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By Adeyemi Adesina, Subhabrata Mishra, Syed Mohammed Mustakim, Malaya Kumar Jena, Shaswat Kumar Das

Utilization of low-grade manganese ore adopting the carbothermic reduction roasting process is a proven method to produce high-grade manganese ore. To minimize industrial waste and protect the environment, gas cleaning plant sludge (GCPS), which is a solid waste from steel industries, was employed as a reductant to perform the reduction roasting process. The optimum conditions to carry out reduction roasting of the low-grade manganese ore were found to be: a roasting temperature of 950 °C, a residence time of 2 h, 40% GCPS as reductant, and magnetic separation at 5000 G for a manganese ore size of –10 mm. A lowgrade manganese ore comprising Mn grade 31.27% and Fe grade 19.78% having a Mn/Fe ratio of 1.58 containing a high silica content of 26.48% was used for the carbothermic reduction roasting having mineral phases of pyrolusite (MnO2) and hematite (Fe2O3) as found from XRD. The gangue minerals were separated during the magnetic separation, and the upgraded product was obtained, which reached a maximum value of TMn 49.5% with RMn 76.55% and TFe 62.19% with RFe 42.51%. In the study, activated charcoal (AC) was also taken as a reductant for comparative analysis; the experimental results revealed that GPCS performed better than that of the AC, showing potential to be used as a reductant in metallurgical industries. However, the resultedMn/Fe ratio was very low for the reduced sample; therefore, it can be used for smelting along with high-grade manganese ores as a feed.

Mar 5, 2021

By John H. Bassarear

Large scale equipment can reduce both capital and operating costs for concentrators. Large semiautogenous mills can be effectively utilized in big mills but they must be kept fully loaded to take advantage of their great potential. With varying hardness ores, controlling throughput is difficult and careful design must take this into consideration. A variable speed drive on large primary semi- autogenous mills can overcome this problem to a considerable degree. This paper provides a base case using standard accepted technology of two wound rotor single speed 4,476 kW (6,000 hp) motors to drive the primary SAG mills of a hypothetical 36,364 mtpd (40,000 stpd) typical porphyry copper mill. One other fixed speed drive will be described and five variable speed drive configurations will be reviewed. Capital costs for the entire grinding circuit, from crusher product to flotation feed, were developed for the base case and each of the alternatives. A technical evaluation comparing the advantages and disadvantages of each drive is presented.

Jan 1, 1985

By G. M. Ellis

This paper deals with some aspects of concrete construction in remote locations and/or cold climates. The writer's experience covers 25 years in construction in western and Central Canada. I will bring forth some pertinent observations and cost facts learned from this experience. Let us start by saying that there is nothing more important than preplanning the entire project. By this I mean the production of the engineering design, working drawings, soliciting of prices and ordering of all equipment and contractors work, the delivery of all equipment and all onsite work. All of this should be placed on a master schedule, preferably a C.P.M. We have been using C.P M. Scheduling for all of our work for 5 years and have found it in-valuable. This preliminary schedule will show initial items of work and target dates. After main equipment orders are placed and deliveries confirmed, the construction schedule can be revised to include manpower and construction equipment requirements. From this information the size of camp is determined. This, of course, must be ordered several months ahead. The manpower schedule can be broken into trades to tell us the number of men of each trade required at any time. This is important in helping to determine where the men must come from and whether or not any incentive is needed to get them. The schedule will also point out if it is impossible to get the project closed in before winter becomes too severe unless overtime is worked or the project is started in early spring. In most parts of Canada cold weather starts in October and lasts through April. A common term of reference has been to wait for the frost to come out of the ground before starting work in the spring. In some areas this can be as late as June. The construct-

Jan 1, 1971

By J. Harrison Daniel

More stringent dust standards, because of quartz in coal, have become a major compliance problem for the coal industry. Reducing quartz levels has become the major focus of the Bureau of Mines dust control research program. Results to date have identified hath the sources of quartz and prospective control technology. Control techniques are being developed for both room-and-pillar and longwall mining underground operations. Techniques include changes in face ventilation, mining cycle modifications, and better roof bolting dust control.

Jan 1, 1985

By E. Cho

Illinois No. 6 coals of IBC 101 and IBC 112 were treated in solution with sodium hypochlorite to remove their sulfur contents, especially organic sulfur. The lab experiments were conducted in two steps of leaching at room temperature and hydrolysis at 90oC. The removal of organic sulfur from IBC 101 was by 37.8% while that from IBC 112 was only 13.7% under their respective optimum conditions. This large difference in organic sulfur removal is considered to be due to difference in concentration of surface total acid group, 3.14 vs. 0.88 mmol/g of coal.

Jan 1, 2007

By Jerry F. Fountain

Variations in ore grade, mineralogy, and copper pricing structures over the life of the Inspiration mine have mandated many modifications to the treatment methods to maximize process economics. In the 1970's, copper prices generally declined, while inflation, wages, and interest rates increased. A metallurgical treatment route had to be developed for this continuing economic climate which would be capable of minimizing labor, energy, and capital cost requirements. After many years of development, the patented "Ferric Cure" process was introduced to satisfy these requirements. This dump leach process for treatment of mixed oxide/sulfide ore includes: strict mineralogical control of ore placed for leaching, controlled leach pad construction, solution saturation and curing of the pads with higher acid concentrations, and, finally, rinsing of the cured pads for removal of dissolved copper. Leach solutions, high in sulfuric acid during the cure application and low in sulfuric acid during the rinse, contain sufficient ferric iron to enhance the leaching of chalcocitic sulfide minerals.

Jan 1, 1983

By M. Kuchta, A. Newman

LKAB’s Kiruna Mine, located in northern Sweden, produces about 24 Mton of iron ore yearly using sublevel caving. For efficiency, the mine must deliver planned quantities of three ore products. We use mixed integer programming to schedule Kiruna’s operations, specifically, which production blocks should be mined, and when they should be mined to minimize deviations from planned production quantities while adhering to mining restrictions (e.g., sequencing). A new production block database and a well-formulated mixed integer programming model dramatically reduce the size of the original problem; in less than ten minutes we generate five-year schedules with time fidelity of months.

Jan 1, 2002

By Lancelot E. Kun

The high-rate floc blanket clarification process developed by the Anglo American Corporation of South Africa is capable of continuously clarifying gold and uranium pregnant solutions containing 200-2500 mg/L suspended solids to below 25 mg/L solids at an average rising velocity of 8 m/h at the low process cost of R0,001-0,002 per ton of liquid treated. Overall process cost savings are mainly due to increased polishing filtration cycle times.

Jan 1, 1984

By W. J. Atkinson

The first recorded discovery of diamonds in Australia was in 1851 in New South Wales. Subsequent prospecting has shown alluvial occurrences of diamond to be widespread through much of the Tasman fold belts of Eastern Australia. Production is estimated to be some 500,000 carats from several small alluvial fields. Despite extensive exploration, though, no primary rock source carrying significant diamond content has ever been confirmed in Eastern Australia. Conversely, diamond exploration of the older Western and Central Cratons of Australia during the past 30 years has discovered 12 fields containing 360 kimberlites, lamproites and lamprophyric volcanic pipes, dykes and other intrusives. Of those, 180 have been confirmed to be diamondiferous. Only one pipe, however, the 1200 Ma high-grade Argyle lamproite and associated nearby alluvials, has proved to be economically exploitable. Its current annual production is 40 million carats valued at about US$400 million. Production from the open pit will be sustainable until at least 2003.

Jan 1, 1995

By Robert P. Edwards, Brian C. Flintoff

Crushing plants (multiple stage) are an integral part of most conventional comminution circuits (ball mill, rod mill - ball mill). Although conventional circuitry is now the design exception, there are still many older, and some newer plants that include crushing in the process flowsheet. In most of these installations the operating objective is to maximize throughput at some minimum product size, in an effort to balance the comminution load between crushing and grinding. To achieve this goal, while avoiding production losses due to overloads, generally requires the use of automatic control strategies. This paper reviews the crushing plant control problem and describes several approaches that have been successfully implemented in different plants.

Jan 1, 1992

By D. Malhotra, K. Purdy, G. Ramadorai

INTRODUCTION Today, flotation is clearly the dominant mineral concentration method. Since it is a relatively selective process, it is used for almost all sulfide minerals. A recent U. S. Bureau of Mines study indicated that approximately 225 million metric tons of sulfide ore was processed in 67 plants in the United States in 1980 (USBM Staff, 1981). There were over 100 plants processing copper ores in the world (Bassarear, 1985). Sulfide ores containing lead, zinc, copper, molybdenum, precious metals, cobalt, nickel, and iron are generally separated and concentrated by flotation. This chapter briefly reviews the plant practice related to the recovery of the above-mentioned sulfide minerals with emphasis on chemical reagents used for the production of marketable-grade products. PROCESSING OF SULFIDE ORES It is beyond the scope of this chapter to review the milling data for operating plants which have been extensively covered in literature (Tveter and McQuiston, 1962; Rausch and Mariacher, 1970; Weiss, 1985; Crozier, 1979). However, the following generalizations can be made regarding the processing of sulfide ores: 1. The primary grind is targeted to produce as coarse a product as necessary to provide an economic degree of liberation. 2. The concentration process, generally flotation, is designed to produce a concentrate consisting predominantly of valuable minerals and a middling fraction which may require further grinding to produce an optimum release of minerals. 3. The chemical reagent suite (collectors, frothers, etc.) for the separation of sulfide minerals from gangue minerals is generally complex. Total reagents used in the flotation process can be as high as six to eight, as is the case for lead and molybdenite separation from complex sulfide ores. 4. Chemical reagents are generally expensive because of the high selectivity for sulfide minerals. The process flowsheet is dependent on several factors, including ore grade and mineralogical composition. Generic process flowsheets for processing different sulfide ores have been developed for discussion in this chapter. However, there appears to be a consistent relationship between the reagent combination choice and the mineralogical composition of the ore (Tveter and McQuiston, 1962). These are covered in detail in the following sections. LEAD AND ZINC Galena (PbS) and sphalerite (ZnS), which commonly occur together, are the only minerals of lead and zinc, respectively, in most primary deposits. Feed ore grades are typically 1 to 5 percent Pb and 1 to 10 percent Zn. Very often economic quantities of copper and precious metals, silver and gold, also occur with these base metals.

Jan 1, 1986

By Tor L. Brekke, Alberto Marulanda P.

The paper describes hazardous water inflows during construction that have taken place over the last three years in tunnels in Colombia. The projects involved are the Chivor II Hydroelectric Power Project (penstock tunnel), and the Chingaza Water Project (two tunnels). In all cases, loss of face control led to significant loss of ground; in one case some 70,000 m3 of slide material was involved, much of which came out through the portal situated 1.6 km from the face. Emphasis is given to: (a) the geologic setting, (b) the remedial measures taken, and (c) the main efforts that can be made to prevent hazardous conditions from developing.

Jan 1, 1981

By M. E. Smith

Waste rock dumps, tailings impoundments and spent leach heaps are common features at mine sites. Many of these waste disposal facilities contain sulfide-rich minerals, which generate acid mine drainage (AMD) when they oxidize. Control of AMD can be achieved by removing one or more of the three essential components in the acid-generating process (sulfides, air, or water). One AMD prevention measure is to cap the waste with an engineered cover system to minimize the infiltration of water and diffusion of air into the system. Possible cover designs include: ? Earthen ?store-and-release? covers (also known as evapotranspiration (ET) or water balance covers), including capillary barriers. These covers require climate conditions where there is both modest to little rainfall and significantly greater evapotranspiration than precipitation, both annually and seasonally. ? Low-permeability compacted clay liners (CCLs) employing fine-grained soils typically compacted at wet of optimum water content. ? Geosynthetic composite covers, comprised of a geomembrane liner placed over and in direct contact with either a CCL or a geosynthetic clay liner (GCL). These systems have been commonly used for base liners for leach pads as well as covers and base liners at municipal solid waste (MSW) landfills in the US for more than 20 years. Comparisons of these different cover systems, both in terms of performance and cost, are presented later in this paper. First, however, a review of the typical mine closure approaches, and the possible rationale behind them, is warranted.

Feb 27, 2013

By Ari Glazer

"Every year the tunneling business is expanding and collaboration with the International Society of City and Regional Planners (ISOCARP) for the future design of cities and urban communities is in the making. During the last half of this century, billions of people migrated to cities, and it is estimated that by 2030 almost five billion people worldwide will reside in urban communities. Hence, “Underground development will be an important tool in reshaping our urban areas to meet the challenges of the future without destroying their heritage or worsening their surface environment” (Esaki, 2005). In 2013, the Organization for Economic Co-operation and Development (OECD) estimated life expectancy to be around 80 years, meaning that in less than a decade we will need to bury billions of people in cities and urban communities, while trying to retain the deceased’s beliefs and customs. Religion plays a major role in our lives, and many people worldwide still decline to cremate their body after their death; therefore, cemeteries are essential for city inhabitants. Rites and traditions usually call for burials to be near the place of residence, which allows the remaining family members and friends to visit the grave frequently, at least in the first years. This is a challenge that urban designers and architects must confront while trying to solve the problems of future urbanization. In recent years, population growth, the rising cost of land and the extensive preservation of green areas have made cemeteries a burden and a nuisance, particularly for large cities and communities. Many graveyards that were once on the city's outskirts have become lifeless islands in populated areas (Fig. 1), rarely visited by the second and later generations. Cities worldwide face the challenge of allocating less land to maintain current burial practices. In response, some cities have begun to bury their dead at a great distance from the community; others have started to stacked burials, one on top of the other, while still others are constructing buildings and even skyscrapers for the practice of burial (Fig. 2)."

Jan 1, 2016

By J. E. Stephens

US Borax began exploration in southeast Alaska in the summer of 1971 with a staff of two, Barry Watson and Jackie Stephens, based in Spokane, WA. After several years of prospect examinations in the islands west of Ketchikan, AK, and with the able assistance of prospector-pilot Kenny Eichner, Jackie Stephens proposed and organized a boat-based, helicopter-supported, stream sediment sampling program to explore the western contact of the Coast Range intrusive complex on the mainland. The rationale for this included: the extension of known mineral trends from Canada into southeastern Alaska along favorable geologic zones; the western contact area of the Coast Range intrusives with metasediments and metavolcanics was a favorable target for metals exploration as shown by numerous small prospects. Knowledge gained from mineral exploration of the island areas indicated that they were well mineralized, but already well explored, and that the known mineral potential was probably present in subeconomic quantities (Brooks, et al.). Publications of the US Bureau of Mines and other scientific agencies were gathered and every prospect within the southem southeastern Alaska area was plotted. This in itself lent a tremendous amount of knowledge to the total exploration program. US Borax's McLean Arm copper property on Prince of Wales Island was drilled and dropped while this compilation of data was proceeding. We found that many companies had followed one another around the island areas, but little or no exploration had been done on the west side of the Coast Range, and that many explorationists flatly stated that the west side of the Coast Range was barren of mineralization. In summary, although some of the shoreline and near shoreline areas of the mainland had been explored, no organized boat-helicopter exploration program had been done along the favorable western zone of the Coast Range Intrusive complex. We decided to use a boat as a floating hotel for the crews that were to be helicoptered into the back country from tidewater for our initial stream-sediment sampling program.

Jan 1, 1991

By T. Patten

A method for stabilizing mercury containing waste for landfill disposal would be a very cost effective solution for industry. A mercury polythiocarbonate material which is made via a metallurgical process passes a traditional TCLP for mercury. The mercury polythiocarbonate material was subjected to a more thorough evaluation, the Integrated Leaching procedures as described in Kossan (1) and Sanchez (2)The procedure involves leaching the mercury polythiocarbonate material at varying pH and sample size to liquid. The procedure had to be adapted for small sample sizes and finely divided materials due to the product characteristics and available material. The leachates were evaluated and found to be stable within common environmental pH values. The performance details on how Inter-Mountain Labs met the leaching requirements of the procedures and the analysis of mercury are presented.

Jan 1, 2012

By Steve Hansen

Heap leach mining has long been an economical method for mining oxide copper ore, and with the U.S. Bureau of Mines' discovery of a way to economically strip gold and silver from carbon, it has become the standard in the gold and silver indus­try as well. Sulfide leach in copper recovery has always been a byproduct of oxide leach mining, although the methods and recovery rates have increased with technology. SX-EW has kindled a new interest in large deposits and dormant dumps of low grade sul­fide ore. Gold ore bio-oxidation was developed in the 1980's, but not tried on a large scale until US Gold built the Tonkin Springs Mine. This mine was dedicated to the large scale production of low grade sulfide ore that could be recovered through the newly discovered bio-oxidation method. On a small scale the method worked, but as time went on, problems with the process were costly and recovery was poor. US Gold did not have the finan­cial backing to perfect the process, and the mine was closed in 1990. Since that time, Newmont Gold Company has taken the lead and has dedicated a lot of resources to the perfection and implementation of this method. Some small mines have discov­ered that if they can use this technology they may be able to dou­ble and triple current ore reserves, because they will be able to mine deposits previously considered not to be economical.

Jan 1, 1998

By P. K. Das, S. K. Singh, C. C. Chang, E. C. Wang, R. B. Roberts

As part of the New York City’s redevelopment of the far west side of mid-town Manhattan, this project will add 1.5 miles of twin bored tunnel to No. 7 Subway Line. The proposed alignment extending from the Times Square Station west beneath 41stStreet turning south under Eleventh Avenue and terminating at 25th Street will include two new stations. The tunnels and station caverns will be primarily constructed in the Manhattan Schist, and will pass in close proximity to several major overly ingstructures. This paper discusses the lithology and structural discontinuities of rockmass along the project alignment, tunnel and cavern rock loading, groundwater hydrology, groundwater quality, groundwater treatment and sustainable design.

Jan 1, 2005

By S. Solar, G. Tiess, K. Nielsen, H. Wagner

The paper summarises the results of a recent study of minerals planning policies of the Member States of the EU. The study has shown that contrary to the public opinion the production of industrial minerals and construction minerals is significant the former accounting for about 20 percent of global production, the latter amounting to about 3 billion tonnes per annum. In contrast the importance of metal ores has diminished although metal production in some European countries can still be significant. The study revealed that very few Member States have clearly defined mineral policies. Common to most mineral policies is the emphasis on reducing minerals consumption and recycling whereas the important aspect protecting access to minerals resources is not adequately addressed by most policies. Access to mineral deposits is regulated in most Member States by land use legislation and administration. Information on mineral deposits in land use planning data bases tends to be scarce. This together with the absence of formal mineral policies places minerals at a disadvantage in land use decision making. The emergence in the recent past of environmental legislation and in particular environmental impact assessments has had a crucial effect on the duration of the authorization process for new mineral projects. Examples are given how minerals planning is handled in some of the Member States.

Jan 1, 2005

I met Austin Taylor in Vancouver on my way home from my first Pioneer examination. He asked me to examine the unsuccessful old Lorne mine, adjoining and west of the Pioneer. I had no idea that this meeting would lead to one of the outstanding successes and pleasant associations of my career. I knew nothing of Taylor, except that Gen. McRae and associates said that he had been engaged in lumbering and was interested in an oil and gasoline marketing company called Home Oil. But even if the Lorne examination would be only a small one, in the depths of the Depression in 1931, I was glad to have a chance to look at another gold property, so I agreed to visit the Lorne early in August. The start of the trip was not auspicious. I had been working hard on an unproductive study, and was greatly worried by my father's hopeless illness with tuberculosis. To get a little rest on my way north I had arranged to go from Seattle to Vancouver on the night boat that connected with my train. To my surprise, Bill Boultbee, an associate of Taylor, met me at the train in Seattle at 9:30. He said he would drive me to Vancouver, arriving at one In the morning. I was so tired that I begged off and let him take the drive alone Boultbee was most understanding and friendly, but I knew how I would have felt if I had been kind enough to take the long drive to help a stranger and then had been forced to make the return midnight drive alone. I was lucky they did not call off the examination at once. I got a good sleep on the Vancouver boat and Austin Taylor met me at the Hotel Vancouver for breakfast. After a brief talk he took me to the small steamer that made the 4-hr sail up Howe Sound to the village of Squamish. This was the end of the Province-owned Pacific Great Eastern Railway that was eventually to be a shortcut from Vancouver to the Canadian National main line at Prince George. Because

Jan 1, 1976