study covered the evaluation of hydraulic, mechanical, and pneumatic transport and stowing systems, individually and in various combinations, and the selection of the most feasible methods. Conveyor transport and stowing and a combination conveyor transport and stowing with pneumatic topfilling were selected for detailed study of phase II. Phase II activities included detailed engineering analysis and design of the selected systems, an engineering economic analysis, and a cost comparison with total surface disposal of retorted oil shale. An extensive literature search was conducted and the bibliography is included in the report. Research done under Contract No. J0265052 by the Cleveland-Cliffs Iron Co. Available for reference at Bureau of Mines facilities in Denver, Colo., Twin Cities, Minn., Bruceton and Pittsburgh, Pa., and Spokane, Wash.; U.S. Department of Energy facilities in Carbondale, Ill., and Morgantown, W. Va.; National Mine Health and Safety Academy, Beckley, W. Va.; and National Library of Natural Resources, U.S. Department of the Interior, Washington, D.C. Order ONLY from NTIS:

Jan 1, 1978