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By W. J. Dolinar

The U.S. Bureau of Mines implemented the Fe2+ /Fe3+-SO2 anode reaction in a Cu electrowinning cell with full-size electrodes. Electrowinning was conducted using industrial electrolyte at 258 A/m2 (24 A/ft2) and 40 'C. Manifold injection of electrolyte provided circulation between the electrodes. Five-day operation using an optimized manifold gave an average cell voltage of 0.94 V at 89% current efficiency, which amounted to an energy savings of 2.82 MJ/kg (0.355 kW-hr/lb) compared to conventional electrowinning. Acid misting was completely eliminated, and SO2 concentration 23 cm (9 in.) above the cell averaged 0.06 ppm.

Jan 1, 1995

By Robert Charles Alfred

Evolution is continuing in the field of rock drilling, Campbell Limestone Company is experimenting in the higher air pressure phase of drilling, It has been determined that there is a definite relationship between Air Pressure, Penetration Rate, Bit & Tool Wear and Life, In our drilling we have determined that &e higher air pressure gives a better penetration rate with less bit wear per foot. Drilling with 180 to 200 PSI air pressure, instead of 100 PSI for air and/or churn drills, has decreased our primary costs by approximately one half.

Jan 1, 1963

By Brett P. Spigarelli

To meet the growing need for CO2 capture and storage technology, Michigan Technological University is researching CO2 capture and storage using alkali solutions1. Without implementing emission controls, world energy emissions will rise from 29.7 billion t in 2007 to 42.4 billion t in 2035. The first objective of the project was to determine the optimal amount of alkali in solution for CO2 absorption. This was accomplished using theoretical equilibrium calculations and experimental absorption data for alkali solutions of 1, 2, 3, 4 and 5 weight %. As the % alkali in solution increased, so, too, did the ionic strength of the solution. Theoretical calculations took into account the effect increasing ionic strength will have on the solubility of gaseous CO2. The calculations assumed negligible formation of H2CO3, constant temperature and constant pressure. In the experimental setup, a 16% CO2 /balance air gas mixture was bubbled through an Erlenmeyer flask filled with an alkali solution. The gas exiting the flask was fed to a gas analyzer to record the % CO2 in the exhaust gas stream. The % CO2 absorbed was taken as the % CO2 in the exhaust gas minus the % CO2 in the feed. Theoretical calculations found that as the % alkali in solution increases, the solubility of CO2 decreases. This was verified by experimental data, which found that a 2% alkali solution, by weight, was the ideal solution for CO2 absorption. Current research is focused on using the 2% alkali solution for permanent storage of CO2 via mineral carbonation to produce a value-added product.

May 1, 2012

By R. H. King

Recently, the North American mining industry experienced a severe recession, forcing managers to take dramatic steps to cut costs and compete in the difficult international market. Some of these steps were closing mines, reducing work forces, renegotiating wage agreements, and purchasing the most productive equipment. Managers are now looking beyond these traditional avenues and are focusing more on advanced technology. In the present environment, it is essential that mine operators obtain the maximum use of capital expended on equipment. However, mine workers do not obtain maximum efficiency or productivity from equipment because the adverse and hazardous mine environment impedes human performance. Also, the efficient use of large, complex machines calls for levels of precision that many times are beyond the capability of even highly trained miners. A possible solution to this problem is a machine that mines without operators - autonomous mining machines. However, numerous problems confront researchers who are attempting to develop such equipment. Some mining tasks are not always composed of a series of cyclic motions readily performed by factory floor robots. In addition, mining takes place in the geological environment where conditions are highly variable and unpredictable. As a result, these machines must be able to sense and adapt to variations in operating tasks and environment. Considerable autonomous vehicle research has been completed, especially for defense. However, autonomous vehicle (AV) technology has not advanced to practical application yet (King, 1988) and mining research is necessary in areas: representing mining specific knowledge; •analyzing and reasoning about sensor data in the mining environment; and •discovering completely new mining methods or new approaches to existing methods that become apparent when we remove the constraints imposed by the necessity of human operators. A specific machine, the LHD, can be used to show the problems for researchers who are attempting to develop autonomous machines for mining. This author chose the LHD because it can borrow concepts developed for autonomous navigation by military programs. But considerable mining research is also required. Furthermore, studies done at the Henderson mine, in Colorado, show autonomous LHD 's promise cost and safety benefits (King, 1988). At Henderson, LHDs load ore from draw points, tram to an ore pass, dump and return, or switch to another draw point. An autonomous LHD must sense vehicle position along the route, relate sensor data to stored-map information, to determine location, follow drift center lines, plan paths between dump position and initiate appropriate control commands, sense vehicle operating status and vehicle health, key on features or targets for special tasks like high speed turns, perform end of travel tasks (loading and dumping), and detect and avoid obstacles. These goals are similar to those for shuttle cars, trucks, and front-end loaders. Therefore, much of the technology is transferable. Each Henderson LHD extracts six to 40 dippers from each of a series of draw points. The LHD transports the ore to an ore pass within 55 m (180 ft) of the draw point, making the longest round trip 110 m (360 ft). The LHDs have very fast hydraulic dumping and loading systems that reduce the round trip cycle to less than one minute. Even though the LHD is capable of 500 trips per shift, the average production is 300 dippers. Man trip and lunch reduce available operating time to 6.5 hours per shift. Mucking difficulties (setting large boulders aside), operator breaks for activities like talking shop, and cleaning and smoothing roads further reduce operating time. Supervised autonomy can reduce the number of operating units by increasing operating time per shift since computer controlled machines can operate during lunch and between shifts and reduce operator errors. If dippers per shift increase from 300 to 350 (long-range goals are 500 dippers per shift), constant production requires only 10 operating LHDs and two spares. Manpower requirements drop from 24 to four by controlling five machines from one workstation. A review of technology available from the Autonomous Land Vehicle, the Advanced Ground Vehicle Technology, the Ground Surveillance Robot, and other programs, show the following differences between others work and mining industry needs: •If we focus initially on mobile haulage vehicles, we can navigate from a map. We do not need to explore. •We can modify the environment to reduce the navigation requirements. •We have a harsher environment than any of the research programs have encountered. •Our equipment must operate faster and more precisely than present AVs. •Our equipment must operate reliably over long periods of time. •We must have better onboard machine health monitoring and diagnostics. •The AV programs do not address geosensing. •The major AV programs are not cost-effective. For example, we cannot afford the computer power for robust image processing, yet. To computer control an LHD, we must replace the guidance and monitoring skills of experienced operators with sensors, computing hardware, interfaces, and several software mod¬ules. Experienced operators avoid collisions and load efficiently in piles that may contain oversize muck. Collision avoidance without an operator requires sensing all obstacles in the draw

Jan 1, 1991

By D. J. Torpy

With copper at its host depressed price in several years, producers are looking at every opportunity to cut costs in order to continue operating. Some of the measures that have been applied by different companies include reduction in manpower, high grading, and in some cases partial shutdowns. The most beneficial cost cutting measure implemented by Southern Peru Copper Corporation was to steepen the slope of the final pit limit from a conservative 37 degrees to an average of 48 degrees. By doing so, substantial cash outlays were saved. Southern Peru Copper Corporation (SPCC) operates two open pit copper mines and concentrators in the southern part of Peru, about 150 kilometers from the Chilean bordar. The Toquepala Mine went into production in 1960 and the Cuajone Mine in 1976. Both mines use shovel, truck and train operations. The trains, which haul ore to the crusher or waste to the dumps, are loaded either directly by shovels or by a transfer system. The Toquepala Concentrator treats an average of 43,000 tons per day and the Cuajone Concentrator an average of 55,000 tons per day. Concentrates are shipped via a 200 kilometer railroad to the port city of Ilo where the SPCC smelter is located. The annual production in the smelter from both mines is 290,000 tons of blister copper.

Jan 1, 1987

By A. W. Khair

This paper presents an engineering approach to solve a complex ground control problem at reduced cost, allowing the mine to be operated safely and economically. The mine has experienced serious and complicated cutter roof problem in the entries. This cutler roof problem has delayed the advance of the entry development considerably and cost of these entries is very high due to the requirement of very heavy artificial supports. The analysis includes assessment of the cause of cutter roof and step by step action taken to improve the entry condition through appropriate longwall panel entry design and roof support system. The approach for solving the problem was two-fold: 1) to apply yield pillar concept in order to reduce the effects of in-situ horizontal stress in the roof strata and 2) to find an effective way to reinforce the roof strata and to support the fractured roof and avoid caving.

Jan 1, 1990

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 Yeonuk Choi, Patrick R. Taylor, Lyle Cunningham

Laboratory experiments have been performed to evaluate the potential for metal removal and recovery from river bed tailings by ferric chloride leaching. The lead, zinc, silver and other metals in the river bed occur due to the old method of dumping mill tailings into rivers. This was practiced prior to the introduction of tailings impoundments. The effects of the leaching method, leaching time, pulp density, ferric chloride concentration, and leaching temperature on the rates and recoveries of lead, zinc and silver were studied. The effects of pulp density and leaching temperature were significant on the extraction rates of lead, zinc and silver. The lead content in the leached tailing was reduced to 0.023 percent, when using an 353O K leaching temperature and 0.384 g of FeC13/1 g of sample.

Jan 1, 1992

To maintain its brand position in the competitive market of mining equipment, the Volvo Construction Equipment (Volvo CE) engineers were challenged to develop top-performing wheel loaders and articulated haulers even faster than before. To start, this meant reducing prototype test cycles by two-thirds. The final goal? Chopping in half the virtual prototyping time in early design phases. Creating a unified co-simulation solution In this ground-breaking project, the Volvo Construction Equipment design team in Eskilstuna, Sweden, replaced its piecemeal department-by-department process with a single solution based on LMS Imagine.Lab AMESim. With one unified model, they could simulate the behavior of four major vehicle subsystems in wheel loaders and articulated haulers: hydraulics, powertrain, thermal management and the actual driver. Subsystem models exchanged data seamlessly.

Jan 1, 2011

Automated drilling in surface mines is here, it?s successful, and it?s already at work in mines around the globe. Coal, copper, iron and gold mines in large mining countries such as Canada, Australia, South Africa, the United States and Chile are meeting mining objectives previously ruled out as unattainable. Pit Viper automation enables operators to accomplish more objectives safely. Operator assist functions like AutoLevel, AutoDrill, Auto Rod Changer and multi-rig teleremote control are a few of the features mines are using to gain consistent, sustainable productivity.

By J. J. Lewis

The chapter describes how several OR techniques assisted the planning of a major new UR project. A computer system was developed to analyze reserves distribution and potential of possible underground layouts, to assist in choosing the location and size of access points. Manpower requirements of each proposed working plan were assessed and matched with the potential recruitment of skilled and unskilled labor. Computer simulations were used to determine the optimum capacity for coal preparation plant and surface bunkerage. For the overall assessment of robustness, financial modelling and risk analysis techniques were adapted to the special requirements of new mines.

Jan 1, 1979

By M. T. Ityokumbul

Flotation columns and their variations are increasingly replacing conventional cells in mineral processing circuitry. While the operational characteristics of columns differ from those of conventional cells, the same scale-up methodologies are being employed in design. This practice may be attributed to poor understanding of the factors controlling throughput. The use of tall flotation columns is frequently justified on the requirement for increased particle residence time. It is shown that longer particle residence times in the column cell alone do not translate into increased recoveries. Throughput data from several industrial flotation column installations is presented. An attempt at using dimensional analysis to provide scale-up methodology for the factors controlling column throughput is made.

Jan 1, 1995

By Jonathan G. Price

Silver-copper-lead deposlts in Precambrian, Permian, and Cretaceous red-bed sequences near Van Horn, Texas, have the following features In common: (1) mineralization controlled by steeply dipping fractures in sandstones, (2) lack of ore In overlying and interbedded limestones, (3) absence of igneous intrusions, (4) sulfide ores without typical hydrothermal gangue minerals, and (5) associated arsenic, molybdenum, zinc, and cadmium but not gold. Ore was probably deposited along fractures by reaction between low-temperature, oxidizing, metal-rich ground waters and sulfide-bearing waters or rocks. Detailed mapping and studies of fracture patterns indicate that mineralization occurred during Basin and Range extensional deformation, thereby postdating major Trans-Pecos igneous activity.

Jan 1, 1983

By N. Nemeth

The filter is an apparatus designed to hold the filter medium. At such a medium takes place the entire liquid-solid or gas-solid separation process. Hence, the medium is really the essence of filtration. Yet, the medium, an originally clean porous substance with trapped solids in it, is perhaps the most neglected part of filtration research. Basically three problems prevail at the medium: 1) Penetration of solids and their blinding of the medium and the influence of such blinding on the resistance to flow. ii) The behavior of the medium in long term repetitive filtration. iii) The filter effect phenomenon whereby the flow rate on filtering an apparently clear liquid through a medium decreases with time. This study undertakes to investigate these fundamental processes.

Jan 1, 1968

By S. Chander

The effect of sample storage in argon and in air on kinetics of oxidation of pyrite from a coal source was studied using accelerated weathering test in laboratory columns. Prior to the weathering tests the samples were crushed, ground, and stored for various time periods in argon and air. The results showed a dramatic difference in the rate of oxidation of the aged samples. The differences were interpreted based on the hypothesis that the aging of pyrite led to the formation of surface coatings which changed with time. The significance of these results in pyrite/reagent interactions in flotation and in evaluating the acid mine drainage potential of pyritic waste materials is discussed.

Jan 1, 1993

By Justin Jensen, Luis Moya, Jose Carlos Durazo, William Szolga, Tyler McCallum, Tim Doubleday

Sulfuric acid mist is an undesired by-product of the copper electrowinning process, caused by oxygen evolution at the anode which entrains droplets of the acidic copper electrolyte solution. As the oxygen moves to the surface of the cell, these droplets become aerosolized resulting in acid mist. The addition of chemical anti-misting agents to the copper electrolyte is a common mitigation technique. This paper details Syensqo’s laboratory development of a new environmentally friendly acid mist suppressant, ACORGA® EW98. The product exhibits excellent acid mist suppression and it is fully compatible with the adjacent solvent extraction process. Lab and pilot test results are reviewed ahead of future planned industrial trial testing.

Feb 1, 2025

By William Gleason

"Mining roots run deep in Glenrock, WY, a town that was founded in part, because of the coal mining that began in the late 1800s. But that rich history also now threatens large parts of the town that were built over the top of the mines. Like many towns in the Western United States, mining is a proud part of the historical fabric and heritage of the town, but the legacy issues from past mining activities continue to present challenges to modern-day engineers.In the case of Glenrock, a small town about 40 km (25 miles) east of Casper, it is flooding from a century of water that has accumulated in the down geologic dip of the furthest northeastern extent of 87 ha (217 acres) of mine workings that has made the town susceptible to sinkholes and other issues (Fig. 1).Full commercial coal mining production began in Glenrock in 1887 during the development of the Fremont, Elkhorn and Missouri Valley railway. Due to poor overlying roof rock and continuous flooding within Glenrock, Mines No. 1 and 2 were fully closed in 1909. During its history, an estimated 87 ha (217 acres) were mined with 50 to 60 percent extraction ratio within the eastern town limits through room-and-pillar mining. It is estimated that the mines produced 22 kt/a (25,000 stpy) during their lifetime. A century later, the water pressure built up in the northeastern most portion of the mine has created serious concerns for residents.In 2016, the Wyoming Department of Environmental Quality’s Abandoned Mine Lands Divisions (AML) investigated a number of subsidence events in the town including sinkholes following heavy precipitation. The AML investigations confirmed that most events were related to the previous mining in the area.Mitigation efforts on the mines were done in the 1980s and 1990s, but the problems in the town and in a nearby subdivision persisted, leading the AML to search for alternative solutions."

Nov 1, 2019

By Kenneth S. Johnson

Oklahoma is the only; state in the nation that is currently producing iodine. The iodine is extracted from iodine-rich natural brines being pumped from deep wells drilled into Pennsylvanian sandstones in the Anadarko basin of northwestern Oklahoma. Woodward Iodine Corp., started in 1977, was the first plant in the United States built for iodine recovery since the 1930s. At present, three companies are operating four iodine-producing facilities in northwestern Oklahoma. The combined production of these facilities, 1,321,000 kg in 1997, is about 26% of the U.S. annual consumption. Iodine is present in concentrations ranging from less than 100 ppm (parts per million) to as much as 1,560 ppm in brines in various Paleozoic strata in the subsurface of northwestern Oklahoma; these concentrations are exceptionally high, and are well above those of any other known brines in the world. Strata with the highest iodine content in the area (Mississippian limestones) have low permeabilities, and thus would yield only small amounts of brine. On the other hand, the lower Morrow sandstones (Lower Pennsylvanian) have a relatively high permeability and are capable of yielding large quantities of brine that average 300-350 ppm iodine. The Morrow brine reservoir was deposited in shallow-water-marine and intertidal-shelf environments and now is buried 6,000-10,000 ft below the land surface. Production is localized to Morrow channel deposits confined to an Early Pennsylvanian paleovalley that is 1-2 mi wide, is about 70 mi long, and is referred to informally as the "Woodward trench." All three companies are producing iodine-rich brines from Morrow sandstones in three different parts of the Woodward paleovalley, and one of the companies also is extracting iodine from oil-field brines coming from several petroleum reservoirs near Dover, about 80 mi east of Woodward. The basic extraction method employed by Woodward Iodine Corp. was used in Louisiana and California operations in the late 1920s. This method is commonly called the air-stripping process. Lower Morrow brine containing dissolved sodium iodide is pumped to the plant through a series of pipelines, where by-product natural gas is separated and processed. The brine is then acidified and subsequently oxidized with chlorine to convert the iodide to iodine. The iodine is air stripped and reabsorbed with sulfur dioxide and water, converting it to hydriodic acid, or process liquor. The process liquor is then processed, using chlorine once again, to crystallize the iodine as a solid. This is then melted and frozen to form a solid product, which is packaged in 110-lb (50-kg) drums and shipped to end users throughout the world.

Jan 1, 1999

By A. L. Mular

In order to simulate a grinding circuit, it is necessary to obtain valid mathematical models of the grinding mills and classifiers in the circuit. Several models of grinding mills Ova been proposed 1,2,3 and models of cyclone classifiers are available 4,5. Those models developed by Lynch et. al. 3,5 have been tested in the plant, so that some degree of reliability can be placed on them. Because of this, it is reasonable to assume that the Lynch models will apply for a given circuit, and then to test this assumption. Empirical modifications are made as necessary for a given situation. Usually, valid simulation models can be modified slightly to provide control models6,7. The purpose of this paper is to describe the results of an approach taken by Mular8 to obtain the Lynch models of parallel cyclone classifiers being used in the A-circuit of the new Strathcona Mill***.This was one of the projects undertaken by the fourth year Metallurgical Engineering Class of 1969, Queen's University, Kingston, Ontario, Canada, as part of their process design course which cooperates closely with the Canadian metallurgical industry.

Jan 1, 1970

By Dennis D. Fischer

The second underground coal gasification experiment conducted by ERDA's Laramie Energy Research Center at a site near Hanna, Wyoming, was completed on July 30, 1976. During the experiment production reached 0.32 Mm 3/d (12 Mft3/d) of 6.9 MJ/m3 gas (175 Btu/ft 3 ). Approximately 6100 tonne (6700 ton) of coal were gasified during the experiment. Energy return ratios of 4.5 to 5.3, cold gas - thermal efficiencies of 76 to 89 percent, and overall process efficiencies of 65 to 74 percent were achieved during the second Hanna experiment. This paper describes the experiment and the results obtained with emphasis given to the determination of the energy recovered relative to energy consumed in conducting the test. Data from this determination are compared with previously published data from the first test conducted at Hanna during 1973-1974.

Jan 1, 1977