Search Documents

By K. T. Valsaraj, L. J. Thibodeaux

Solvent sublation, the separation process for the removal of two hydrophobic compounds (penta- and trichlorophenols) from the aqueous phase, is discussed, as is a steady-state mathematical model for fire process. Solvent Sublation "'as conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1994

By J. R. Pennington

The town of Green River, Wyoming, is located along the Green River on an arid plateau at a elevation of 6,300 feet. Green River has become the center of a booming soda ash industry. The rapid development of coal, oil, and gas resources, coupled with the soda ash boom, have created growth pains for the area. Green River and Rock Springs have experienced a 20-25% population increase in 1973 alone. However, public officials, business leaders, and local citizens are taking positive steps to ease the problems relating to housing, schools, medical services, and recreational facilities. What Is Soda Ash? Soda ash is one of the most widely used chemicals in the world. It is an important raw material in the manufacture of glass, paper, soap, petroleum products, metals, chemicals, pharmaceuticals, plastics, and a host of other items essential to every day living. In ancient times, soda ash was obtained from water solutions of various desert earths. Later, it was produced by leaching the ashes of wood and seaweed. For the past 100 years, it has been manufactured by the ammonia-soda process, which employs large quantities of salt, limestone, and coal as raw materials.

Jan 1, 1974

By R. W. Utley

The purpose of this study was to seek and evaluate possible relationships between the composition of coal refuse, as expressed by washability data, and factors affecting the product ion of a lightweight aggregate from refuse by bloating. The study was related to an intense program in the Department of Mineral Preparation at the Pennsylvania State University to study the possible elimination of air pollution from coal refuse fires by producing a low- carbon secondary refuse. Another phase of this program is considering possible uses of such a secondary refuse. Thus one study was to determine if a lightweight aggregate could be produced from this new refuse material and what effect the nature of refuse beneficiation would have upon the characteristics of a commercial aggregate product.

Jan 1, 1965

By M. K. Buder

Over the years, electric utilities have been faced with declining steam-coal quality, rising coal prices, and increasingly rigid and costly environmental standards. As a result, many utilities are beginning to show an interest in coal cleaning to upgrade coal by improving its heating value and reducing its sulfur content. Among the primary questions that must be answered for these electric utilities is whether the cost of coal cleaning can be offset by the potential cost savings in coal transportation and utilization in power generation. In search of at least a preliminary answer to this question, the Electric Power Research Institute (EPRI) engaged Bechtel to perform a case-by-case economic study to examine the cost effects of using cleaned versus raw coal to fuel new electric power plants. The results of two of the seven cases studied which involved western coals - one from Montana and another from Utah - are reported in this paper. Coal cleaning appeared to be a cost effective option for the Utah coal, but only marginally economical for the Montana coal. These cost results are expected to change to favor coal cleaning to a greater extent with the application of the final revised New Source Performance Standards regulating SO2 emissions just issued by the EPA. The study was based on the regulation originally proposed by the EPA under the 1977 Clean Air Act Amendments.

Jan 1, 1979

By Evan Dressel, Mark S. Diederichs, Kathy Kalenchuk

As hard rock mining develops deeper over time, there is an increasing need to predict the spatial and temporal distribution of adverse seismogenic rockmass reaction to mining. Real-time monitoring and feedback of mine data are used to tactically manage risk associated with induced-seismicity; however, strategic risk management requires reliable tools for forward predictions of seismic hazard. The forward prediction of seismic hazard is strengthened by understanding of potential seismic intensity, which often relies on well calibrated mine-wide numerical models. This paper uses a case study to explore how future seismogenic potential and the nature of future seismicity can be domained according to numerically predicted stress-strain paths at past seismic event locations. Delineation of high confinement seismogenic volumes vs. lower-confinement, high-strain seismogenic volumes at the mine-scale can be achieved, based on a loading and unloading stress path analogue, to refine understanding of seismic intensity. Practical qualitative and quantitative methods to achieve this delineation will be demonstrated. Once seismogenic mode (high-stress vs. high-strain) is identified, detailed analyses of seismic source parameters demonstrates change in seismic hazard between the domained volumes.

Apr 26, 2022

By C. C. Harvey

Asia is experiencing a growth market for industrial kaolins for use in ceramics, paper, plastics and other market sectors. Export and import data for the Asian countries reflects this growth with the Peoples Republic of China as the major exporter of clays and Japan the major importer. The growth in tonnage and product sophistication of kaolins produced on Belitung in Indonesia is typical of developments that are taking place in many locations in Asia. This region therefore presents opportunities for mineral processors and a challenge for the exploration geologist, the mineral processing engineer, the mineral economist and the marketing specialist.

Jan 1, 1996

By E. L. Montgomery

Salar basins in the Andean Highlands of Northern Chile contain ground-water resources which could be used to satisfy requirements for the mineral industry in the region. Salars occur in arid zones; average precipitation is about 200 millimeters per year at altitudes of about 4,000 meters, and average annual evaporation is two meters or more. The salar basins are hydrogeologic sinks where water flows from recharge areas at the margins of the basins to discharge areas at the salt encrusted salar at the lowest point of the basin floor. Groundwater circulation occurs principally in the alluvial and fractured bedrock aquifers. Results of pumping tests for exploration and production water wells indicate a range in maximum sustained pumping yield of 62 to 126 liters per second, and where abundantly fractured, ignimbrite comprises the most prolific aquifer. Chemical quality of groundwater is good. Long-term pumping from properly located production wells in the salar basins would result in lowering of groundwater levels and salvage of water in areas where groundwater is lost via evaporation.

Jan 1, 1986

By J-P Franzidis, M. C. Harris

Increasing costs, falling grades and a low gold price have caused severe problems for many of South Africa's gold mines. The need to maximise efficiency is extremely urgent. This paper describes the use of column flotation cell s to scavenge significant quantities of additional gold from flotation plant residues; in particular, very fine particles of free gold not recovered by conventional flotation. Experimental gold- specific collectors enhanced gold recovery significantly. The paper also reports the results of other plant trials, carried out on a variety of ores.

Jan 1, 1991

By Edward J. Budill

One of the most dramatic innovations in the materials handling industry has been the development of stacker cranes and automated material handling systems. The stacker crane with its many capabilities and the development of reliable industrial automation controls have combined to produce dramatic achievements in an area once characterized by inefficiency lack of management attention, and capital investment. In many areas of application however, stacker cranes and high rise storage systems have been designed and installed with insufficient thought given to their integration into the overall operations of the plant or distribution facility. This paper will look at some new and interesting breakthroughs in the integration of stacker cranes and high rise storage systems into the total manufacturing plant system. In this paper we will refer to both bridge type stacker cranes and aisle stackers. The bridge type stacker crane was developed first and was initially developed with forks or other handling devices hoisted up and down a rigid or telescopic mast. This mast system was suspended from a trolley mounted on an overhead crane bridge. Today, the primary application of the bridge type stacker is in warehousing systems for handling basic metal products such as coils, bars, sheets and plates. There is no question that the bridge type stacker has achieved notable results in storage and handling of these commodities. However, a new area for stacker crane application has been developing which in many cases over-shadows the accomplishments in the storage area. This is the application of the bridge stacker as an integral part of the manufacturing processes, or in other terms the production applications of stacker cranes. The stacker crane has a number of attributes which makes these applications very important. First, the crane bridge provides the stable platform for the mounting of machinery which can accommodate the hoisting and lateral movement of large capacity loads. Today stacker cranes are being built with capacities of up to 30 - 40 tons. The bridge cranes can easily accomplish accommodation Of these large tonnages. Secondly, the mast system provides a stable platform for the mounting of a wide variety of manipulating devices which can be used for the placement of material into manufacturing processes, the extraction of this material from these processes, and movement to other points in the process area. These attributes combined with excellent operator control and safety have led to development of the stacker crane as a production tool.

Jan 1, 1973

By Phillip O. Tyree, R. A. Metz, Joseph W. Mussey

Bio-epigenetic sulphur deposits occur in Pecos, Reeves and Culberson counties of far West Texas. Sulfate reducing bacteria, utilizing hydrocarbons as energy, transformed gypsum into replacement limestone and hydrogen sulfide. Hydrogen sulfide, retained in the pores of the replacement limestone, was subsequently oxidized by highly oxygenated groundwaters, and native sulphur precipitated. West Texas sulphur was first recognized at surface exposures by William P. Blake, a geologist attached to the Captain Pope Military/ Scientific Expedition of 1854. Attempts were made in the early 1900's to mine these sulphur vent exposures by a retort method, but the ventures met with little success. In 1967, Duval discovered a large sulphur deposit near some of the old sulphur works in Culberson County. Duval also expanded reserves in a small sulphur deposit in Pecos County. The Frasch process, developed for producing sulphur from Gulf Coast salt domes, proved successful in West Texas type sulphur deposits also. However, modifications of the process were necessary to provide economical and efficient sulphur recovery from the varied ore occurrences. West Texas conditions and logistics require the ultimate in productivity to be competitive in the domestic and foreign sulphur markets. Several companies, in addition to Duval, are producing or have produced sulphur in West Texas. As of June 1, 1984, a total of 29.87 million mt (29.4 million long tons) of sulphur had been produced west of the Pecos River. Duval corporation has produced more than 88 percent of that total.

Jan 1, 1992

By E. Fregeau-Wu

To recycle steelmaking slags for their iron, manganese, and lime contents, removal of the phosphorus-bearing dicalcium silicate and calcium phosphate is essential. Slow-cooling of slags was necessary to promote the sufficient grain growth to achieve liberation. In-situ grain size distribution determination showed that a high soaking temperature, a long soaking time, a very slow cooling rate, and the addition of fluorspar were shown to promote grain growth. High gradient magnetic separation on slow-cooled slags removed much of the dicalcium silicate. Liberation modelling was used to discuss the breakage and beneficiation characteristics of the slow-cooled slags.

Jan 1, 1992

By Robert C. Cifelli

INTRODUCTION Background and Objectives Underground coal mining is a vital component of West Virginia's economy. However adverse environmental effects including ground subsidence and aquifer dewatering are often associated with such mining activities. Many families in northern West Virginia still rely on private water wells and springs for domestic water needs. In such areas where underground coal extraction and land subsidence have occurred, a disruption of the ground water flow system commonly exists with subsequent drainage of water to lower levels that may extent as deep as the mine workings; this causes loss of water supplies to landowners and represents a nuisance to mining companies 2 This report represents a summary of an M. S. thesis project in geology at West Virginia University by the senior author (3). The intent for this study was to document the effects of underground coal removal on ground water levels at selected mine sites in northern West Virginia, as observed from water wells, springs, and streams. This research should be useful to coal companies and regulatory agencies and aid in recommendations of future water well locations and specifications in areas of existing or proposed underground coal mines.

Jan 1, 1986

By E. E. Caba

Copper smelter flue dusts containing arsenic are hazardous materials requiring environmentally accept-able disposal, preferably with re-source recovery under the RCRA and CRCLA regulations. However, the known resource recovery processes entail capital and operating costs greater than can be justified by the revenue of the recovered metal. Consequently, the smelting industry is tending to forego resource recovery in favor of encapsulation and storage in a certified class I hazardous waste site, or in a dedicated facility located at the source Superfund site. Order of magnitude costs for this option with portland cement encapsulation are estimated at $100 per ton, not including transportation. Industrial adoption of a new resource recovery process re-quires that its cost, including capital amortization, exceed the cost of encapsulation and storage only by the amount of the offsetting revenue from sale of metal. The lime-roast/ammoniacal leaching process is expected to meet this goal.

Jan 1, 1992

The Global Mining Standards and Guidelines Group (GMSG) is building an international, multi-stakeholder community to advance the availability and use of standards and industry guidelines for the global mining community. Standards and guidelines are key strategic tools for operational excellence, enabling companies to move forward with efficient, innovative operations with reduced risk. Launched in May 2012, the GMSG is the first international center to bring together information, resources and collaborative projects for mining standards and guidelines, in an open, knowledge-sharing forum. The GMSG is supported by five partner organizations providing outreach and helping to guide GMSG activities: the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy and Exploration (SME), the Australasian Institute of Mining and Metallurgy (AusIMM), the Southern African Institute of Mining and Metallurgy (SAIMM) and the Surface Mining Association for Research and Technology (SMART). GMSG was formed under the CIM Surface Mining Society, though its mandate extends to include underground mining as well. ?SME is supporting the GMSG as a key international activity to advance the implementation of standards and guidelines in our industry, and to provide a forum for our members to access, and contribute to, projects and information to assist their operations,? said SME Executive Director David Kanagy. ?We see the GMSG as a good example of ways the major mining associations can work together for the benefit of all our members.? The GMSG charter encompasses all standards and guidelines that apply to mining; however, a number of subject areas are now being spearheaded by six working groups, namely: ? Access and usage of data from mobile mining equipment onboard systems. ? Operational safety. ? Situational awareness (namely, a unified equipment operator interface). ? Underground operations. ? Asset management and operations data definitions and KPIs. ? Energy in communition.

Oct 1, 2013

By Yoginder P. Chugh

The control of soils has been found to be one of the highest priority factors influencing the return of reclaimed prime farmland to production. The compaction of soil is primarily a result of the movement of high ground pressure wheel scrapers and dozers over soils during the soils replacement and regarding process and occurs to a maximum depth of about 1.2 m (4 ft) The deleterious effects of soil compaction can be controlled by deep soil loosening to a depth of 1.2 m (4 ft). Most farm tillage equipment can only loosen soils to a maximum depth of 0.33 m (1.0 ft). Deeper soil loosening equipment, in the 0.33-1.2 m (1.0-4.0 ft) range is currently avail- able in the U.S. and abroad which may have potential for application on reclaimed prime farmland. This study has appraised such available equipment and the results indicate that a few manufacturers in the U.S., West Germany, and England market static and vibratory soil loosening equipment which have potential for deeper soil loosening of reclaimed prime farmland.

Jan 1, 1985

By Richard J. Goff

Technical Support, one of several major organizational units in the Mine Safety and Health Administration, provides technical assistance to the mining community in all areas of health and safety. One of its many areas of expertise is noise control. Depending upon the needs of the operator or inspector, the services provided can range from locating major noise sources to actually building noise controls. Over the years a vast amount of knowledge has been obtained as to what will work and what will not. DESIGN GOALS While many noise controls have been developed for mining equipment and operations, the most acceptable (ergo successful) have achieved the following design goals: - a noise level reduction of at least 5 decibels; - minimum interference with production; - inexpensive to install; and - effective in reducing low frequency noise.

Jan 1, 1984

By Francesco Chiappalone, Franco Gasperin, Fabrizio Fara

This document describes the challenging task of mining through tiebacks using a 21'-8" diameter Tunnel Boring Machine (TBM) as part of the Ship Canal Water Quality Project. The mining operation involves navigating through 17 tie-backs that are evenly spaced at 8-foot intervals, with many intersecting the full face of the cutterhead. Detailed analysis and review of TBM parameters specific to this area have been conducted to ensure operational efficiency and safety. Hyperbaric interventions have been planned and coordinated, encompassing pre-mining preparations, continuous monitoring and adjustments during the mining process, as well as post-mining measures. The document highlights the complexity and importance of strategic planning and execution to successfully overcome the tie-back intersections during the mining operation.

Jun 23, 2024

By Evangelos Spyridonos, Thomas Frommer, Wolfdietrich Skala, René Prissang

Operational grade modelling is a technique that uses production data to run daily updates of property models. It will enable mining engineers to use property predictions based on the most recently acquired data as support for quality control and decision making. The approach necessitates that the properties of the run- of-mine material can always be attributed to individual mining blocks or charges. The software employed must be highly reliable, because a system failure or the loss of data could seriously affect the mine's quality management. An operational grade modelling system has been developed for the Breitenau magnesite mine. It makes use of the Linear Octree Based Property Modelling system which was conceived and realised at the Free University of Berlin. This paper describes the system design and gives an account of the experiences during the first six months since system start-up.

Jan 1, 1996

By A. E. Isaacson

Researchers at the Bureau of Mines, U.S. Department of the Interior, developed and tested equipment to measure corrosion rates on a commercial-scale mill. Bench-scale experiments were also designed for duplicating ore grinding conditions closely enough that realistic rate determinations can be made in laboratory tests. Rates measured in a laboratory system compared favorably with those measured in the field. Cast steel was found to have corrosion rates in a copper mill and laboratory test cell of 22 and 21 mpy, respectively. Corrosion was found to account for less than 5 pct of the total grinding media wear in the operations studied.

Jan 1, 1989

By R. Mensah-Biney

The loading characteristics of gold-tetrabromide species onto activated carbon have been evaluated using a completely mixed batch reactor system. The overall loading of gold onto carbon was rapid for the first hour but continued slowly without cessation as a result of reduction of gold. Conventional equilibrium considerations were therefore not applicable. Although loading continued slowly after several days, abnormally high loading capacity values of 10-12 meq/g carbon (650-800 kgAu/tonne) could be attained within 72 hours. The loading of gold-bromo species by activated carbon was by the mass transfer of [AuBr4l-onto the carbon surface where reduction to metallic gold took place. Elution of gold from the loaded carbon was feasible provided the carbon had not been loaded to too high capacity values. If loading is carried to high levels, complete elution becomes impractical and the gold may be recovered by ashing the carbon. For the high loading capacities observed, this option would appear to be cost effective. The effect of several variables on the loading capacity of the activated carbon is discussed.

Jan 1, 1992