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By Sureshan K. Moothedath

This paper provides a mechanistic representation for floc formation, growth and degradation and presents results from an experimental study of batch flocculation in which step changes were made in the impeller speed, flocculant addition, and slurry concentration. A discussion of the experimental results is included in terms of the mechanisms of floc formation and size-change.

Jan 1, 1993

By M. Rodgers

Dow Water & Process Solutions (DW&PS) was approached by ASARCO Inc. to attempt to recover cobalt and copper from their copper solvent extraction (SX) raffinate. Cobalt is added to many copper electrowinning tankhouses to help to prevent lead electrode corrosion. With cobalt?s high price this can be a large expense. ASARCO has ore that contains a small amount of naturally occurring cobalt. Currently they have no way of capturing this high value metal from their leach or raffinate streams. DW&PS has some chelating resin technologies that should be able to help solve this problem.

Jan 1, 2010

By Ronald M. Hays

During the twentieth century the Mesabi Range in northeastern Minnesota has been the major source of iron ore for American steel mills. The Mesabi Range extends along an iron bearing outcrop known as the Biwabik formation. This outcrop is some 120 miles long and up to three miles wide. The formation is from 200 to 650 feet thick and dips 5 to 10 degrees to the southeast. The iron content of the original Biwabik formation was quite uniform, but much of this formation has been subjected to alteration. Thus major variations in iron content and mineral composition exist both laterally and vertically in the present Biwabik formation. The remaining unaltered iron formation includes the magnetic taconites which are commercially processed by Reserve Mining, Erie Mining, Eveleth Taconite, National Steel, Butler Taconite, and U.S. Steel. These six operations have a capacity of 32 million tons. per year of iron pellets and have produced approximately 170 million tons of pellets since 1956. Capacity for another 30 million tons per year of pellets is being considered by the industry for the next ten years. This increase will be obtained by construction of new plants and expansion of present operations. Thus by 1977, it is estimated that approximately 60 million tons per year of iron pellets will be produced from magnetic taconite on the Mesabi Range. The portions of the Biwabik formation subjected to intense alteration resulted in the direct shipping, wash and heavy media ores. Since 1892, 1.8 billion tons of direct shipping ore have been shipped from the Mesabi Range. This ore has been the major source of iron for American steel mills. In 1966, 12 million tons of direct shipping ore and 18 million tons of wash, jig, heavy media and other gravity concentrates were shipped from the Mesabi Range. These products generally have poorer physical and chemical properties than the iron pellets produced from magnetic taconite. It is predicted that the shipment of these materials will decrease from about 30 million tons in 1966 to 6 to 8 million tons in 1975. This decrease will be due to depletion of reserves and poor quality product.

Jan 1, 1968

By Ehsan Moosavi, Kamyar Tolouei, Mehran Gholinejad

The literature defines rockbursts in slightly different ways based on their generation mechanisms, field phenomena, and degree of damage, but in a way that is almost consistent. Generally, a rockburst refers to seismic events that mainly happen in underground excavations, for purposes such as underground mining, road and railway tunnels, nuclear power, etc., and that are followed by the collapse and outburst of rocks. Long-term rockburst prediction can be abstracted as a classification problem mathematically, in which we can introduce deep learning to solve it. Further, using deep learning in rockburst prediction can overcome drawbacks such as subjectivity and inconsistency brought from previous traditional approaches. A rockburst data-set, was employed to evaluate the current method for predicting rockburst grade, and the good results of overall success rate were obtained. The results indicated that the proposed algorithms can speed up parameter optimization search, the proposed method is robust model and might hold a high potential to become a useful tool in rockburst prediction research.

Apr 26, 2022

By Ben H. Daud

A computer model has been developed at Consolidation Coal Co.'s Central Engineering Dept. for preliminary economic evaluation of deep coal mine reserves. Since it was first formulated more than two years ago, the model has been used for the following purposes: (1) ranking studies of coal exploration projects, (2) marketing surveys, (3) preliminary sale and acquisition analysis of coal reserves, and (4) parametric analysis in conjunction with detailed feasibility studies.

Jan 1, 1979

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 M. R. Paterson

Operational and economic factors tend to favor the application of continuous processes in preference to batch processes in the majority of mineral processing applications. In this paper, the requirement for a Continuous Elution Process is established and the development of a large-scale pilot plant is described. It is based on a Continuous Elution apparatus which has a number of special features. These are the subject of various patent applications. The apparatus is suitable for adaptation to the AARL, Zadra and other methods of elution. The performance of the Atmospheric Continuous Elution System (ACE) is concluded to have significant advantages over the batch process.

Jan 1, 1986

By R. D. Bartlett

Large open pit mines in desert climates, such as the Phelps Dodge Morenci copper mine in Arizona, can create groundwater cones-of-depression of considerable size and :ability. The hydraulic containment provided by the groundwater depression prevents migration of process solutions into the surrounding regional aquifer. Copper leach operations that fall within the groundwater depression may not require costly lining if passive containment can be demonstrated. An approach is presented in this paper that was successfully used to demonstrate passive containment. The approach includes a combination of groundwater modeling and a water balance analysis of leaching operations failing within or immediately near the open pit.

Jan 1, 1999

By A. A. Schweizer

Buckhorn ore is hydrous, argillized basaltic andesite, and is at least 60% clay composed of kaolinite and subordinate montmorillonite. Moisture content runs from 10% to 25%. The original crushing plant was a typical compression type, employing a jaw crusher, and two cone crushers. The system was plagued with constant plugging and unable to meet production plans. The three compression crushers were replaced with a Stamler Feeder Breaker followed by a Hazemag Impactor. Production plans are now exceeded. Agglomeration has progressed from an agglomeration drum to cascading conveyors, to introduction of the lime and cement into the primary crusher.

Jan 1, 1987

By James A. Decker

Hanna has developed three production planning systems to help the mine engineers determine the sequence of mining from available ore supples. The Production Scheduling System was developed to give the staff a tool for long range planning by sequencing the removal of blocks from an open pit property. It was needed to determine the year of removal for each block so that the optimum present-valued pit limits could be established by our pit design program. Since in this type of planning short term grade control is less of a factor than it is in daily or monthly planning, the system gives the program greater control and more latitude in block selection. It permits only full blocks to be taken.

Jan 1, 1984

By Nico Sutmoller, Rich Palladino

Underground voids present a unique geotechnical engineering challenge. This paper will address materials and transportation mediums that are typically used for backfilling underground voids with native material. After reviewing traditional backfill and transportation methods, this paper will explore the advancing technology of foam transportation and the advantages of using this technology for transporting fill materials into underground voids to backfill them with Liquid-Sand. The paper will also review the benefits that Liquid-Sand brings to these applications and highlight specific case studies in which foam transportation has proven effective and provided cost-effective, environmental benefits.

Feb 1, 2025

By Timothy Batchler, Khaled Mohamed, Morgan Sears

The National Institute for Occupational Safety and Health (NIOSH) initiated a testing program to assess the effects of lateral loading on various standing supports used in underground coal mines. This study is not intended to endorse a particular type of standing supports nor to provide a comparison between different types of standing supports. This paper aims to measure the lateral loading capacity of two types of standing supports and evaluate how it affects their vertical loading capacity and yielding mechanisms. The study utilizes the Mine Roof Simulator (MRS) at NIOSH Pittsburgh. Type-1 support is characterized by telescopic tubes made from ASTM A-513 steel with a specified locking mechanism, and Type-2 support comprises a single component constructed from ASTM A500 Welded Grade C pipe. Vertical load tests were carried out to assess the designed performance of Type-1 and Type-2 props. Type-1 props demonstrated a "constant yielding" behavior, achieving an ultimate capacity of up to 140 kips. Type-2 props showed a "load shedding" behavior, reaching peak verti- cal loads of up to 191 kips. Buckling analysis revealed that Type-1 props were not designed to buckle, and Type-2 props failed due to buck- ling rather than material yielding. Under vertical pre-loading, lateral loading tests showed that Type-1 props can withstand about 9 kips, and Type-2 props can withstand about 10.79 kips of lateral load. This represents roughly 6% of their vertical loading capacities. Testing props under lateral loads in addition to their intended vertical loads showed that the lateral loads could influence their loading mechanisms. Type-1 props did not exhibit the expected "constant yielding" behavior under lateral load but instead showed "load shedding" decreasing their rated vertical capacity by 70%. At high vertical pre-loading, Type-2 props demonstrated "constant yielding" behavior instead of the anticipated "load shedding," leading to a 60% reduction in their rated vertical capacity. These findings provide valuable insights into the behavior of these props under different loading conditions, aiding in their efficient use and design in underground mining operations.

Jun 25, 2024

By R. S. Shoemaker

Environmental and regulatory authorities are increasingly requiring that precious metals heap leach piles be contoured before they are abandoned so they may present a more "natural" look to the eye. Depending on the ore type, many of these contoured heaps will be subject to substantial erosion by precipitation events, native plants will have difficulty in establishing themselves and slimes be washed onto surrounding areas or into watercourses. This paper presents the argument that the results of contouring heaps are counter to good environmental practice. Calculations which have been made demonstrate that leveling and berming the heap tops as well as berming the edge of each lift or setback will effectively prevent water erosion and promote the growth of native plant species.

Jan 1, 1993

By N. W. Stump

New developments in on-stream analysis using immersed radioisotope gauges including results from plant installations are described. The control of grinding and flotation using a small digital computer has been complemented by this development. A control scheme for grinding which is based on maximum throughput at constant product size and preliminary work in flotation control are also outlined.

Jan 1, 1974

By S. A. Lolon, J. F. Brune

"INTRODUCTION In underground longwall coal mining, the mined-out areas or gobs frequently contain methane which can form explosive methane-air mixtures. Historically, there have been many events of mine fires and explosions recorded in the United States and other countries that have demonstrated the existence of such explosive mixtures, herein referred to as Explosive Gas Zones (EGZs), inside and around the perimeter of bleeder-ventilated longwall gobs (Loane et al., 1975; Lynn et al., 1986; Elkins, et al., 2001; McKinney et al., 2001; Dziurzynski and Wasilewski, 2012; Brune, 2013). The risk of mine explosions can increase if the EGZs migrate out from the gob into the surrounding mine entries. Several factors can induce EGZs outflowing from the gob, but the most common cause is the fluctuating barometric pressure. Atmospheric pressures change regularly every day but can fluctuate abruptly and become increasingly hazardous in adverse weather conditions. Other sudden pressure changes can result from roof falls, failing ventilation controls and fan outages. Any such fluctuation of mine ventilation pressure will disturb the pressure differential between the gob and the surrounding mine workings and may cause EGZs to outgas from the gob. The correlation between major mine explosions and abrupt barometric pressure changes has been studied and confirmed for explosions in coal mining countries including the United States, South Africa, Australia, and Poland (Hosler, 1948; Boyer, 1964; Kissell et al., 1973; Fauconnier, 1992; Hemp, 1994; Wasilewski, 2014; Belle, 2014; and Lolon, 2017). Disastrous mine explosions appear to happen more frequently during stormy weather, which, in the United States, typically occurs during the late fall and winter seasons. ROOT CAUSE AND EFFECT OF GOB BREATHING Gob breathing is the result of the pressure differential between gob internal and external pressures caused by external atmospheric pressure fluctuations that occur naturally as a result of gravitational and thermal forces in the atmosphere (Lindzen and Chapman, 1969). Other major and sudden pressure changes may be caused by fan failures, failures of ventilation controls or roof falls can also cause an unexpected gob breathing. Normal barometric fluctuations occur every day but usually do not pose an explosion risk as they occur gradually so gob pressures have sufficient time to equilibrate. More extreme fluctuations associated with cyclonic weather systems and storms often result in more rapid and larger drops or rises in barometric pressure (Hosler, 1948; Fauconnier, 1992). A study by Lolon (2017) found that the timing of historical mine explosions showed consistency with the occurrence of abrupt and intense barometric variations."

Jan 1, 2018

By Silvia Misk, Cristina Araújo, João Felipe Costa, Roberto Rolo

Linear estimation methods are widely used for resource evaluation. Among the existing linear estimation methods, ordinary Kriging (OK) was accepted as the best estimator to determine the average ore grade of each block. However, OK is inadequate for modeling small blocks in relation to data spacing, resulting in over-smoothed models. In this study, the results of the recoverable resource from the short-term model are compared to estimated models generated by the traditional method, i.e., OK, and non-linear methods. The conclusion is that non-linear methods improve the accuracy and precision of the long-term model when compared to the model generated by OK.

Jun 25, 2023

By S. B. Bhagwat

The United States has abundant coal resources that could last at least another century. and probably longer at present consumption rates. Geographically, the coal resources are distributed over the entire nation including Alaska, although there are no coal deposits in the highly populated areas on the two coasts. This allows free access to the coal, but makes transportation more expensive. Not all coals can be utilized equally because they differ vastly in quality. The sulfur content of coals, considered as the most detrimental acid rain-causing element, varies from as low as 0.3 percent in some areas of the western U.S. to 5 percent or more in parts of the Midwest. The chlorine content, which causes corrosion of plant hardware, also varies regionally. The 1990 amendments of the Clean Air Act of 1963 (CAA) require that emissions of sulfur be restricted and rolled back in two stages by the year 2000. There have been a number of reports expressing concern about the future of the industry in the states where high sulfur coal is produced. The remedies devised by the federal government and many coal-producing states in the past to "se-cure" the future of the regional coal industries have focused on the physical task of removing sulfur rather than the economic challenge of doing so at a cost that will enable high-sulfur coals to survive and compete. The past remedies, generally, were not specific enough to account for the characteristics of regional coal deposits and did not look at the coal market as an integrated national and international entity. The State of Illinois has, in recent years, taken a more comprehensive approach to the solution of the problem.

Jan 1, 1992

By R. A. Womack, Alex Ruzycki

Over the past six years, 4.5 million tonnes (5.0 million short tons) of gold ore have been heap leached at the Alligator Ridge Mine. Ore is leached in successive lifts, resulting in heap heights of 20 m (66 ft). Recoveries from each lift are determined through an extensive post-leach drilling program. The relationships between heap height, recovery rate, ore preparation, heap construction, and leach solution application are discussed.

Jan 1, 1987

By T. J. Fronapfel

Impacts to ground water from mining are being comprehensively regulated in Nevada through specific requirements for design, construction, operation, permitting and closure. This program is the nation's most comprehensive for control of activities at mining operations which have the potential to cause groundwater degradation. It encompasses virtually all types of facilities, including placer, physical separation, flotation, testing, leaching and milling. Minimum design requirements are established by regulation, and must be met by each facility. Site-specific monitoring requirements are established for each facility, and are heavily emphasized. Regulatory and technical requirements and relevant permit conditions are presented and discussed.

Jan 1, 1992

By A. D. Davis

The Bear Butte Creek watershed, in the northern Black Hills of South Dakota, shows the effects of past mining activities in the form of dissolved metals and arsenic in stream water. Bear Butte Creek, during normal flow periods, loses all of its discharge to sinkholes that recharge the Madison Limestone aquifer. This work focused on the geochemical transport and fate of arsenic and on understanding ground-water flow conditions in the Madison aquifer through development of a three-dimensional ground-water flow model that was coupled to a geographic information system (GIS). Stream sampling and discharge measurements helped determine sinkhole losses and loading rates. Column laboratory tests provided data on arsenic adsorption and the mixing of stream water with aquifer water, which also was simulated with the geochemical models, pHREEQE and NETPATH. The models and GIS can be updated with new information and will be useful in managing the water quality of the Madison aquifer.

Jan 1, 1997