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By Dennis E. Peterson

Land subsidence had been observed in recent years throughout the Southwest. Particular examples of this phenomenon that have gained wide publicity axe in the Long Beach and Central Valley areas of California and, the Houston area of Texas. Less well known is the fact that the land surface Is subsiding in many parts of Arizona, including the Phoenix area. The causes of this problem vary from place to place, as do also the rates of subsidence. In Houston it has been related to pumping water from artesian aquifers; in Long Beach to the development of oil fields; and in the Central Valley to both the lowering of artesian pressures in deep aquifers and the wetting of poorly consolidated surficial deposits. The mechanism by which subsidence occurs in southern Arizona, even though it can be correlated with the continued lowering of ground water levels, is not as apparent as in these other cases. It is the purpose of this paper to examine both the causes and affects of land subsidence in southern and central Arizona.

Jan 1, 1965

By B. S. Graves

Deep well disposal of selected industrial wastes has been proved feasible and acceptable in the New Orleans area by several industries including Shell Oil Company's Norco Refinery and Chemical Plant where three of the six successful disposal wells in this area are operating. Well design and procedures for restoration of capacity are based, in most cases, on the principles of brine injection developed by oil producers in South Louisiana. Geological formations in the Gulf Coast area are suited to this type of injection because receiving strata are porous, isolated from sources of potable water and their water is compatible with the liquid wastes to be injected. This method of disposal is a simple, complete and economical solution to the problems presented by certain hard to treat wastes.

Jan 1, 1964

By Agus Sasmito, SRIVATSAN JAYARAMAN SRIDHARAN, Akash Adhikari, Purushotham Tukkaraja

The amount of toxic fumes produced during blasting operation depends on the types of explosives used, product formulation, degree of confinement, conditions of use, and reactivity of the explosives with the host rock. Ammonium nitrate and fuel oil (ANFO) is still the explosive of choice due to its lower price and ease of use/loading. If not properly monitored and controlled, toxic fumes produced from blasting operations can have serious health hazards [1]. This paper presents a novel technique developed to track trapped fumes during a development blasting.

Aug 1, 2022

By E. J. Hammer

In the crushing and grinding of metallics for beneficiation, the sizing is normally done to liberate the metals or sulphides for further processing to improve recoveries of the basic metals or minerals. The objective is to reduce the ore in size through various closely controlled stages to that degree of fineness which gives an economic liberation of valuable mineral, but which avoids as much as possible the production of sliming fractions. A different philosophy applies to the crushing and grinding of Gypsum. Our requirements normally demand controlled grinding and/or crushing of the material not only to a fineness suitable for further processing of the mineral into end products, but to produce various sizes of material which are them- selves saleable products. The majority of our tonnage ultimately ends up in stucco for Wallboard. Therefore, our mineral reduction is normally designed toward this end, but it is done in a manner that permits drawing off inter- mediate products to meet various Customer requirements. This forces us into compromises at times in our equipment installations, and our equipment must sometimes be more versatile and complex than we would like it to be. We try to process our basic rock, Gypsum, for the most efficient size reduction. We market 5 to 6 different sizes intermediate to the end product, which generally is the fineness of material to be used for stucco for Wallboard, and we do this with controlled crushing, grinding and sizing cycles of the material. To summarize, we use a different philosophy of crushing and grinding than the metallic field which uses comminution or crushing and grinding to improve recovery, whereas we choose our equipment to crush and grind primarily for product performance.

Jan 1, 1969

By C. Geier

Previous mine incidents show weaknesses in mine rescue preparedness from poor training in decision making, leadership and incident command center (ICC) protocols. Computer simulations offer a larger range of training opportunities for mine rescue teams focusing on exploration and communications. The mine rescue simulator developed by the Colorado School of Mines and Rite Solutions Inc. utilizes four computers for the instructor and team, with the instructor monitoring the team?s progress. As the team explores, it relays information back to the Fresh Air Base, which then reports to the ICC. This forces a three-step communication procedure, enhancing the team?s overall communication skills and developing ICC protocols. The simulator is decision-based, demanding team decisions be made quickly. Upon completion, teams commented positively. Generally, participants said that the simulator is useful for learning how to communicate and make decisions during mine rescue emergencies. This mine rescue simulator improves team training, providing effective communications practice with an easy setup and no production interruption.

Feb 1, 2014

By M. Duane Lackey

Electric drives hire done outstanding job in many-fields that are related to the mining industry. The equipment that is offered for electric-trucks was developed from the traction equipment which is used on the diesel electric locomotive. Rotating equipment available for use on electric trucks is identical in principle to that which is used on these locomotives. In as far as it is practical, similar controls are used. Another descendent of the diesel electric locomotive can be found in the oil well drilling industry, Here, locomotive traction motors and. electric controls have been modified to fit the particular requirements of the drilling industry, One 2400 H.P. diesel electric drilling rig drilled a 24,000 Ft. well in West Texas with an electrical maintenance cost in the order of 7¢ per hour This was a new rig and the costs are less than the average maintenance costs will be for the life of the equipment, Even soy since it took one (1) year to drill this well, this 7¢ per hour has real significance. Electric shovels use a similar type of electrical equipment; they too have shown real savings over the equipment they replaced. Since electric drives have done so well, in other fields, they warrant consideration for use in high horsepower, large capacity trucks.

Jan 1, 1961

By Shiro Ishii

When construction sites are in a densely- populated area or near roads, railroad or river, restrictions upon the ways of handling and using explosives such as dynamite and large demolition equipment are being increasingly stringent, in consideration of environmental pollution such as noise, vibration, dust, flyrocks etc., and safety precaution. In view of this, the development of safe and pollution-free technology for demolishing rocks at mines and reinforced concrete structure at building sites is strongly required. To meet such requirements, the demolition by means of expantion of mineral substances has been considered long before. Recently with the demolition technique using non-explosive demolition agent developed by ONODA CEMENT CO., LTD., holes are drilled into substances to be demolished, such as rocks and concrete before-hand. Then, slurry of such agent mixed with an appropriate quantity of water is poured into the holes. It hardens and expands with the passage of time, and the expansive stress reaches more than 3m/m2 in 10 to 24 hours. This expansive stress causes the material to crack. In this article, descriptions of the non- explosive demolition agent, BRISTAR manufactured by ONODA CEMENT CO., LTD., TOKYO, JAPAN, are given briefly with regard to its physical and chemical properties and its method of use; and the way it is used at an actual construction site is reported.

Jan 1, 1982

By A. T. Yu

There are compelling reasons for us to look to our Country's Western coal. Despite its inherent low BTU content, Western coal's low sulphur content provides a near-ideal answer to satisfy our in- dependent goals of clean air and self-sufficiency in energy. Vast reserves, thick seams and amenability to low-cost strip mining serve as a powerful economic basis for its viability as a primary and dependable source of energy for the coming decades. A major consideration, the solution of which may not be quite obvious, is transportation cost. These abundant deposits are remote from the utilities of the heavily populated eastern regions of the United States (Figure 1). A Western coal mine in Montana is likely 1500 miles or more from an eastern power plant. The comparable distance to an eastern coal mine may be only 200 miles. Thus, the question is: How can the haulage cost of our Western coal be substantially reduced to an acceptable level? If resolved, western reserves of coal will be one of the key solutions to satisfying our Nation's energy needs.

Jan 1, 1975

By M. Akram

Stability assessment of entry roofs is an essential precursor to all underground design. Both multi-seam interaction and longwall mining can subject entries to radical changes in the surrounding stress field. Such loading changes frequently produce instability and failure in the roof, floor and pillars. Roofs are shown to be vulnerable to stress-induced failures, particularly when the load is unsymmetrical. To predict the effects of changes in stress field, roof failure conditions under increasing loads were studied using finite element analysis and body loaded photoelastic models. A large range of geologic conditions were evaluated and incorporated into the model using Monte Carlo methods. Entry analysis using the model showed the roof to be particularly vulnerable to shear with the location of the failure site changing to meet loading and geologic conditions. Results were correlated with field data to determine stress levels at which failure could be expected to occur. Based on this research a roof stability model SESAME was constructed for roof stability evaluation under specified loading conditions.

Jan 1, 1993

By R. Zins

During the past few years, a completely new concept has been applied to the design of drives for operating at very low speeds. In this, the motor is supplied by a variable-frequency thyristor cyclo-converter. Today, frequency converters with practically unlimited power ratings can be constructed. The system frequency of 50 or 60 Hz is reduced to about 10 % of these values. This makes it possible to operate the synchronous motor, which has a correspondingly high number of poles, at the extremely low speed of the driven mill, i.e, without interposed gearing. The first motors of this type were built to drive ball mills in the cement industry, which are very similar to those employed for ore processing. Here, too, the tendency is to build units of ever increasing capacity. In the case of conventional drives with mechanical gearing, this involves correspondingly increasing difficulties. These difficulties have prompted various studies of the possibility of applying the new type of drive to ore mills as well, but a gearless drive has not yet been built for this application. However, gearless drives for ore mills will certainly materialize soon and it was therefore considered a logical step to report at the A.I.M.E. Conference on the experience gained with these drives in the cement industry, and on the present state of development.

Jan 1, 1973

By D. R. Rice

Separation of valuable constituents from a complex mineral mixture was examined. Nitric acid leaching produced a solution containing copper, zinc, iron and a large proportion of silver. The residue contained antimony, lead, the remaining silver and elemental sulfur. A caustic sodium sulfide leach dissolved the antimony from the residue, producing an insoluble, high-grade silver-lead product and a filtrate for electrolytic recovery of antimony. The pH of the primary filtrate was raised, precipitating the iron and leaving a solution containing the copper, zinc and the soluble portion of the silver, which would be recovered by conventional means.

Jan 1, 1969

By Robert E. Frey

Regardless of the mechanical design features of a particular air classifier certain basic principles apply. Specifically , there are two forces at work: 1. An air drag force 2. An inertial or centrifugal force. The air drag force has an increasing influence as particles become smaller. A very small low mass particle is easily carried along with an air stream even when turning a corner. Thus, fine particles follow the air away from the classifying zone. Inertial forces increase as the mass of a particle gets larger. Thus oversize particles tend to obey Newton's laws and respond to centrifugal forces or simply continue in a straight path when the airflow changes direction.

Jan 1, 1985

By C. R. Tinsley

Valuations can be molded, twisted and misinterpreted. Cases of spurious scope setting; limits to the information or access by the valuer; difficulties with the lack of comparative valuations; inappropriate valuation methods and outright speculations are described. None should be accepted by an experienced, independent minerals valuer. The Australasian Institute of Mining and Metallurgy (TheAusIMM) is working on a Valmin Code for which a Manual of Best Practice and Valuation Guidelines may be developed.

Jan 1, 1995

By D. C. McLean

One of the few innovations in hydrometallurgy in recent years has been the utilization of the chemistry of basic iron sulfates called jarosites. These have been used to make iron-zinc separations in the processing of zinc concentrates and are a very important factor in both the Duval and Cymet copper chloride processes as a means of preventing iron build-up in the closed leaching circuits. Copper oxychlorides are kindred compounds in that they are insoluble basic salts that form at low pH (1.5 to 3) and precipitate selectively from many base metal solutions. They have been reported in the chemical literature as far back as 1860, and a few of them are known in their mineralogical forms (particularly atacamite) usually as nuisance minerals because of their chloride content. Several patents describe their synthesis and use as fungicides and insecticides, and papers have discussed their formation as corrosion pro¬ducts on copper and brass piping (14).

Jan 1, 1979

By L. Yuan, J. H. Rowland, R. A. Thomas

Hydrogen (H2 ) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system. In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, H2 concentrations in the airflow are constant, while in the full-scale experiments, increasing H2 concentrations generated as a byproduct of charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to safeguard underground miners.

By Kathleen Lagnese, Srikanth Muddasani, Kashi Banerjee, Carla Robinson

"Mine water generated from underground coal mining operations contains both dissolved and particulate solids. Dissolved solids primarily consist of sodium, calcium, magnesium, potassium, chlorides and sulfates. When discharged to a receiving stream without treatment, these constituents create a potentially toxic environment for aquatic life.A case study is presented to discuss how a centralized treatment plant treats mine water from six locations to meet discharge limitations for chlorides. Located in West Virginia, this facility consistently achieves less than the National Pollutant Discharge Elemenation System (NPDES) permit limitation of 218 mg/L chlorides in the discharge while generating almost zero liquid waste. The dissolved solids concentration in the influent ranges between 5,000 and 10,000 mg/L, with chloride concentrations of 1,000 to 2,000 mg/L and sulfate concentrations of 2,000 to 6,000 mg/L.The mine water is treated using advanced treatment technology to produce clean water for discharge or reuse. The treatment process comprises aeration, softening, filtration, reverse osmosis (RO) reject softening, evaporation, crystallization, final effluent remineralization and sludge dewatering. The solid waste generated in the treatment process is landfilled on site. The leachate is sent back to the facility’s thermal treatment process. Because no liquid waste leaves the property, this plant is termed a zero liquid waste (ZLW) facility.The advanced water treatment system was built to meet a new 218 mg/L regulatory limitation imposed by the West Virginia Department of Environmental Protection for chlorides discharged to surface waters. The system is designed to treat a maximum flow of approximately 795 m3/h (5 million gpd) of mine water. The treatment process utilizes RO membrane treatment to achieve the effluent criteria, and evaporation and crystallization technology to manage the RO concentrate from the water treatment process. As a result, the system produces clean water for discharge while generating zero liquid waste. The effluent water can be used for industrial purposes or discharged to a receiving stream. A water impact index (WIIx) study indicated that discharge of this high-quality water into the Monongahela River watershed may improve the water quality for downstream water users. The waste produced in the treatment process, including softening sludge and salt, is disposed of in an onsite landfill. Currently, the plant is treating at an average flow of 490 m3/h (3.1 million gpd) of mine water with an average influent chloride concentration of 1,530 mg/L and an average effluent chloride concentration of 11 mg/L."

Jan 1, 2014

By Eugene W. Price

One of the most important fundamental characteristics of iron ore pellets is their porosity. This importance arises from the fact that the pores are the busy avenues whereby many changes are brought about in the life and form of the pellet from the time it is made until the iron it contains emerges as a molten stream from the blast furnace. As a green iron ore pellet is first heated in the drying cycle of a typical heat-hardening process, the pores act as conduits to allow the escape of steam from the water or vapor from the oil which served as binders to hold the green pellet together. After the release of the steam (or oil vapor) the pores then act as conduits whereby oxygen can enter the pellets to 1) convert magnetite (Fe304) to hematite (Fe203), if appropriate, and 2) promote solid state grain growth between adjacent particles of iron ore. The rate of oxidation and the rate of grain growth are directly related to pore size' and pore size distribution. Rate of oxidation is also directly influenced by length of pore and length of pore is obviously related to pellet diameter. It is well to keep in mind that the heat-hardening process does not harden the mineral grains themselves. What it does is weld them together to change the green pellet from a doughy mass, composed of thousands of tiny individual particles, into a strong, intergrown monolithic structure. In the blast furnace the pores again act as conduits for gases, but in this case they trans¬port reductants such as hydrogen (H2) and carbon monoxide (C0) which remove most of the oxygen from the ore. Rate of reduction is also directly related to pore size and pore size distribution.

Jan 1, 1967

By J. B. Knaebel

I have been asked to discuss the "Development of the Twin Buttes Mine for Production." This property, which is a large low-grade open pit copper mine about 25 miles south of Tucson, Arizona, was recently brought into production by The Anaconda Company under a long-term lease agreement with the Banner Mining Company. Since the scope of this paper is limited to the subject broadly indicated by its title I will confine discussion of historical, environmental and other general matters to a brief summary sufficient, I hope, to establish a background of those conditions which influenced our approach to the technical and economic problems that faced us at Twin Buttes. The paper deals primarily with our studies and activities related to the solution of these problems and with the resulting engineering and business decisions that were taken - decisions which culminated last September in the initial commercial operation of another major open pit copper producer unique and interesting in several respects.

Jan 1, 1970

By J. L. Uhrie

A potentially cost effective technique for the reclamation of heavy metal contaminated soils and sediments involves the technique of froth flotation. Heavy metals sorbed to clays in the soil may be sulfidized by the introduction of sodium sulfide and floated using a dithiophosphate collector. Separations were obtained where up to 78% of all copper ion was removed from the system. Selected samples were floated in a column cell but little advantage was seen.

Jan 1, 1996

By John L. Shafer

A process for the conversion of stibnite (Sb2Sj) concentrates, crude antimony oxide, or metal to a pure cubic antimonous oxide (senarmontite) has been developed on a laboratory scale. The conversion of stibnite to senarmontite has been piloted. The high purity of the final product is the result of forming antimony trichloride as a low temperature distillable intermediate. To obtain the antimony trichloride the stibnite, or crude oxide is slurried in molten antimony trichloride and reacted with gaseous hydrogen chloride. Antimony metal is oxidized to the trichloride with chlorine. The hydrogen sulfide produced from the hydro- chlorination of stibnite can be upgraded to a strength of 95% or greater for further treatment. The crude antimony trichloride is separated from the gangue by a preliminary evaporation and then is fractionally distilled and the trichloride distillate has less than 50ppm of arsenic and lead combined (the most troublesome impurities in antimony processing). The purified antimony trichloride is then hydrolyzed with sodium or ammonium hydroxide to produce the cubic form of antimonous oxide (senarmontite) to the exclusion of the rhombic form (valentinite) which is photosensitive. The advantage of this process is the ability to treat a wide range of antimony ores, concentrates, and metal to yield a high purity oxide in a controllable range of particle sizes.

Jan 1, 1975