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By C. E. Lapple

To improve mine health and safety conditions, there is need for a portable instrument that mine inspectors can use routinely for rapidly checking concentrations of dust in mine atmospheres. On October 23, 1969, Stanford Research Institute was authorized by the U.S. Bureau of Mines to conduct a study aimed at developing such an instrument under Contract No. H0100186. The results of that study are reported in Technical Report No. 1, "Development of Portable Instrument For Measuring Coal Mine Dust Concentration," August 1970. In that study it was demonstrated on bench-scale that a near-forward optical scattering device gives a linear correlation between mass concentration and optical readout over a range of 2 to 200 mg/m3 with excellent reproducibility. The same correlation was obtained for the Respirable* dust fraction of three different coal dusts within ± 10% and an extreme spread of ± 30%. Based on these results a prototype instrument was designed which was expected to meet all the necessary requirements of a portable instrument for mine use. Because of the excellent results obtained, a further study was authorized by the Bureau of Mines on May 10, 1971 under Contract No. H0111688. The prime objective of this study was to build, calibrate, and deliver to the Bureau of Mines two prototype instruments based on the design previously developed. The emphasis was to be on providing instruments which would meet certain minimum standards of size, weight, response time, sensitivity, ruggedness, reproducibility, permissibility, and cost (ultimate); optimization of the design was to be considered only insofar as it would not significantly delay the development. One instrument was to be delivered after initial calibration of both instruments with Coal Dust PGH. The second instrument was to be used for further calibration with a number of other coal and rock dusts and for assessing other relevant performance characteristics. This report summarizes all the results of this second study.

Jan 1, 1972

By Kyle Wagner, William Joa, Colter Angell, Catherine Johnson, Marty Langenderfer, David Doucet

The goal of any business is to seek the maximum profitability for the organization through optimization the use of resources, processes and the application of new technologies. An analysis of various case studies demonstrate that blasting can have positive impacts on the crushing and milling processes resulting in increased profitability for the mining industry (Grundstrom, Kanchibotla, Jankovich & Thornton, 2001). This paper describes the case study of two copper mines in Peru producing Cu-Mo and Cu-Au concentrates, which together with their strategic partner, have implemented a project focused on the improvement of rock fragmentation. The project was based on techniques of pattern size reduction, the use of high energy explosives and the technology of electronic initiation. Combined, these techniques were shown to have significantly impacted the efficiency of downstream processes.

Jan 1, 2019

By J. H. Rowland, R. A. Thomas, III, C. D. Litton

Atmospheric monitoring systems (AMS) are required when using air from conveyor belt entries to ventilate working sections in U.S. underground coal mines. AMS technology has the potential to increase fire safety mine-wide, but research is needed to determine the detection and response times for fires of a variety of combustible materials. To evaluate the potential of an AMS for fire detection in other areas of a coal mine, a series of full-scale fire experiments were conducted to determine detection and response times from fires of different combustible materials that are found in U.S. underground coal mines, including high- and low-volatility coals, conveyor belts, brattice materials, different types of wood, diesel fuel, and a foam sealant. These experiments were conducted in the Safety Research Coal Mine (SRCM) of the U.S. National Institute for Occupational Safety and Health (NIOSH) located in Pittsburgh, PA, using a commercially available AMS that is typical of current technology. The results showed that through proper selection of sensors and their locations, a mine-wide AMS can provide sufficient early fire warning times and improve the health and safety of miners.

Jan 1, 2016

By Kyle Amoroso, Aaron K. McCain

Frozen soil shoring has been used for decades in the tunneling industry to provide temporary support of excavation for shafts and cross-passage excavations. However, horizontal penetrations through the frozen soil can prove to be challenging. The key to creating a stable portal through frozen ground is managing and mitigating groundwater flow into the excavation through the annular space surrounding the drill stem or casing. This paper will review different approaches that have been successfully used to penetrate frozen soil shoring on multiple projects.

Jun 13, 2023

By G. D. Marshall, D. K. Sarin, V. E. Hampton

Ground support at the Thompson Mine emphasizes scaling, rock bolting and wire mesh screening on the backs and walls of all underground stoping and development areas and also full column grouted cable bolting in the bulk mining areas. This paper describes the equipment for the point anchored rock bolts as well as the full column cable bolts. Modifications in design and testing of all components and procedures has ensured a safe and efficient method of ground support for the mining conditions existing at the Thompson Mine.

Jan 1, 1983

By P Lindsay

A numerical model has been developed to simulate the effectiveness and costs of a number of conceptual remedial measures aimed at reducing acidity and metal concentrations in the Ngakawau River and its tributaries near the Stockton Coal Mine, situated on the West Coast of New Zealand. The Stockton Coal Mine has been in operation over the past 100 years. During that time, seepage from waste rock dumps has contributed to elevated acidity and metal concentrations in the Ngakawau River and some of its tributaries. The yearly mean rainfall at the mine site is 6000 mm. The model, developed using GoldSim software, simulates rainfall, run-off and stream discharge for 26 tributaries. It then calculates acidity and metal concentrations in the mine impacted tributaries and the dilution downstream from the mine. The model has been calibrated to measured flow and acidity and metal concentrations in the Ngakawau River and some of its tributaries. Acidity and metal loads are removed from the system in accordance with specified efficiencies and capacities of the respective conceptual remedial measures. The user can compare specific remedial measures, or a combination of conceptual remedial measures. The model predicts the acidity and metal concentrations at a number of monitoring stations for any remedial strategy selected by the user. It also calculates the capital and operational costs for that particular remedial strategy. This paper presents the development of the numerical model and describes how the end-user can use it to compare the efficiency and costs of various remedial strategies by running different æwhat ifÆ scenarios.

Jan 1, 2006

By A Poliakov, E Donskoi, K Vining

The automated optical image analysis software Mineral4/Recognition4 (M4/R4) is capable of performing comprehensive characterisation of different materials throughout the iron ore value chain, including ore fines, lump, sinter, pellets and coke. It has been successfully used by CSIRO for industrial and research projects and has been independently licensed to several world leaders in iron ore production and ironmaking. The M4/R4 software was strongly integrated with a Zeiss microscope to make use of the company’s powerful AxioVision software. This required users to own both Zeiss microscope hardware and AxioVision software in order to be able to use M4/R4 to its full image acquisition and analysis capacity. Therefore, it was not available to the users of equipment produced by other major microscope manufacturers. In recent times however, Zeiss has indicated that the AxioVision software will no longer be supported. To overcome this limitation, CSIRO has proceeded with the next generation of this software, Mineral5/Recognition5 (M5/R5). Importantly, the M5/R5 system has been developed without any dependence on a specific microscope hardware/software platform. Furthermore, the image analysis functionality is now based on openCV open access software and has been fully rewritten using stateof- the-art software development tools to allow reading and processing of all major image formats. Although past applications have been specific to iron ore and ironmaking applications, other improvements, such as an increased number of minerals allowing better gangue segmentation, flexible mineral definitions, improved software modules behaviour and refined analysis routines enables the platform independent M5/R5 image analysis system to be used by researchers in any area of mineralogical or materials research.

Nov 8, 2021

By F. W. Willard

VIEWING with alarm is a preoccupation not exclusively the habit of the political spellbinder. In good faith many of our mineral technologists have been and are genuinely alarmed over the prodigal consumption of our mineral reserves. Most competent observers are cautiously pessimistic. There are sound technical reasons for such caution. It is the purpose of this paper to discuss some of those reasons without benefit of a gift of prophecy. Perhaps the outstanding reason for caution is ignorance of accessible but undiscovered mineral reserves. The petroleum technologists have an edge on their metallurgical brothers for they have better tools for exploration. This is not to say that the mining geologist has to depend on hunches or the divining rod. The outstanding work on orogenesis by Lindgren and others has provided the mining geologist with some sound scientific knowledge as to where accessible metallic minerals are most likely to be found, As Clinton H. Crane has recently observed, most of the accessible areas of the earth have been combed for easily identified outcrops, and those have been or are being actively exploited. To find ore bodies hidden below the surface is still a costly speculation.

Jan 1, 1946

By Ray Mason, Damien Label, Howard Bernier, Kevin McDermott, Kevin Coombs

"GeneralWabush Mines is an unincorporated joint venture of seven steel companies and Pickands Mather & Co. The mining and concentrating facilities are located in southwestern Labrador and the pelletizing and shiploading facilities are at Pointe Noire, 200 miles south, near the town of Sept-lies.The operation is based on a 5 ½ sq. mi. specular hematite deposit with a reserve of 375 million tons of concentrate. Annual production capacity is rated at 6 million tons of pellets per year. The final upgrading process utilizes high-tension separation of silica following wet autogenous grinding, spiral gravity separation and fluo-solids drying. The concentrate is railed in closed cars to Pointe Noire. The concentrate is reground dry and pelletized on Dravo Lurgi travelling grate machines to produce an oxide pellet with 65.5% Fe, 3.0% Si02, 1.95% Mn and 93.5% Tumble Index.HistoryPlant operations commenced in 1965 with a concentrator capacity of 5.3 million tons per year and a pelletizing capacity of 4.8 million tons per year. The original facilities for classifying the crude ore into fine and coarse fractions for storage purposes before reblending as autogenous mill feed were found to be unnecessary and were by-passed after plant startup. Capacity of the operation was increased to 6.0 million tons of pellets per year in 1968. This increased capacity required the installation of an additional160 cleaner spirals in the ore dressing plant, a new 5000 hp ball mill, three balling circuits and increased cooling air capacity in the pellet plant.In 1970, the regrind circuit in the pellet plant was converted to dry grinding and a significant reduction in grinding media consumption and maintenance costs was realized. A ninth grinding mill of 5000 hp capacity was installed to compensate for the reduced capacity in going from wet to dry grinding."

Jan 1, 2000

By W. Krieglstein

Due to the natural variability of ores, it is necessary to carefully test flotation behavior of flotation cells before designing flotation circuits. For performing quick and versatile tests in the laboratory, Siemens developed a laboratory-size Hybrid Flotation Cell, which has been down-scaled from the 300 m³/h production cell to a 0.6 m³/h flotation cell. This small cell is being used as a test bed for technical and chemical concepts, the improvement of decisive components and the characterization of customer ores. In this study the evaluation results for Andean porphyry copper ores are shown. Total recovery rates of the order of 45 to 50 % have routinely been achieved in a single flotation cycle over a wide range of feed grades. In addition, the Hybrid Flotation Cell has proven to be particularly well suited for the flotation of fine particles below 20 µm down to below 1 µm, at high recovery rates and concentrate grades.

Sep 1, 2012

By V. ?. Chanturiya, I. Zh. Bunin, M. V. Ryazantseva

"Surface changes in naturally occurring metal sulfides (pyrite, arsenopyrite, sphalerite, chalcopyrite, galena, and molybdenite) due to treatments from high-power electromagnetic pulses (HPEMP) at varying times were studied using X-ray photoelectron spectroscopy. Analysis of the obtained results revealed common patterns and differences in surface transformations. The transformations were found to include two main stages. The first stage was observed at low treatment intensities (up to n ~103 pulses). At this stage, formation and accumulation in the surface layer of the nonstoichiometric sulfide phase, oxides and hydroxides, as well as elemental (polysulfide) sulfur and/or metastable sulfur species (thiosulfate, sulfite) was observed. The second stage (N = 3·103 pulses) is characterized by thermal removal of sulfur species and renewal of the mineral surface (sulfidization).It was found that the chemical changes of the sulfur on the surface layer of pyrite, arsenopyrite, chalcopyrite included accumulation/formation of S0 (Sn 2-) at the first stage of the transformation, followed by its removal. An increase in the surface concentration of elemental sulfur for pyrite and chalcopyrite was 10–12% while arsenopyrite was approximately 5%. A more complicated chemical change was observed for sphalerite and galena, that included formation/accumulation of metastable sulfur species (thiosulfate, sulfate) at the initial stage (up to 103 pulses) and during longer treatment times, the sulphur is reduced back to its initial state (sulfide or disulfide). The increased concentration of S0 sulfur, compared to the original sample, was only 3% in galena and sphalerite.The application of HPEMP treatment to improve flotation selectivity is supported by singlemineral flotation tests. Changes in flotability as a result of HPEMP treatment are principally explained by surface phase changes that resulted in higher adsorption activity."

Jan 1, 2016

By J Rose, D O’Toole, D Grant

Orepasses are a critical element in the transport of ore from the stope drawpoint to the surface ore stockpile, making them an integral part of an underground mine’s ore-handling system. Well-designed and operated orepasses improve productivity and lower operating costs over a long period of time.The Olympic Dam mine, as part of a 6 Mt/a expansion project in 1997, constructed a large network of orepasses feeding a rail haulage system to facilitate the movement of approximately 8 Mt/a to the Clark crusher and hoisting shaft. The orepass network comprises 14 orepasses and currently includes 59 individual tip points. The orepass network has been in operation for over 15 years and in excess of 110 Mt of ore has been moved through the system.Olympic Dam’s management of mine infrastructure includes a program of assessing the condition of the Clark system orepasses. A comprehensive program was initiated in 2011 and consisted of systemically performing volumetric surveys to determine the integrity of the various sections of the orepasses. The current geometrical state of the orepasses provides essential information for comparison of geotechnical and operational parameters and a baseline for understanding the key causes of orepass deterioration to assist in the planning of both usage and potential replacement options.The collection of geotechnical and operating data allowed the review of the current condition, potential longevity and associated risks with the various orepass sections. Initial studies have also reviewed options for rehabilitation and/or replacement.CITATION:Rose, J, Grant, D and O’Toole, D, 2016. Orepass monitoring and management at Olympic Dam Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 609–616 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By W Patton

Investment decisions in the mineral resources sector are made on the basis of an assessment of the economic potential for a mineral deposit. Given the supporting information for the location, scale, and quantity of the commodity of interest, miners and investors aim to make risk-informed decisions when considering further investment. The objective of resource classification is the synthesis of various types and quantities of geologic information used in resource model construction to assign confidence categories to the estimated mineral resources, which can then be used to support informed economic decisions. In this paper a risk-based classification scheme for iron ore mineral resources using conditional simulations is presented. The method involves categorisation of each block according to a confidence level, considering expected recoveries from a kriging model over mining production volumes. The realisations of the simulated model are used to assign risk-based confidence categories to zones of the ore deposit. One motivation for this work is to assess the sensitivity of the scheme to geologic uncertainties. Specifically, that which uncertainty in the layout of mineralising alterations and weathering overprints influence variabilities of associated rock properties and the likelihood of obtaining expected ore recoveries. It is shown these risks have material implications for a project’s economic potential. How the scheme can be extended to the grade control context and the value subsequent grade control activities is also quantified.

May 24, 2023

There is a strong demand for nickel metal due to quick development of stainless steel and new electrical materials, most of which is extracted from sulfide resources, resulting in a serious depletion of sulfide resources. Therefore, more attentions have been paying to extracting nickel from nickel laterite, which accounts for some 50% of total nickel metal production. In this paper prereducing?magnetic separation?reduction smelting process is developed to manufacture ferronickel rom two types of nickel laterite DN and GN, assaying 1.42% 1.83% Ni and 49.09% 26.08%Fetotal, respectively. Mineralogy of two types of nickel laterite was determined and optimization of process parameters was conducted to manufacture ferronickel. Prereduction?magnetic concentration process is used to upgrade low grade nickel laterite firstly, two kinds of Ni-Fe concentrates being prepared of DN assaying 2.26% Ni and 69.45% Fetotal and GN containing 2.76% Ni and 38.00% Fetotal. Finally, two types of ferronickel were produced by reduction smelting of prereduced concentrates DN and GN, DN and GN ferronickel contains 2.97% Ni and 6.58%Ni, 89.25%Fetotal and 89.95%Fetotal, respectively. The total recoveries of Ni and Fe of the two ferronickel are beyond 90% and 80%, respectively. There is significant difference in grade of magnetic concentrates and ferronickel between DN and GN laterite due to their different mineralogy, the former belongs to limonitic laterite and the latter saponite one. There are some advantages for this process to manufacture ferronickel from nickel laterite, including effectively upgrading low grade nickel laterite by prereducing?magnetic separation technique, higher throughput and lower energy available for reduction smelting section due to some 40% gangue being rejected in pre-upgrading section, and much less metallurgical coke consumption by using non-coking coal as reductant for prereducing?magnetic separation?smelting process.

Jan 1, 2014

By J. D. McKay

Continuous column flotation parameter testing, to improve operating methodologies, using coarse bubbles on fluorite ore from Nevada, revealed that retention time is the predominant factor affecting column flotation fluorite recoveries. Column height and feed injection location affected fluorite grades and recoveries because they affected particle retention times in the collection and cleaning zones. Other parameters tested, including froth depth, wash water addition, and axial mixing, showed varying results. Four defined zones within the column were found to have characteristic rates of upgrading per vertical foot. Fluorite-gangue separation was more efficient in a column than in a conventional cell at all particle sizes.

Jan 1, 1987

By M I. Pownceby, M A. Rhamdhani, D M. Fellicia, S Palanisamy, R Z. Mukhlis

The trend of global copper production has prospectively increased over time. Based on typical mined ore grades, 1 t of copper ore generates approximately 6–10 kg of copper, which requires much energy, usually in the form of metallurgical coke. Copper production using carbon as a fuel and reductant contributes up to 0.3 per cent to global greenhouse gas (GHG) emissions. As a result, research into decarbonisation processes applicable to reducing low-grade copper sulfide ores, copper oxides, electronic wastes and other alternative complex Cu-rich materials has increased. Alternative fuels for reducing carbon-rich emissions in pyrometallurgical copper processing include methane, ammonia, biomass, solar and wind power, but in recent times increased focus has been on hydrogen as a potential fuel and reducing agent for materials such as oxidised copper scrap, Cu2O/CuO and Cu-rich slags/e-wastes. From a thermodynamic perspective, hydrogen exhibits a significantly more negative standard Gibbs free energy (ΔG°) than copper oxide making it a suitable reductant and the exothermic thermal effect from reaction between hydrogen and Cu2O/CuO may be used to control process parameters. These characteristics renders hydrogen an ideal gas for reducing copper oxides and copper-containing slags/e-wastes. This review article assesses previous research on utilising hydrogen for producing and refining copper from primary and secondary feed materials.

Jun 19, 2024

By J. Zhang, A. J. S. Spearing, L. Ma

Ore deposits are becoming more complex to mine as a result of the exhaustion of surface and other easily mined deposits. There is also increasing socio-political pressure to design more environmentally sound, sustainable, and safe mining practices. Wang and Ma designed a mining method for coal, similar to a modified drift and fill using a continuous miner to take sequential cuts (rooms) that are subsequently backfilled. The authors have modified the concept to make it more autonomous, safer, and less costly using highwall coal mining techniques, modified and adapted for underground applications. The method is more flexible than longwall mining and the percentage extraction would seem to be in the same range. In addition because of the backfilling, surface subsidence would not be a major issue and could be more effectively managed.

Feb 2, 2021

By Thomas Billups, Brendan FitzPatrick, Doug LeDo, David Carchedi

"Working in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. This paper describes the use of the modular Ductile Iron Pile system, a low-vibration driven micropile, on two urban projects on the Johnson & Wales University campus in Providence, Rhode Island. The paper describes the successful implementation of Ductile Iron Piles installed to develop capacity in end-bearing on one site and friction on the second site. Design, installation and quality control operations are all presented as well as the results of full-scale load testing performed on non-production test piles. This paper is of importance to the industry because it describes a versatile option for project teams as an alternative to traditional micropiles, helical piles or other deep foundation systems for urban sites.INTRODUCTIONWorking in urban environments presents unique logistical challenges beyond those typically associated with traditional geotechnical analysis and design. These challenges often include working on sites with limited access and laydown area, vibration concerns for adjacent structures and the need to work from variable elevations or within excavations. Two recent projects in downtown Providence, Rhode Island faced a combination of problematic soil conditions and urban construction challenges including vibration concerns. Both projects were a part of the Johnson and Wales University campus development. Figure 1 illustrates the urban locations of the sites."

Jan 1, 2016

By A. Santana, J. Jankolovits, G. S. Reyes

The flotation of sulfide ores that contain carbonaceous gangue requires significant operational and chemical intervention to achieve suitable metallurgical outcomes. Carbonaceous gangue dilutes concentrate grades, alters the froth behaviour, reduces operational stability, adsorbs reagents, and reduces value recovery. Carbon management processing strategies like preflotation and depression are often presented as point solutions. Moreover, oversimplified mechanisms of carbon depressants belie their complex and nuanced impact on flotation behaviour. Optimising the flotation of carbonaceous sulfide ores requires a holistic consideration of interactions between the carbon management reagents and the processing strategy, ore mineralogy, flotation behaviour, flowsheet, and all other aspects of the flotation system. Examples are shown where conventional, simplistic mechanisms of carbon depressants fail to explain the observed flotation behaviour. The multifaceted impacts of carbon depressants on froth behaviour, collector performance, and value recovery highlight the need for a holistic approach to carbon management. Keywords: Carbon management, carbonaceous ores, sulfide flotation, carbon depressant

Jan 1, 2020

By Chuanhui Cao, Shimei Liu, Xiaojing Li, Yueyuan Zhou

"Force analysis on weakly-magnetic particles and non-magnetic particles in magnetic field are presented, using a kind of permanent magnetic drum magnetic separator, which is designed with strong specific magnetic force and open magnetic system. Its surface peak intensity reaches to 1.0T, and the distribution density of capture line is 1.25×103/dm2. Qualitative analysis on the particles including its magnetic property, particle size, motion speed, magnetic field intensity, etc. is also presented to calculate the separating parameters for the drum separator. Experiment was conducted for the separation of fine weakly magnetic minerals for example ilmenite. The practicability to separate the minerals using separator designed with open magnetic system has been proved, providing an economic way for efficient separation of micro-fine weakly magnetic minerals and upgrading of non-metallic minerals. INTRODUCTIONMagnetic separation is a mineral processing method based on the differences of magnetic properties between minerals in inhomogeneous magnetic field (Sun, 2007). Currently for separation of micro-disseminated weakly magnetic iron ore, electromagnetic high intensity magnetic separators with closed structure of magnet system are often used. And for the separation of strongly magnetic minerals such as magnetite, low intensity drum magnetic separators with open magnet system are often used. In order to lower the operation costs and improve energy efficiency, it is important to develop efficient high intensity permanent magnetic separator with open magnet system, to some extent replacing high intensity electromagnetic separator.Oberteuffer (1974) discussed the magnetic force and competing forces in magnetic separators which compete with the magnetic forces and act on all of the particles which travel through the separator are those of gravity, hydrodynamic drag, fraction, and inertia in magnetic separation."

Jan 1, 2016