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By Shouci Lu, Keji Sun, Dianzuo Wang, Yiqun Li, Chuang Jin

The dephosphorization of iron ore and reduction in Fe loss in process are currently the foremost technological challenges facing the mineral industry of Meishan Iron Ore. These problems can be resolved to a greater extent by an apatite flotation process which depends on selective flotation reagents. The primary objective of this research work is to develop new type of flotation collectors for dephosphorization of weak magnetic iron ore. Detailed discussion is given on the influence of collector dosage, pH, dispersants and pulp temperature on the flotability of apatite, siderite and hematite using the collectors of Oleyl sarcosinate(OSS), Alkyl polyoxyethylene ether phosphate (AEP) and the mixtures of OSS and AEP A key feature of the flotation was the use of the mixtures of OSS and AEP as a selective collector for phosphate. The effects of chemicals and operational variables on the phosphorus flotation from the weak magnetic iron ores have been investigated. The test results shows that floating the phosphorus minerals with new type collectors can reduce the phosphorous content in the flotation concentrate to an acceptable level of less than 0.20% P with increased Fe recovery.

Jan 1, 2002

Mine managers need better information to locate new opportunities and then to assess the effect of their decisions. We are developing the Intelligent Decision Support System (IDSS) and its two major modules, the Pattern Recognition System (PRS) and the Knowledge Representation Subsystem (KRS) to automatically provide the information from monitoring system sensors. This paper focuses on the KRS Algorithms that extract key information from lists of time study type event sequences. Because a static system cannot operate effectively in a dynamic mining environment, we are prototyping an index based technique that allows the system to adapt itself to this dynamic environment.

Jan 1, 1990

By John W. White

Anthracite mine refuse, or culm dump material as it is sometimes called, is the waste material resulting from the sizing and cleaning of run-of-mine deep and strip-mined anthracite coal. It may also contain mine rock, carbonaceous shale, pyrite, and other debris from mining operations. This material is generally stored in piles or banks, some of which are over 100 years old. Many of the older banks contain a considerable amount of good coal, particularly in the finer size ranges, since these sizes did not have any particular economic value in the early days of anthracite mining. Today, the refuse material from a cleaning operation must be piled in an orderly fashion and in such a way as to minimize the tendency to ignite. There are well over 400 of these banks in the anthracite region containing over 1100 million tons of refuse located in the north-eastern part of Pennsylvania. The banks range in size from a few thousand tons of material up to as much as 13 million tons. Most of

Jan 1, 1972

By Ven Mercade

The flotation of calcite has been studied by many investigators, especially in terms of type of collector; pH; and metal ions that activate and, more importantly, depress the flotation of calcite (1)(2). Research was extended to the investigation of the effect of polyvalent metal salts and sodium silicate using these materials added separately or in mixtures (3)(4)(5)(6). Flotation of calcite was also studied with respect to its function as a carrier in the beneficiation of kaolin clays by Ultraflotation (7) (8) (9). The carrier used in Engelhard Minerals & Chemicals Corporation's industrial Ultraflotation operation is calcite. This fact, coupled with the continuing interest in Ultraflotation phenomena, led to a study to determine the effect of polyvalent metal-silicate hydrosols on the flotation of calcite.

Jan 1, 1978

By Walter R. Lawrence

Newmont Gold Company, formerly Carlin Gold Mining Company, is a publicly owned corporation, 95% owned by Newmont Mining Corporation. Newmont Gold Company has operated gold recovery operations North of Carlin, Nevada, since 1965. Development of the Gold Quarry ore body, 19 kilometers south of the original mine, resulted in the decision to construct gold recovery and ancillary facilities in what is referred to as the Southern Area. Plant No. 2, located 11 kilometers North of Carlin, Nevada, was designed to treat 6350 tonnes per day of oxidized gold bearing ore assaying 2.5 grams per tonne of Au at an average recovery of 87%. Flowsheet development conducted by Newmont personnel resulted in the decision to construct a carbon-in-pulp recovery circuit preceded by two-stage grinding, Detailed engineering was done at Toronto by Bechtel of Canada beginning on January 1, 1984. Actual construction began on March 1, 1984, and was completed in June, 1985. First feed was run on June 22, 1985.

Jan 1, 1987

By Sahendra Ram, Priyadarshi Onam, Abhishek Kumar Singh

A numerical simulation study is carried out for assessment of stability of coal pillars having dirt bands by varying its size and depths. Physico-mechanical properties of dirt bands including thickness and its position in pillar system are varied in the simulation study. Results of the simulation study are correlated with the available empirical approaches of pillar strength are validated with field observations. It is observed that the presence of weak dirt bands significantly influences the strength of pillar. An attempt is made to develop correction factor for the available empirical approaches, which are developed without considering the weak dirt bands in pillar system. The findings of the study will be helpful for suitable design of different size of coal pillars at different depths and stages of depillaring operations.

Feb 1, 2025

By Takashi Sasaoka

About 200 M tons of coal were imported into Japan in 2007 and Indonesia was its second largest exporter, accounting for about 30 M tons (12% of the total imported coal). Indonesia produced about 200 M tons of coal, about 75% of which was exported in 2007. As the Indonesian government has decided on an energy policy wherein 33% of the country?s primary energy demand will be met by coal by the year 2025, the domestic demand for coal has increased dramatically in recent years. Over 99% of the coal produced in Indonesia comes from surface mines. However, the conditions of surface mines are worsening each year: the stripping ratio is increasing, approaching the economic ratio, and the infrastructure for coal from inland mining areas is insufficient for such intense mining operations. To meet the demand for coal in Indonesia and the rest of the world, underground mines have to be developed. However, mining engineers and/or miners in Indonesia do not have a lot of experiences, expertise and know-how concerning the plans and operations of an underground coal mine. In addition, the industry faces a lot of problems which include poor conditions such as a steep coal seam, groundwater problem, stability of highwall, etc. Under these situations, a mine targeted in this research attempts to develop a new underground mine from an open-cut highwall because the stripping ratio in the surface mining area has almost reached the limitation of economic value. This paper discusses the possible development of a new underground coal mine from an open-cut highwall by means of field observation and numerical analysis.

Jan 1, 2009

By A. W. Randall

Geological Aspects of Ore Reserve Estimates of Pine Point District Zinc- Lead Deposits, N.W.T. Zinc-lead ores of the Pine Point District, Northwest Territories, Canada are hosted in paleokarst cavities within a Middle Devonian carbonate barrier complex. Of the nearly 100 deposits found, most are irregularly distributed along two main regional stratigraphically controlled trends. The ores, which occur predominantly as open space filling, form deposits most of which average one million tonnes in size with an average grade of 10% combined zinc plus lead. Geological features related to karsting control not only distribution of deposits but also their shape, size and grade. The higher grade ore in these deposits generally occurs in a relatively small core area. Consequently, accuracy of reserve estimation is dependent on drill hole density and understanding of karst geometry. Several case examples will be reviewed to demonstrate the relationship between shape, size and grade of deposit, geological reserves and drill hole density, along with a discussion of geological ore reserve estimation methods.

Jan 1, 1985

By W. K. Dressel

Over 2 million tons of steel furnace dusts are produced each year in the United States. Recycling of these dusts rather than disposal would conserve mineral resources, reduce land requirements for disposal, and decrease pollution. In addition to the iron content, the dusts contain appreciable amounts of zinc and lead. Removal of lead and zinc with simultaneous reduction of Iron oxide has been achieved by inert atmosphere roasting of carbon-containing pellets prepared from steel furnace wastes. High- and low-carbon wastes were blended to obtain mixtures with sufficient carbon to serve as a reductant during subsequent roasting. The mixtures were pelletized with the addition of bentonite and water, and the dried pellets were roasted in a stream of nitrogen at temperatures ranging from 900" to 1,150° C. Zinc and lead contents were reduced to the 0.1 percent level or less by roasting mixtures containing as little as 7 percent carbon for 1 hour at 1,100° C. ton metallization increases with available carbon content; 50 percent metallization is achieved with 7 percent carbon, 85 percent metallization with 12.5 percent carbon, and over 95 percent metallization when the pelletized mixtures contained in excess of 20 percent carbon.

Jan 1, 1973

By Leonard N. Hill

Cyprus Sierrita Corp. has 16 parallel 5.03 m-diam x 5.8 m long (16.5 ft-diam x 19 ft) primary ball mills, each operating in closed circuit with a nest of cyclones. Before the upgrade to 840 mm (33 in.) cyclones, each mill operated with a nest of five 660 mm (26 in.) cyclones - four in use and one on standby. In this configuration, the mill throughput was 88.5 kt/d (97,500 stpd). Flotation feed averaged 25.9% +212 pm (+65 mesh). The 660 mm (26 in.) cyclones normally operated at an inlet pressure of 34 kPa (5 psi), lower than the inlet pressure of 55 kPa (8 psi) recommended by the manufacturer. The circuit was typically operated with cyclone overflow densities greater than 40% solids to achieve the required throughput. This resulted in inefficient cyclone operation and excessive coarse oversize reporting to flotation. The apexes choked frequently. Larger apexes were tested but reduced the classification efficiency and resulted in circulating loads greater than 800%.

Jan 1, 1994

By L. Alagha, O. Molatlhegi, S. Khatibi

"In the present study, the effect of organic/inorganic (hybrid) polyacrylamide polymer on fine coal flotation was investigated. Raw coal samples contain about 37% of ash-forming mineral at a feed size of -75 + 38 um were subjected to flotation tests in the presence of in-house synthesized hybrid Al(OH)3-PAM at different polymer dosages and pH values. Results show a significant improvement in both combustible recovery and ash rejection at 1 ppm polymer dosage. Further improvement of combustible recovery was obtained when flotation was performed at pH 5. Interfacial properties of coal particles before and after flotation were examined through electrokinetic (zeta potential) measurements of coal/water slurries. Zeta potential vs. pH curve were established and compared. In the case of raw coal/water slurry, zeta potential-pH curve resembles the ash-forming minerals (silica and clays) more than coal. After Al(OH)3-PAM-assisted flotation, the zeta potential of froth/water slurry shifted to more positive values point which strongly indicates significant removal of ash-forming minerals from coal by Al(OH)3-PAM. INTRODUCTION Coal has been a major commodity in meeting the world energy demand during the past several decades (Milici et al., 2013). According to the international energy agency, global coal demand will continue to increase for the coming decades. With increasing world population, the global electricity demand would also increase as more people would get access to basic electricity especially in developing countries (Maggio & Cacciola, 2012). Due to this increase in energy consumption, operations in coal mining and beneficiation processes have been highly mechanized to meet the demands. This mechanization has increased the quantity of raw fine coal particles produced which contain high amount of ash-forming mineral matter (slimes). Aplan et al., have reported that the major constituents of ash-forming minerals in U.S.A coal are clay minerals such as kaolinite, montmorillonite and illite (Aplan, 1997). Conventional froth flotation for fine coal cleaning suffers mainly from two major problems: 1) Low recovery of ultrafine coal particles due to slime coating by ash-forming minerals, and 2) The lack of selectivity, which results in the flotation of middlings and entrainment of mineral fines in the froth (Polat et al., 2003). Slime coating on both valuable and air bubbles have been proposed to explain the observed reduction in flotation recovery especially when fine grinding is required. In this case mineral matter may be degraded to extremely fine or colloidal sizes thereby creating difficulty in the water clarification process such as flotation. Slimes inhibit bubble-particle attachment, and increases reagent consumption due to the increase in solid/liquid interfacial area, resulting in low coal recovery."

Jan 1, 2015

By W. G. Cornwall

The mining field, inclusive of the treatment plant is located in the foothills, five miles inland from the northern coast of Viti Levu, the largest and most important island of the Fiji Group. Gold and silver occur as tellurides, associated with the sulphides, and as minor occurrences of electrum.

Jan 1, 1975

By B. Bag

Saturated and unsaturated fatty acids are used in the flotation of iron values present in iron ore. Among the several fatty acids, oleic acid and its sodium salt are widely used. To substantiate the flotation results, the quantum chemical calculations of a few such acids have been carried out by adopting the semi-empirical AM1 method. These acids have been further optimized in the presence of an iron atom. The electronic interaction of the polar carboxylic head group of oleic acid with the iron atom is higher compared to the other acids. The numerical results support the flotation behavior of iron ore with oleic acid. Key words: Iron ore, Flotation, Fatty acids, Quantum chemical calculations, Semi-empirical AM1 method

Jan 1, 2009

By Stephen Njoloma, Ivan Hee, Ravi Jain, Mina Shinouda

"INTRODUCTION DC Water’s First Street Tunnel (FST) is comprised of a collaborative effort between DC Water, DC Water’s Project Consultants Organization (PCO) led by Greeley & Hansen and McMillen Jacobs Associates and the design-build team of Skanska, Jay Dee, and Parsons Brinckerhoff. The fast-track project includes elements that were designed by the PCO and released for construction by DC Water prior to Notice to Proceed (NTP) and elements designed by the Design-Builder from 30% to released for construction after NTP. This required effective communication and technical coordination for integrated engineering and efficient construction. The project, constructed in an urban residential neighborhood, included innovative construction methods such as multiple location ground freezing, utilizing a centralized freeze plant, to minimize community impact. The means and methods chosen for cast-in-place shaft linings, precast segmental tunnel lining, microtunneling, sequential excavation method (SEM) adits and near surface elements reflected the immediate and sensitive surroundings, which varied by construction staging area (CSA). Technical aspects of the project, relative to the evolution from pre-bid to construction documents, are discussed along with modified designs to suit means and methods. SCOPE OF WORK In 2012, four major storm events swept through the District of Columbia and hit the Northeast Boundary sewer shed particularly hard with the neighborhood experiencing severe flooding. The extreme nature of the flooding, the damage to private property, and the health risks associated with exposure to sewage led to a multi-agency response and community calls for answers and action. The Mayor assembled a Task Force to evaluate a range of potential actions to address combined sewer flooding including engineering, regulatory, code revision, and management improvements. The Northeast Boundary Neighborhood Protection Project was the outcome of the Mayor’s Task Force; it is a three-step infrastructure initiative designed to offload the undersized sections of the existing collection system that serves the Northeast Boundary drainage area by implementing the McMillan Stormwater Storage Project, First Street Tunnel Project and the future Northeast Boundary Tunnel Project. Until the Northeast Boundary Tunnel Project is completed, the First Street Tunnel Project will add 8 million gallons of combined temporary sewer storage in a new tunnel under First Street NW to relieve undersized sewers that traverse the Bloomingdale neighborhood."

Jan 1, 2016

By John Rajala

The Otjikoto Gold Mine in the Republic of Namibia is located approximately 300 kilometers north of the capital city of Windhoek. The project features surface mining with a modern gravity/carbon-in-pulp mill for ore treatment and recovery of gold. Initial mill design capacity was 2.5 million tonne per annum but then expanded after 9 months of operation to 3.1 million tonne per annum. The technical steps to establish the Otjikoto mill design from process selection in the due diligence stage, through flowsheet development in the feasibility study followed by detailed engineering design are reviewed in this paper along with mill performance during start-up and in 2019.

Oct 30, 2020

By R. A. Ynchausti

In January 1993, Pyramid Resources began implementation of a supervisory expert control system at a U.S Cu concentrator. The objective of this control system was to improve plant profitability through unit operation optimization and integration. This paper documents the key aspects of the project, including: economic and associated benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The implementation of expert control at this concentrator has resulted in an estimated benefit of $50,500 per day. This is a net result of improved tonnage, reduced reagent consumption, improved concentrate grade and reduced energy per ton produced.

Jan 1, 1995

By V. R. Degner

The minerals industry trend toward very flotation machines, exceeding 10 m3, began in the late 1960's and responds to the continuing desire to achieve better plant economics through improved plant floor-space utilization, power requirements, and operational /maintenance manpower heeds. In general, as process design tonnage increases, the benefits of the larger flotation machine becomes more evident. The development of the larger flotation machine can be distingushed from earlier, smaller, machines in demanding a rational "scale-up" procedure to guide the basic design, thereby producing a machine prototype capable of satisfactory-operational evaluation at minimum cost. Proven flotation machine "hydrodynamic" scale-up consideration, successfully applied in the development of both the WEMCO No. 164 (28.3 m3) and No. 190 (42.5 m3) machine will be reviewed, and the resulting economic benefits of large flotation machines in high tonnage applications will be summarized.

Jan 1, 1985

By J. R. Maxwell

The development, commercial installation, and operating performance of large capacity Maxwell Flotation Cells. Volumes ranging from 300 cubic feet to 2,000 cubic feet per flotation mechanism.

Jan 1, 1971

By Thomas A. Simpson

Heretofore, underground coal mines in Alabama have operated under only 60 to 360 meters of cover: however, new mines (at least 5 in the early opening or development stages) will be operating under cover ranging from 600 to 660 meters. With increased rock confining pressures, roof stability problems will become more critical. Initial studies in two 7 ½ -minute quadrangle areas in the Warrior coal basin of Alabama indicate that the orientation of certain lineament and fracture-trace modes mapped from ERTS-1 (Earth Resources Technology Satellite) imagery correlate closely with the strike of joint and fault modes. High altitude (118,000 m) U-2 aircraft data were used to support these findings. In addition, over 50 percent of the normal faults mapped in the study area could be directly correlated with ERTS and U-2 lineaments and fracture traces. These correlations provide clues to the structural development of the Warrior coal basin and may, in turn, be used as a guide to the prediction of roof-stability conditions in advance of mining.

Jan 1, 1975

By Patrick Shea

Old mine workings are found throughout the Western United Sates on lands administered by the U.S. Bureau of Land Management, U.S. Forest Service and private lands. Some of these mine workings date back to the late 1800s. There may be as many as 100,000 sites on lands administered by the National Park Service, U.S. Forest Service and Bureau of Land Management. The U.S. Department of the Interior has worked with the U.S. Geological Survey, the U.S. Forest Service, the U.S. Environmental Protection Agency, and western state governments to identify and prioritize these sites on Bureau of Land Management, National Park Service and U.S. Forest Service administered lands. This presentation will discuss the accomplishments we have made to date to clean up inactive and abandoned mine sites, focusing primarily on lands administered by the Bureau of Land Management.

Jan 1, 2000