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By I. Farr, M. R. Mock, J. C. Robison

"HPAL and POX autoclave vapor-space gasses are vented through an autoclave PCV (Pressure Control Valve). The downstream steam-born mist of liquid droplets and solid particles travels in excess of 1000 m/s with megawatts of kinetic power at temperatures up to 160 C. The characteristics of downstream states often result in problems with corrosion, erosion, noise and vibration. Comprehension of those and related characteristics aids in improved pressure control, overpressure control and autoclave level control. We introduce compressible multiphase flow concepts and constructs germane to such flow including choked flow, continuous phase change, shock waves and supersonic flow plumes. Flow modeling based on first principles quantitatively predicts such flows providing a tool for component sizing and a method to estimate effects of water injection on flow. Insight deduced from modeling aids in mitigation of afore mentioned problems of which we share some from-site examples.INTRODUCTION First principles related to fluid thermodynamics and compressible flow have been employed akin to their application in the rocket industry. We will present the results of the application of those principles conceptually and authentically without mathematical rigour while using language of the pertinent disciplines. The autoclave (AC) vapor space over the slurry of a POX (Pressure Oxidation) or HPAL (High-Pressure Acid Leach) system (depicted in Figure 1) is vented via a PCV (pressure control valve) followed by certain ducting, and perhaps a nozzle, before exiting at atmospheric (typically) pressure. As indicated by its name the PCV controls the AC pressure as the flow control component of a pressure control loop."

Jan 1, 2017

By C. H. Buck, A. J. Taylor

"In 2015 Vale’s Clarabelle Mill began the process change to enable a higher degree of Cu separation. The flowsheet modification was part of a complete divisional flowsheet change being implemented in Vale’s Sudbury Operations. This paper will centre on some of the Operational Readiness (OR) work, culminating in the commissioning of the circuit in March 2017. The emphasis will be on the implementation of an integrated test plan to prepare for the process flow change through the mill.BackgroundClarabelle Mill (CBM) began making a saleable Cu concentrate in 2006 with the installation of the Cu separation circuit. Typical separation rate was 35-40% of Cu in feed reporting to Cu concentrate based on a target Ni concentrate Cu:Ni target of 0.7-0.8. The remainder of the recovered Cu (55-60%) reported to Ni concentrate and was smelted through the Copper Cliff Smelter.In 2013 a capital project, Surface Facility Upgrade (SFU), was implemented to focus on matching the surface plants capacities with the future mine plan to maximize revenues. This was to be achieved by redistributing the metal flow, specifically Cu, through CBM to increase metal unit content through the Smelter. The amount of redistribution of Cu was determined to be based on maintaining a stable Cu to Ni ratio (Cu:Ni) in the Ni concentrate.The change in Cu:Ni ratio in the Ni concentrate would affect the Sudbury divisional flowsheet, and required process changes across the all of the surface plants. The detail that surrounds the flowsheet changes as a whole will not be discussed, but the outcome of the decisions plays a large role in the operational readiness interactions between the mill, its suppliers and its downstream customers."

Jan 1, 2018

By J. Janeson

Wall control at the Pipe Open Pit is of primary importance in ensuring the long-term stability of the operation, while keeping costs to a minimum. Blasting techniques have been adapted to the variations in competence and structure of the wall rocks. A portion of the perimeter wall is being developed in incompetent peridotite . A recent change in pit slope design provides a wide safety berm on alternate benches. A support program which consists of pinning the crests of wide berms with vertical reinforced concrete dowels and horizontal bolting of walls shows evidence of increasing the stability of the pit walls. This paper describes the blasting and support techniques which are contributing to successful wall control in the Pipe operation.

Jan 1, 1979

By B. Voyzelle

The deterioration of highway and bridge infrastructure has received considerable attention in recent years because of the billions of dollars needed for repair and rehabilitation. A major factor contributing to this problem is the corrosion of steel reinforcement. Reinforcing steels with good corrosion resistance and relatively low price are therefore essential for maintenance, cost reduction and service-life extension of the steel-reinforced structures. This article describes the development of low-alloying steels that offers good corrosion resistance with reasonably low cost. Topics include steel microstructures, mechanical properties, corrosion performance, industrial applications and economic aspects.

Jan 1, 2005

By S. S. Al-Thyabat, A. M. Ghrair

"Printed circuit board (PCB) is the main part of any electric or electronic device, providing mechanical support and electric connection for the board eclectic components such as capacitors, resistors, diodes etc. PCB consists of non-conductive substrate overlaid with one or more layers of copper sheets. They also contain appreciable amounts of base metals (copper, nickel, tine, and aluminum) and precious metals (gold, silver, and rare earth elements (REE)) which end up in the landfill at the PCB end-of-life.PCB recycling E-waste in general is a profitable business; many valuable raw materials, precious and base metals, can be extracted with high purity. Approximately, one metric tonne of PCBs may contain 80-1500 g of gold and 160–210 kg of copper. The precious metals recovered from PCBs occur at concentrations higher than commercially mined minerals. Also PCB recycling is very important to our environment since many heavy metals (e.g. lead) may be leached from the landfills to the underground reservoirs. In Jordan, however, the work conducted on E-waste and PCB recycling in particular is limited; currently most of the E-waste is either exported or dumped in the landfill.In this work, a combination of physical (magnetic separation), physicochemical (flotation), and chemical methods (leaching) were used to compare metals concentrations in leach liquors produced from a concentrates resulted from a combination of these methods. It was found the leach liquor of the magnetic fraction of the PCB coarse size gave the highest concentration of Fe, Al, and Ni while concentration of Cu was higher in leach liquor of nonmagnetic sink fraction. On the other hand, metals concentration almost similar for both sink and float of the fine size fractions, indicating even distribution of metals concentrations in the fine size fractions."

Jan 1, 2016

By John D. Campbell

Alberta Plains coals exhibit an almost rectilinear system of vertical fracturing called "cleat", which is best traced by mapping true bearings of underground coal mine rooms. The cleat pattern is approximately conformable with a pattern of surficial features and a pattern of bedrock jointing in the Alberta Plains, and with the trend of the Rocky Mountain Trench, but not with the distribution pattern of coal rank nor with the trend of the eastern boundary of the Rocky Mountains and Foothills physiographic province. The processes resulting in cleat remain in doubt, but cleat is always of practical importance in extracting coal from deeply buried deposits.

Jan 1, 1979

By Steve T. Laflin

Since the beginning of the nuclear era, there has never been a commercial solution for the large quantities of depleted uranium hexafluoride generated from uranium enrichment. In the United States alone, there is already in excess of 1.6 billion pounds of DUF6 currently stored. INIS is constructing a commercial uranium processing and fluorine extraction facility. The INIS facility will convert depleted uranium hexafluoride and use it as feed material for the patented Fluorine Extraction Process to produce high purity fluoride gases and anhydrous hydrofluoric acid. The project will provide an environmentally friendly and commercially viable solution for DUF6 tails management.

Aug 1, 2010

By David Burchell

Duckbill mining is probably the simplest method of loading coal mechanically at the face in underground mines. It is a means of reducing the amount of physical labour required to produce a ton of coal. In effect, it is merely shaker conveyor mining brought up to date with the addition of a self-loading head or 'duckbill' on the end of the conveyor line. Any mechanical device used to load coal is a means of supplanting the human muscles as the medium for getting the coal off the floor into the transportation equipment. There can be no argument with the conclusion that a man can lift so much and no more. He can load more tons of coal on a low conveyor, because the lift is less, than he can in a pit car two, three, or even four feet high. Thus it follows that, if the lifting operation is entirely eliminated, the man should be able to produce even more coal. A mechanical operation is essentially a multiplication of physical strength. Although there are various ways in which coal can be loaded at the face by mechanical means, there is, perhaps, none more adaptable than shakers equipped with duckbills. This is particularly true for thin seams and in mines having heavy, tender top conditions which require close timbering. However, as we are discussing duckbill mining, we will make no further reference to any other type of equipment. The first, and to date the only, mine in eastern Canada to adopt a system of mechanical loading at the face is the Franklin mine of the Bras d'Or Coal Company, Ltd., at Bras d'Or, N.S. An experimental Goodman shaker conveyor with a self-loading head, or duckbill, was installed in this mine in 1940. Since that time other units have been placed in operation so that, today, this mine is completely mechanized. The method of operation 1s room-and-pillar. The operation is carried on in a 42-in. seam, which lies 420 feet beneath the Sydney Main or Harbour seam in the Sydney Mines basin. The slopes bear N.25 30'E., dip 10 per cent seaward, and are about 6,000 feet in length. The physical conditions of this seam do not make it particularly adaptable for complete mechanization as it contains a large amount of foreign material, such as clay intrusions or wash-outs and iron pyrites. These clay intrusions, known locally as 'troubles', vary in thickness from a few inches to as thick as eighteen feet and usually replace the coal to the full height of the seam.

Jan 1, 1947

By F. Channier

The paper provides the most recent information on the construction of the AP60 phase 1 plant of Jonquiere which is due to be commissioned and started up in the first quarter of 2013. HSE management on site by RTA, and cooperation with local equipment manufacturers and contractors of the Saguenay-Lac Saint Jean region are highlighted in this section. The AP60 phase 1 Jonquiere plant aims to demonstrate of the AP60 technology at an industrial scale and allows the further developments of the AP60 cell. The advantages of the AP60 cell technology in terms of productivity, power consumption and environmental footprint are also briefly presented in the paper.

Jan 1, 2011

By E. Lee Cameron

The old mine workings on four barite-fluorite veins of the Lake Ainslie district, Nova Scotia, were opened recently and channel sampled. The samples were then forwarded to the Ore Dressing Laboratories, Bureau of Mines, Ottawa, for chemical analyses. Following the analyses, the sample rejects were combined to form bulk samples, representing ore from each vein, for small-scale batch test work. Tonnage samples from the veins, for pilot mill testing, were submitted when requested by the Bureau. The results of the analyses on the channel samples showed that there are two grades of ore in the di strict, represented, for test purposes, by the Trout River vein and Johnson vein ores. Small-scale and pilot-plant test work was undertaken on both these ores. The Trout River ore is amenable co concentration but, because of the high-barite-co-fluorite-co-calcite ratio, a fluorite concentrate was not obtainable from the Johnson vein ore as received. However, Johnson ore blended in a 1 :1 ratio with Trout River ore gave a mill feed that was readily concentrated. The test work on these ores showed that the following concentrates are obtainable : (a) A barite concentrate, with a recovery of 85 to 95 per cent of the available barite, analysing 93 co 96 per cent BaS04, 4 co 6 per cent CaF,, and 0.5 co 2 per cent CaCO3. (b) A fluorite concentrate, with a recovery of 80 co 85 per cent of the available fluorite, analysing 94 to 97 per cent CaF, , 1 to 3 per cent BaSO., and 1 to 3 per cent CaCO3

Jan 1, 1945

By Gennaro Delisle

"Les Services TMG (Niobec) currently treat a niobium ore in the Chicoutimi area of Quebec. The mineral pyrochlore is present in a carbonatite deposit which assays 5% to 7% apatite.The ore is ground to minus 65 mesh and deslimed at 10 micrometres. Part of the carbonates are floated with a fatty acid emulsion and rejected to the tailings as a first step to ensure the proper conditions for the flotation of the pyrochlore concentrate. The carbonate concentrate is 65% minus 44 micrometres and is composed of dolomite, calcite, 22% apatite and a minor amount of silicates.A laboratory investigation was undertaken to determine the feasibility of extracting apatite from the carbonate concentrate. This led to the development of an economic flowsheet to produce high-grade apatite concentrate. The apatite is depressed with phosphoric acid, and the pH is adjusted at 4.8-5.0 with sulphuric acid. An additional amount of fatty acid is added to permit efficient flotation of the carbonates. 1n a second stage, the silicates left behind with the apatite concentrate can be removed by depressing the apatite with AIC3 while floating the silicates with a secondary amine.The results of the laboratory tests indicate the possibility of producing an apatite concentrate assaying 38.3% P2O5 (83.7% BPL) with a recovery of 66.2%. Pilot-plant tests undertaken at the concentrator yielded a concentrate of 34% P205 and recovery of 76%."

Jan 1, 1981

By Joseph Hirschi, Behrooz Abbasi, Harrold Gurley, Yoginder P. Chugh

"The research goal was to assess if analytical tool/s can be developed to quantify displacements around a geological fault as longwall face moves toward it and past it. A company was faced with crossing a 2-3 m (6-10 ft.) normal up-thrown fault in the development entries and the face while mining a 375 m (1,200 ft.) wide longwall face. A field monitoring and numerical modeling study was performed to develop data. Field measurements consisted of roof-to-floor convergence and rectangular rosettes in the immediate roof. Numerical modeling consisted of constructing a 3-D structural model using the FLAC3D software with the fault plane incorporated as ubiquitous joint. Based on analyses and field observations data, the coal company was informed of impending movements along the fault plane and likely impacts on the development entries. Additional stiff supports were installed in head gate entries around the stage loader and equipment about 60 m (200 ft.) outby of the longwall face (solid). As the longwall face approached the fault, predicted displacements were documented and manifested by severe loading on the installed supports.BACKGROUND AND STUDY OVERVIEWThis paper summarizes results of a cooperative study aimed at improving longwall mining operations in Illinois. More specifically, the study focused on: 1) In-mine measurements in development entries while mining ahead of and behind a faulted zone, 2) Making observations on stability of pillars and entries while mining through the fault, and 3) Developing simplified analytical structural models using FLAC3D to assess if predictive techniques can be developed to plan mining operations through fault zone. Available data on geometry of the fault with estimates of the cohesion and frictional parameters were used for modeling."

Jan 1, 2015

By P. Kostuik

"Recent interest in the pipeline transport of solid mate-als has been sparked by the idea that, in an inflationary onomy, pipeline costs are more stable than the costs of any other transport systems. Pipelines have proved over 1e years to be dependable, records indicate that main-•nance and operating costs are comparatively low, and 1eir amenability to automation is of considerable im->rtance.The concept of hydraulic hoisting of solids from under-round, or cross-country hydraulic transportation of con-~ntrates and ores, is currently of prime interest to the ining industry. In general, this paper deals with a preliminary investi-ation of energy losses incurred while transporting a rela-vely heavy, crushed mine product, namely magnetite, oth vertically and horizontally. The basis and validity of everal equations derived by other experimenters to com-ute these losses is discussed. A theoretical analysis of ydraulic hoi:,,ting is made, and, based upon test results, calculation of horsepower requirements for hoisting an re under a given set of conditions is presented. Results indicate that:n vertical transport, the friction head losses are identical to those of clear water, and the total energy requirement for hydraulic hoisting then becomes a function of height of lift, concentration and specific gravity of the solids being hoisted. .-In horizontal transport, friction head losses can be calculated with reasonable accuracy using Bonning-ton's correlation curve. Losses computed utilizing Durand's correlation (K = 85) result in estimates which are too low by 10 to 30 per cent, an<l those calculated using Newitt's correlation (K = 1,100, K = 66) give friction loss values which are too high by 10 to 30 per cent . . -The theoretical horsepower (RMS-hp.) required for hoisting hydraulically is approximately half of that required for conventional double-drum skip hoisting."

Jan 1, 1966

By H. S. Price, F. N. Kissell, R. C. McCulloch, J. C. Edwards

"The methane em1ss10n from deep coalbeds which are actively mined is a serious problem facing the mining industry today. Pinpointing the source of methane and predicting the emission of this gas from these coalbeds is necessary if preventive techniques are to be effectively used to control methane emission. In general, because most coalbeds have water associated with them, the system to be studied may be either single-phase (methane gas) or two-phase (methane and water). Because coal mine geometry is complex and the fluids have variable properties as functions of pressure and methane concentration, the differential equations describing the flow of methane and water are not amenable to analytic solution, but must be solved numerically using high-speed computers. This paper presents the development of such a complex mathematical model along with some preliminary applications of the model to methane emission from one- and two-dimensional coalbeds with and without water present."

Jan 1, 1973

By R. M. Lauer

OVER THE YEARS concentration of the Sullivan ore has become progressively more difficult as the ore has become increasingly refractory. The introduction of new reagents and changes in the flow of the concentrator have been and continue to be necessary in order to maintain and improve the efficiency of metal extraction. Prior to the completion of the pilot mill in 1957 ail new ideas were developed in laboratory equipment. If these were found to be promising, there was no alternative but to introduce them directly to the main mill flow in one step. When a major change was involved there was always the possibility of serious losses while the mill was being adjusted to the changed conditions. It proved difficult to determine whether these losses were the result of the changed procedure or of failure to adjust the flow to a change in the condition of the ore during the test. The pilot mill has provided a valuable intermediate step between the laboratory and the mill. It avoids the losses which occurred when unsuccessful full-scale tests were attempted, and conversely it provides assurance that full-scale flow changes can be made without serious hazard.

Jan 1, 1960

By Alexander Smith

"The Silver Standard mine is 6 miles by road northwest of New Hazelton, B.C., a small town on the northern line of the Canadian National Railways some l 75 miles northeast of Prince Rupert. The deposits lie on the western slope of Glen Mountain (elevation 2,100 feet), with the main adit, mill, and campsite at 1,300 feet. The deposits were found in 1910, shortly after the area had been swept by forest fire and during a period of prospecting activity spurred by the construction of the railway. Crude ore only was shipped until 1918, when a 50-ton gravity mill was built which operated until 1922. Gross value of production of this period, at present metal prices, was about $1,000,000.In 1947 the present company was formed and a 50-ton flotation mill installed. Production from 1948 to 1955 has been in excess of $10,000,000, and net smelter returns about two-thirds of this amount. More than 60 per cent of the production and 80 per cent of the profit have come from one vein, No. 6. On the 1,300-foot level this vein had an ore section 375 feet long and 2.5 feet wide, averaging 0.18 ounces gold, 85 ounces silver, 10 per cent lead, and 16 per cent zinc.The mine workings follow a simple pattern. A series of parallel veins, striking northeast and dipping southeast, are numbered from 0 to 12, starting at the northwest. They lie within a zone trending south 70 degrees east, and the distance between Nos. 0 and 12 veins is about one mile. Recently several cross-veins, dipping northeast, have been found between Nos. 8 and 12. They are apparently of the same type as the others, though they may not have the same structural controls. They could be an important new source of ore.The mine has been developed principally by crosscut adits at the 1,500- and 1,300-foot levels and a 510-foot shaft with levels at I, 150, 1,000, ·and 850 feet. Drifts and crosscuts total 17,000 feet, chiefly on Nos. I, 4, 6, 7, and 8 veins. The drifts are stoped by shrinkage, top shrinkage rill, cut-and-fill with resuing, or open stope methods. The mill produces a lead-silver-gold-copper concentrate and a zinc concentrate, with indicated recovery of more than 96 per cent (4)."

Jan 1, 1949

By Saravarim A.

"The aim in flotation systems is to control the grade and recovery of the product., numerical method or sampling and analysis is used to achieve this goal. Weakness of measuring instruments, lack of process knowledge, deficiencies in management and data processing in the control of flotation cells, has led the academic and industrial units to use numerical models. In this regard, using the results obtained from the experimental design carried out in the DTP line of Gol Gohar industrial and mining complex, a regression model was developed based on the analysis of variance. To present this model, after variance analysis of factors and interactions, all models were investigated and the final model was created based on 75% of the data. The model was tested with the remaining 25% of the data to confirm the goodness of the fit. The coefficient of determination for training and testing resulted 71% and 74%. Moreover, a feed forward back propagation neural network with different layers and neuron was used to model the results. The best network structure was 6-27-1 and the coefficient of determination for this network was 99% and 98% for training and test respectively. Given the complexity of neural network models and the relatively low accuracy of the regression model, neural network has a priority assuming we have access to a specialist. In addition, the results obtained from neural network can be used as expert systems to control and optimize the flotation cells.INTRODUCTIONThe primary objective of the flotation cell control is to maintain the product's (in this case tailing) recovery and grade, which represents the index for process efficiency and product quality. Continuous estimation of these indexes requires a significant amount of maintenance, and calibration of the continuous analyzers, in order to maintain an acceptable level of accuracy. Weakness of measurement equipment, lack of process knowledge and the general deficiency in management and processing of data in the flotation cell control, will lead industrial units to use smart methods such as mathematical models, regression and neural networks in near future (Panahi, Abdollahzadeh, & Sam, 2010). Artificial neural networks are inspired by the very complex structure of human brain in which millions of nerve cells solve problems or store information by communicating with each other. The duty of neural networks learning. It should be noted that learning in artificial neural networks is limited, and what is practically considered is the computing power of the network. A neural network consists of units called neurons, and has the capacity to handle a set of input data to produce a desired output data set. Each of these input and output data sets can be assumed as a vector (Soltanmohammadi & Noparast, 2006)."

Jan 1, 2016

By Marcin Ziemski

This paper reports on an energy efficiency analysis completed as part of a research project looking at energy reduction opportunities in minerals processing operations. The plant discussed is a gold production facility owned by Newmont Gold in the Tanami region of central Australia. Due to its remote location, lack of nearby gas pipeline or power grid, the operation has been completely dependent on diesel fuel for its electricity generation and transport needs. The mine and processing plant use electrical power at a rate of 12MW to 18MW, resulting in a monthly electricity cost of over US$1.5M. The high cost of diesel combined with an impending power generation capacity shortage drove Newmont to undertake the energy efficiency study. An energy audit of the plant showed opportunities for significant energy savings through the strategic use of waste heat, fuel replacement alternatives and renewable energy sources.

May 1, 2007

By Edouard Asselin, Tasawar Javed

This study was conducted as a part of ongoing work to characterize sulphide concentrate leach residues generated under CESL (Cominco Engineering Services Limited) and Vale pilot and demonstration plant medium temperature (150 °C) process conditions. Three different samples were analyzed. Derivative samples were prepared by extracting gypsum, sulphur and amorphous/poorly crystalline iron oxyhydroxide phases from the leach residues. Thermal behavior of the samples was studied by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) in the temperature range 25 to 800 °C in both air and nitrogen atmospheres, with XRD analyses both before and after heating. Thermal transformation temperatures for different iron oxides/oxyhydroxides present in hydrometallurgical leach residues vary over a wide range which suggests the variable crystallinity of the phases. Raman spectroscopic analysis was carried out to help identify the type of iron phases in the residues. Furthermore, hydroxylamine hydrochloride (HaHC) and oxalate extractions were used to compare the fractionation of the amorphous/poorly crystalline iron phases in the residues. Given the compositions of the residues, any thermal events in the temperature range of 200 °C to 480 °C were attributed to amorphous/poorly crystalline iron phases.

Jan 1, 2014

By Yoginder P. Chugh

This paper discusses design of sprays systems for dust control around a continuous miner (CM) in about 4.2 m (14 ft.) high mining areas with about 1.0 m to 2.0 m (3-6 ft.) of out-of-seam dilution mining. The challenges included low air volumes and velocity at the end of the line curtain, dust produced from out-of-seam dilution rock being very fine with 50% of the particles less than 10 micron, poor capture of aerosol through scrubber suction inlets, dust escaping through the sides of the loading pan in mining high areas, overloading of dust-laden air in the wet-scrubber, and dust rollback toward workers. The challenges were resolved through CFD modeling of airflows; improved line curtain installation, redesign and varying the spatial locations of spray systems as compared to low mining height areas. Water sprays on CM is the primary engineering control for dust control in coal mining. In 2010, the authors developed several spray system concepts for dust control (Chugh, Patwardhan, Gurley, & Hirschi (2009), Chugh & Gurley (2009), Chugh 2012). These included increased contact time between dust particles and water droplets, improved potential for the dust aerosol to be sucked in through suction inlets, and reduced dust-roll back to the operators and workers. CFD modeling was used to understand airflow patterns around mining areas and to identify spatial locations for sprays to minimize dust exposure of CM operator (CMO), haulage unit operator (HUO), and workers downwind of the operating CM in the last open crosscut (LOXC). Face area ventilation plays a key role in dilution and removal of dust generated by mining operations. High mining heights and large pillar sizes associated with longwall mining reduce the air volume reaching the face area to achieve good dust dilution.

Aug 1, 2013