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By Verya Nasri, Behrouz Esmaeilkhanian, Mohammad Motallebi

Réseau Express Métropolitain (REM) is the new Light Rail Transit (LRT) network of Montreal, Canada. This new LRT network uses a century-old Mont Royal Tunnel (MRT) to connect Downtown Montreal to the north side of the Island of Montreal by passing through Mount Royal Mountain. This railway double track horseshoe tunnel is approximately 5 km (3.1 mi.) long, 8.8 m (29 ft.) wide and 5.5 m (18 ft.) high, with a constant 0.6% grade. Due to different geological characteristics of the surrounding ground, varied from hard rock to soft soil, different cross sections and excavation methods were adopted for construction of this tunnel. In order to use MRT in the modern transit system, the tunnel needed to be inspected, rehabilitated and be compliant to the recent safety standards. This paper presents a summary of history and characteristics of the existing tunnel plus the implemented steps to upgrade the tunnel. It includes the details of the structural inspection and rehabilitation methods of the tunnel. Further, this paper summarizes the procedures for the space proong, construction of the separation center wall, and the tunnel enlargement. It also describes parts of complications encountered during the construction and solutions implemented to tackle these issues.

Jun 23, 2024

By D. P. Patil, B. K. Parekh

Water is the mainstay for beneficiation of fine size coal and minerals; however, it is also the least desirable constituent in the final product. The basic concept of the novel process described in this paper is based on the differential surface heat conduction/ absorption capacity of individual particles, which differs for different species of minerals. When a mixture of fine material is exposed to a radiant energy source, the various solids present in the mixture will absorb heat energy depending on their heat-conducting properties and there will be a difference in the surface temperature of the particles. When this differentially heated solid mixture is placed on a moving belt, which is coated with a low temperature melting resin, the hotter component of the mixture will stick to the belt and relatively cooler particles will stay free on the belt and fall off at the end of the belt run. Experiments were conducted with pyrite, coal, and quartz of 6 × 18 mesh particle size. The goal of the test program was to find the optimum conditions at which there exists a required temperature difference between minerals and coal particles by controlling the operating system variables. Preliminary tests results showed that there is a potential for separating mineral matter from coal using the thermo-adhesive separation technique.

Jan 6, 2022

By J. Douglas

The past year has been a strange one for the fertilizer industry of the world and the United States. Listening to news stories, you would think the sky is falling on the world's agriculture and probably conclude that we should have had an exceptionally poor fertilizer season. In some respects, we did. Prices were low, profits were low, and in some cases nonexistent, but volume was good. We heard much in the press about the farmers' credit crunch. The truth of the matter is that only 6.6 percent of the U.S. farmers have debt-equity ratios of 70 percent or more, and a large percentage of our farmers have absolutely no debt but operate entirely on their own cash assets.

Jan 1, 1985

By M. SIDDARAJU, Rameshwar Sah, T. Umadevi, K. S. SRIDHARA, M. RAJU, GANESH SHETTY

With the depletion of high-grade iron ore resources, the utilization of existing low-grade iron ores, fines and tailings with effective beneficiation is inevitable to meet the iron and steel industry’s required specifications and demand. JSW Steel Limited is operating a 17-mtpa beneficiation plant at its Vijayanagar site in Bellary in Karnataka, which produces nearly 50 to 54 percent concentrate as sinter-grade fines. The sinter base mix consists of iron ore fines that are smaller than 10 mm, with 41 percent smaller than 0.150 mm; washed ore that is generally smaller than 3 mm and bigger than 0.150 mm, with 3 to 9 percent smaller than 0.150 mm; beneficiation plant concentrate, with 97 percent smaller than 0.150 mm; limestone; dolomite; coke breeze; lime; sinter return fines; direct reduced iron (DRI) fines; and micropellets produced from steel plant waste. Using more washed ore in the sinter base mix affects the sinter quality. Ball formation in the mixing and nodulizing drum is an important step in sinter making and requires sufficient quantity of smaller than 0.150 mm fines. Optimization of fines in the sinter base was carried out by replacing the smaller than 10 mm iron ore fines with washed ore. Size analysis, study of the granulation index (G index) and optimization of moisture with respect to sinter bed permeability were carried out to optimize the proportion of smaller than 0.150 mm fines in the sinter base mix as adhering material. This study explores the optimization of fines in the sinter base mix for ball formation to achieve higher sinter quality and productivity with higher sinter bed permeability.

By T. V. Falkie

REMARKS OF DR. THOMAS V. FALKIE, DIRECTOR, BUREAU OF MINES, U.S. DEPARTMENT OF THE INTERIOR, BEFORE THE FALL MEETING OF THE SOCIETY OF MINING ENGINEERS, AIME, ACAPULCO, MEXICO, SEPTEMBER 23, 1974 This is a time of uncertainty on the world mineral scene. For some of the world's so-called "developed" countries, reserves and production of key minerals are running low. And, we have learned that the energy so essential in recovering and processing minerals can suddenly be in short supply. The prospects for a "no growth" situation in energy or mineral consumption are practically nil. Moreover, the world's economy is in flux, casting doubt on whether traditional mineral customers will continue to be able to buy, or for that matter, whether traditional suppliers of minerals will continue to sell. It is clear that the mineral situation is contributing to world inflationary pressures, which incidentally are most damaging to developing countries. So it is appropriate that SME members devote this session to the world mineral situation, and consider some of the opportunities and responsibilities that we will inevitably encounter as the future becomes the present. The opportunities, to me at least, are especially intriguing, I have the good fortune to be part of an organization that has an enormous capability and responsibility for dealing with mineral problems. The Interior Department's Bureaus, including the Bureau of Mines, have been around for a long time. They are. a prolific and reliable source of both mineral information and mineral technology.

Jan 1, 1974

By Ralph C. Flow

In Cleveland County, North Carolina, one and one-half miles south of Kings Mountain, Foote Mineral Company operates an open pit for the production of spodumene, feldspar, mica, and commercial stone. Spodumene concentrate is sent to Footers Sunbright, Virginia plant and to other customers. Exton, Pennsylvania and New Johnsonville, Tennessee plants produce lithium compounds sold to the oil industry for multipurpose lithium-base greases, to the metal industry as welding flux, to the air conditioning market, and to the glass industry. Ceramic grade spodumene, feldspar, and mica concentrates go to other processing companies from the Kings Mountain plant. Waste amphibolite is delivered to a neighboring quarry operation.

Jan 1, 1962

By James R. Arnold, John G. Mansanti

BACKGROUND Gold Fields Mining Corporation started their Chimney Creek operation in late 1987. The dump leaching operations commenced in October and the mill startup took place during the last half of November. The milling process at Chimney Creek is almost a conventional CIP plant with the major exception being the installation of a second thickener as a washing stage prior to CIP12 ' A simplified flow sheet is shown in FIGURE 1. Most of the gold in the mill is liberated by grinding in cyanide. After grinding in a conventional SAGball sill circuit, the cyclone overflow reports to the thickeners. The thickener overflow from the first thickener is pumped through 5 stages of carbon columns for gold adsorption. Slurry from the thickener underflow is leached, washed, re-thickened and pumped to CIP. After approximately 6 hours of retention time in CIP, the slurry is pumped to tailings for final deposition. The carbon from CIP is transferred to the third stage of carbon adsorption and then advanced as normal through the columns and strip circuit. Loaded carbon is stripped at approximately 1500C (3000 F) and 55 kPa (80 psi). After 4-5 hours of stripping, the grade of four tons of carbon is reduced from 5,140-6,860 g/t (150¬200 oz/ton) to typically 17 g/t (0.5 oz/ton). Zinc precipitation is used to recover the gold from the pregnant solution. After a water wash, the stripped carbon is transferred to acid wash or to the kiln feed tank for reactivation. All strip lots are acid washed in 3.0% HC1 and all stripped carbon passes through the kiln for thermal reactivation. Then the carbon is quenched, sized and stored in tanks or bins for transferral to CIP or to the carbon columns. Loaded carbon from the dump leach circuit is treated in a circuit consisting of five carbon columns which are parallel to the mill circuit. No distinction is made between the mill or dump leach carbon once the gold has been stripped from them. CARBON FINES HANDLING Once the carbon has been transferred from the carbon columns, every effort is made to minimize carbon attrition and to recover the carbon fines that have been generated in the process. Wemco Hidrostall pumps are used for transferring all carbon in

Jan 1, 1990

By J. A. Hartlage

Four years ago, Ashland Chemical Company introduced a new copper solvent extraction reagent for hydrometallurgical utilization. The reagent, an alkylated 8-hydroxyquinoline, is called Kelex 100 ®(1). Since the time of introduction, the reagent has been investigated by several workers for its solvent extraction utility in the separation and purification of transition metals (2-7). In the following text, those factors which are essential to the optimum performance of Kelex 100 on concentrated copper solutions will be discussed. To date, the reagent has been found useful in active concentrations of from 1 to 20% Kelex 100. In order to achieve the best performance for Kelex 100, it has been found that a phase modifier is essential. Various alcohols and phenols have been evaluated in order to improve phase performance and stripping characteristics of the solvent system. Modifiers and diluents are especially important when solvent activities between 3 and 20% Kelex 100 are employed. A 15% Kelex 100 solvent, for example, containing 15% nonyl phenol in Escaid 100 (Exxon) can be utilized to remove greater than 33 grams per liter of copper from an aqueous feed without interstage neutralization, and in the same process scheme the reagent can be stripped to less than 1 gram per liter barren organic producing a pregnant electrolyte containing greater than 40 grams per liter copper and less than 120 grams per liter sulphuric acid. The unusually efficient stripping of Kelex is accomplished by protenation of the extractive molecule during the stripping process.

Jan 1, 1974

By X. P. Zheng

Barium fluorphlogopites were synthesized in the laboratory in order to investigate the effects of composition and crystal parameters on surface properties and floatability. The negative surface charge of mica is determined by the barium content, the crystal cell volume, the distance between layer structure and the Ba-O bond length. The higher barium content, the larger the cell volume and distance between the layer structure and the longer the Ba-O bond, the more negatively charged the surface is and hence the more easily adsorbed to cationic collectors. When an anionic collector (sodium oleate) is used, barium oleate forms on the mica surface and hence chemical adsorption occurs.

Jan 1, 1993

By J. J. Bean

The development drilling program of the Copper Cities mine indicated that the molybdenum content of the ore would be about 0.011% MoS2' The molybdenum content of the Miami mine at the same time was about 0.025% MOS2' The Miami mill had a very successful molybdenum operation which used bleeder turbine steam from the Miami power plant for the steaming operation. The much lower grade of the Copper Cities ore, the absence of a source of low cost steam and the use of sodium aerofloat as the copper collector which Miami experience indicated did not respono readily to the steaming technique made very doubtful the success of a similar operation at Copper Cities. However, the relatively few pounds of copper that could be recovered from the low grade Copper Cities heads made very desirable the recovery of the molybdenwa,as a source of additional revenue. Accordingly, shortly after the Copper Cities mill began operation, a research program was instituted to develop a suitable method of molybdenum recovery. This program explored first, the successful steaming process then in use at Miami and as expected, found it unable to decompose the sodium aerofloat copper collector. The known chemical depressants were then tried without much encouragement. Finally the copper concentrate was dried, not roasted, to 2-3% mOisture and this along with sodium ferro-cyanide and cyanide resulted in sufficient copper depression that a final molybdenum concentrate containing 1.0% CU could be made. The bench scale testing was followed by pilot plant testing. Sixteen

Jan 1, 1972

WELCOME to the world-class Cripple Creek district where gold exploration and production continue 95 years after the initial discovery. More than 21 million troy ounces of gold have been recovered, valued at greater than $7.8 billion using today's gold price ($371/oz). The Cripple Creek district is localized within and around the margins of a silica-undersaturated alkalic diatreme-intrusive complex. The diatreme appears to be comprised of three sub-basins: 1) a sub-basin east of the Cresson (Fig. 1); 2) a southwestern sub-basin between Victor and Cripple Creek; and 3) a northwestern sub¬basin within which the Globe Hill and Ironclad pits (Fig. 1) are located. The recognition of three separate basins was made by G. F. Loughlin and A. H. Koschmann (1935, Fig. 8) who prepared a contour map on the floor and walls of the composite Cripple Creek basin. The northwestern and southwestern sub-basins are apparent due to the discontinuous exposures of a partially exhumed ridge of Precambrian rocks (Fig. 1). The separation of the eastern and southwestern sub-basins was recognized in mine exposures where a fault-bounded ridge line extends from the vicinity of the Ajax mine toward the Precambrian "island" (Fig. 1).

Jan 1, 1986

By T. BACHMANN, G. SHAPLAND, E. Amini, N. BEATON, M. BECERRA

Process plant modeling in the computer environment has been developed over the past 40 years by implementing the comminution models formed by the Julius Kruttschnitt Mineral Research Centre, University of Queensland, in the early 1970s. The models for the other processes in a mine value chain, such as blast fragmentation and flotation, were continuously developed and improved in parallel as well. Other research and commercial entities have also developed process modeling methodologies in the computer environment, which evolved as specialized commercial software or through equations set up in Excel spreadsheets. These were performed on a local computer, in thousands of simulations over a long period of time due to hardware limitations and the lack of a fully automated process. This limits the application of detailed process simulations for scale-up and strategic planning analysis, as they require many simulations to cover all possible scenarios which would take a lifetime when using local computers. The Integrated Extraction Simulator (IES), as the next generation of cloud-based software package, has made it possible to run simulations on the entire operation value chain in the same platform, including drilling and blasting, crushing, grinding, flotation, and other downstream process and material-handling units. This capability has allowed IES to handle multivariable simulations across the mine value chain, including pre-concentration and in-pit size reduction, and modify the process simultaneously.

By Paul Piercy

Bougainville Copper Limited operates a porphyry copper mine in Papua New Guinea. The waste dumps will contain 400 to 500 million tomes of rock at the end of nine life. The paper describes investigations carried out over a period of en years and highlights the problems associated with waste lump leaching in a tropical and seismic active region. Aspects discussed include mineralogy, chemical reaction, leaching rates, microbiological activity, dump stability, dump structures, effects of tropical conditions, seismic activity and topography.

Jan 1, 1981

Water and wind erosion of toxic zinc and lead smelter waste is one of the most urgent environmental problems to be solved in the Silesia region of Poland. Over 87 x 106 Mg of various mining wastes were disposed of in uncontrolled piles leading to soil, water, and air pollution in highly populated areas. Welz and Doerschel process Pb/Zn smelter wastes were stabilized in the summer of 1994 by application of heavy loads of CaCO3 (30 Mg/ha), CaO (1.5 -15 Mg/ha), and municipal biosolids (150 -300 Mg/ha), followed by seeding with a mixture of acid-and salt-tolerant grass species selected in a pot experiment. Vegetation was successfully established on 85% of the Welz material demonstration plot area (0.5 ha), even though it was initially high in water-soluble Zn, Pb, and Cd ranging from 0.4 to 1311,0.1 to 5.8, and 0.05 to 55 mg/kg, respectively. Standing biomass averaged 3.3 Mg/ha on the stabilized Welz waste zone by the end of the third growing season (1997). The revegetation of much of the Doerschel material area failed initially because of extremely high salinity (16 dS m-1), high content of water soluble metals (Cd in particular), and heavy compaction. The area was capped (15 cm) with waste lime and retreated with bio-solids (300 Mg/ha) in 1995, and standing biomass averaged 2.9 Mg/ha in the fall of 1997. The observed plant response to bio-solids and lime indicates this approach to be an environmentally beneficial technology as compared to the traditional methods utilizing topsoil covers.

Jan 1, 1999

By Brenton Cook, Nate Long, Larry Applegate, Aaron K. McCain

"The Northgate Link Extension project is the third phase of the Sound Transit master plan to extend light rail throughout the greater Seattle metropolitan area. When completed, the Northgate Link Extension will extend the existing light rail system north by about 7 km (4.3 miles) from the University of Washington to the Northgate neighborhood. A general overview of the project alignment is provided as Fig. 1. The project was funded by a combination of federal grants and allocations from local taxes. The general contractor on the project was JCM Northlink LLC (JCM), a joint venture between Jay Dee Contractors, Frank Coluccio Construction Company and Michels Corp. SoilFreeze, Inc. was retained as a subcontractor to provide ground freezing design and construction services.The project involved the construction of two parallel 5.5-m, 25-cm (18-ft, 10-in.) (inside) diameter tunnels using earth pressure balance (EPB) tunnel boring machines (TBM) and precast segmental concrete tunnel liners. The two tunnels maintained roughly the same elevation along the alignment and were spaced roughly 12 m (40 ft) apart (centerline to centerline). A total of 23 cross-passages connecting the two tunnels were included at approximate 244-m (800-ft) intervals. Cross passage excavations were elliptical in shape with dimensions of approximately 5.6 m (18.5 ft) in height and 5.3 m (17 ft) in width. The cross-passages were 5.8 to 6.1 m (19 to 20 ft) long as measured between the exterior of the tunnels at springline elevation. Cross passages were intentionally located directly beneath public right-of-ways thus avoiding buildings. Many of the cross passages were located beneath narrow roads in residential neighborhoods with mature vegetation, existing utility structures and piping and limited parking areas. Excavation and support for each cross passage was completed using the sequential excavation method (SEM).The subsurface soil and ground water conditions at the cross-passage locations were described in the Northgate Link Geotechnical Baseline Report (GBR) prepared by Jacobs Associates and the Northgate Link Geotechnical Data Report (GDR) prepared by Shannon and Wilson, Inc. Soils along the project alignment were glacially overridden and characterized as very dense or hard. Subsurface soils consisted of cohesionless sand and gravel (CSG), cohesionless silt and fine sand (CSF), cohesive clay and silt (CCS) and till and till-like deposits (TLD)."

Dec 1, 2018

By J. P. De Carvalho, R. Dimitrakopoulos

An actor-critic reinforcement learning approach is presented to improve the production of an industrial mining complex by defining shovel allocation and adapting the short-term plan given grade-control decisions. Blasthole data updates the simulated orebody models, which are input into a stochastic grade-control method based on a spatially constrained clustering approach that minimizes the profit-loss function. These aspects are embedded in a discrete-event simulator that defines the material flow from faces to processors. A case study at a copper mining complex shows the methods’ ability to adapt to new information, improving the quality of the material feed and increasing cash flow by 23% compared to a baseline case.

Jun 25, 2023

By R. S. Datta

Regulations on sulfur emissions have caused the electric utilities to evaluate various methods of meeting them. Low-sulfur, low-volatile coals can be burned alone or blended with high-volatile? coals. This option may be a cost-effective alternative to the installation of scrubbers on coal-fired combustion systems. In some blending applications, problems may be encountered because the low sulfur content and high calorific value of the low-volatile or other clean coal allow it to economically upgrade extremely poor quality coal. While this is done to meet specification purposes, actual boiler performance may be dominated by the poorer quality coal. Thus, the reputation of the low-volatile or other clean coal suffers. As a result of laboratory and full scale testing, conducted over the last five years, a model has been developed to evaluate the relative combustion characteristics of various coals and coal blends. A database for different coals has been gathered. This paper presents the model and shows how power plants and coal mine personnel can use it to evaluate their coals from different sources. It can be used to blend two or more coals from different sources so that thee blended coal has flame stability characteristics which are similar to those of the baseline coal.

Jan 1, 1991

By Dan Nilsson

The Luossavaara "Research Mine" is the First large, offensive effort in mining research conducted by the Swedish state. Over a 5-year period, 1981-1985, the Swedish Mining Research Foundation works in the "Research Mine" on the development of mining systems and equipment. The purpose is to bolster the competitive strength of the Swedish mining and mining equipment industry. The previosly abandoned Luossavaara mine in Kiruna, in northern Sweden, has been reopened especially For the project. Ore is mined and sold during the course of the research project. The income from the sales covers a large portion of the costs for teh research.

Jan 1, 1985

By C. H. Pitt

A jet slurry apparatus has been constructed to test corrosive/erosive wear properties of grinding ball metal. Plain high carbon steel heat treated to a hardness of about 60 RC was used. Slurries of quartz and chalcopyrite ore concentrate were used as the jetting media. Weight loss due to pure corrosion was determined by the linear polarization technique and weight loss due to pure erosion was determined by jetting while cathodically protecting the sample. By comparing the total weight loss with the sum of the weight losses from pure corrosion and pure errosion it was found that there was a synergistic effect between corrosion and erosive wear. Erosive wear rates are given as a function of pH and mineral type.

Jan 1, 1984

By M. Fig, J. Brune, C. Strebinger, G. Bogin

"A fundamental understanding of flame propagation characteristics through and around obstacles is needed to accurately model methane driven longwall coal mine explosions originating or propagating in the gob. Experimental investigations of methane flames in horizontal cylindrical reactors with simulated gob (i.e. rock piles) were carried out alongside coupled Computational Fluid Dynamics (CFD) and combustion simulations. Stoichiometric methane-air mixtures were ignited in semi-open reactor vessels of 5cm, 9.5cm and 71cm diameter, all with a fixed length to diameter (L/D) ratio of 8.6. This was done both with empty reactors and also with a rock pile placed at the open end of the reactor. The rock pile length to reactor length ratio was fixed at 0.3, and the rock pile height to reactor diameter ratio was fixed at 0.33 for all reactors. The smaller two reactor experiments were modeled with ANSYS Fluent in 2D. Experimental results indicate that for this geometry a similar acceleration mode occurs across scales: that the flame speeds up an average of 40% as it passes over a rock pile with this profile. The model is able to capture several important features of the experimental results, including the significant increase in velocity, the speedup ahead of the rock pile, and the leveling off of the empty tube flame front propagation velocity. INTRODUCTION Explosions in underground coal mines are among the largest industrial explosions, known to result in the rapid combustion of 20m3 of fuel gas or more [1,2] Coal beds hold methane gas under pressure, and when the pressure is relieved through mining activity some of this methane is released. The methane then mixes with ventilation air and, if not sufficiently diluted, may form a combustible mixture, which may result in an explosion. Several large coal mine explosions have occurred around the world recently. These include the 2014 Soma Mine disaster in Turkey that killed 301 people [3], and the 2009 Heilongjiang Mine explosion in China that killed 108 [4]. Other recent mine explosions, including the 2010 disaster at the Upper Big Branch mine that caused 29 fatalities [5], have demonstrated that explosive gases can accumulate and ignite within and around the gob area of a longwall coal mine and then expand into the active mining face and nearby areas, endangering workers and equipment. If enough combustible gas is involved, the initial flame can accelerate, eventually transitioning from deflagration to detonation [6]. Researchers are developing a fundamental understanding of the evolution of the explosion process from the laminar kernel to the fully turbulent regime, and its propagation through obstacles such as those found in the gob. Researchers also studied the initial development of methane flames and the potential for the development of a detonation."

Jan 1, 2018