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By Fathi Habashi

SOLVENT EXTRACI ION involves two operations: 1) Extraction The metal values in the aqueous phase are extracted by agitation with an organic solvent immiscible in that phase. The two phases are then allowed to separate; the aqueous phase is discarded or recycled and the loaded organic phase saved.

Jan 1, 1970

By Richard L. Bullock

INTRODUCTION TO COAL MINE PRACTICES To illustrate the trends and the proportions of the various methods used to mine coal underground, Fig. 1 is useful. However, of all the underground coal mining practices in the US, room-and-pillar mining still accounts for 96.5%. This percentage is divided as follows: conventional, machine cut-33.0%; conventional, hand cut -1.7% : and continuous mining-61 .8%. As was stated in Sec. 1, Chap. 7, the term "development" means different things to a coal miner and a metal miner. Though some of the ideas and concepts presented in the first two chapters of this section are valid for all types of mines, they apply particularly to mines using noncoal methods. In coal mines (and many other mines using coal mining systems) development refers to that phase of the mining cycle which advances several entries through the virgin seam, forming pillars by cross- cutting between the parallel entries. Because in the past, coal seams (as well as seams of potash, trona, oil shales, gilsonite, salt, and some uranium) have been much more uniform in their thickness, continuity, and quality, and because they often cover large areas, it has been possible to develop the room-and-pillar mine completely from a preplanned, systematic approach with a minimum of surface drilling information. As the better coal seams of the midwest and east are being depleted (or eliminated because of high sulfur), seams of poor quality and continuity will have to be mined. Also, seams that are not nearly so well known at greater depth will have to be taken as well as some of the steeply pitching and folded seams of the west. The American coal miner is only now feeling the need to do a much more complete job of prospecting the geology of the coal seams than he has ever done before. This is the only way that the risk of unknown rock conditions can be minimized. In many ways, surprises in the rock or coal seams are much more of a disaster to the coal miner developing a room-and- pillar mine than to his metal mining counterpart. Be- cause of the multiple entries, the complex set of the Federal Coal Mine Health and Safety regulations, and the totally dedicated design of coal mining equipment, coal mining systems do not have the flexibility to easily overcome changes in the seams mined or the rocks around them. Thus, if a wide parting of rock shows up unexpectedly in the middle of a coal seam entry being milled away by a continuous miner, it will either have to slowly "chew" through it, convert to a conventional mining system, or stop that particular entry. Likewise, if suddenly the coal disappears completely and in its place are the remains of an old creek bed, the "want" or "wash out" as it's called will usually have to be mined right along with the coal, by the same methods and with the same soft rock equipment, or the entry will have to be abandoned. For reasons such as these, coal seams today should be drilled from the surface just as thoroughly as the ore bodies in metal mines. Having once determined a more precise location of where the coal seams are located and which are suitable for mining, the engineer must still take a systematic approach to planning the mine as completely as possible. The initial series of entries must be planned to be driven either from the side hill portal or from the bottom of the shaft or slope. In either case, they should usually intersect the area close to the midpoint of the mass to be mined.

Jan 1, 1982

By H. Russell, N. DePriest, J. D. Quaranta

Valley-fill structures built of blasted rock overburden from Appalachian mountaintop surface mines pose many reclamation challenges. The steep mountainous terrain, short valley lengths, and straight stream channel profiles create significant challenges to implementing fluvial geomorphic landform design in terms of both form and function, and from a safety and constructability perspective. The fluvial geomorphic landform design approach balances erosive and resistive forces by considering long-term climatic conditions, soil types, slope profiles and vegetation types. Commercial geomorphic landform design software tools do not specifically analyze the stability and factor of safety for the computer-designed landform slopes. This research investigated slope stability parameters and factors of safety between a traditional valley-fill design with a geomorphic landform alternative. Slope stability assessments were performed on two profile geometries. Finite-element modeling of a permitted valley-fill and a geomorphic design alternative indicated that slope angle and internal angles of friction associated with the gradation of the overburden greatly affected the designed factor of safety for both designs. The geomorphic designed slopes yielded the highest factors of safety out of 14 models analyzed with all cases having factors of safety over 2.0. The high factors of safety are attributed to shallow slopes and beneficial surface and internal drainage.

Jan 1, 2014

By Jonathan K. Hrica, Brianna M. Eiter

The ability to identify hazards during a workplace examination is a critical skill for mineworkers to have in order to maintain a safe workplace. While research suggests that being able to successfully recognize hazards requires a complex set of competencies, it is unclear which competencies are most critical to adequately perform a workplace examination. This paper presents a hazard recognition competencies framework as an explanation of the competencies that affect mineworker hazard recognition. To better understand how the industry is selecting and preparing workplace examiners, researchers fromthe National Institute for Occupational Safety and Health (NIOSH) interviewed nine health and safety (H&S) professionals at surface stone, sand, and gravel mine sites throughout the USA. A primary purpose of these interviews was to verify the competencies included in the hazard recognition competencies framework and to understand why these competencies are critical. Finally, the results of this study are presented within the context of current NIOSH research findings related to hazard recognition.

Jul 27, 2020

By L. E. Allen, J. F. Abel, D. R. Morgan

The Waste Isolation Pilot Plant (WIPP) is a geologic repository for disposal of transuranic waste and is operated by the U.S. Department of Energy (DOE). The repository is located at a depth of 655 m in the Permian age salt beds of the Salado Formation, 40 km east of Carlsbad, NM. A key component in the design of the WIPP repository is the installation of concrete structures as panel seals in the intake and exhaust drifts after a panel has been filled with waste containers. The DOE has proposed several panel closure design modifications to the EPA. EPA approval of the changes is required since the details of the designs are specified in EPA’s final rule as a condition for WIPP certification. The Environmental Evaluation Group, in its role of providing technical oversight on the WIPP project, has evaluated the proposed modifications. An analysis of this evaluation is discussed.

Jan 1, 2003

By Ratnakar Singh, Raj Kishore, Kisor Kumar Sahu, Ranjeet Kumar Singh, Ganesh Chalavadi

The Falcon concentrator is capable of separating minerals in fine size classes based on their differential density. Separation of mineral particles depends upon the fluid flow characteristics and relative movement of particles in a fluid. In the present study, a fluid flow characteristic inside the Falcon concentrator was established through experimentation and modeling. The Falcon concentrator has two fluid entry points: (a) Fluid entering through gravity assisted feeding system and (b) Fluid entering through the fluidized hole on the concentrator wall. In order to identify the role of fluid entering the concentrator, a tracer was injected into the system. As per the tracer based experimentation, it was established that fluid entering through the gravity based feeding system is responsible for thin flowing film formation in the stratification zone where particles are stratified based on their relative density. The momentum balance and continuity equations were simplified for a high centrifugal force field, and the fluid velocity profile was estimated inside the thin flowing film. Estimated fluid flow profiles will help to simulate the particle trajectories inside the Falcon concentrator. The influence of rotational speed, fluid flow rate, and cone angle on the fluid velocity profile were investigated. Fluid thickness over the concentrator wall is also estimated, and it is typically of the order of ~150–200 μm.

By D. Bhattacharyya

The adsorption and desorption of gold cyanide by activated carbon is significantly influenced by particle size of the activated carbon particles and the chemical environment. A series of adsorption and elution experiments have been performed with ten different particle size fractions. The tests indicate that although the ultimate adsorption capacity is independent of the activated carbon particle size, the adsorption rate is strongly affected by the particle size. Further, desorption characteristics using traditional Mintek and atmospheric Zadra procedures reveal interesting trends with variation in particle size and will be discussed in this paper.

Feb 23, 2014

The National Mining Hall of Fame and Museum (NMHF&M) will celebrate its 25th anniversary on Sept. 22, 2012 when the 2012 class is inducted during a special ceremony in Las Vegas, NV in conjunction with MINExpo 2012. The NMHF&M will induct four men representing the equipment manufacturing, minerals exploration, copper and coal sectors of the mining industry. The diverse cross-section of mining industry giants joining the hall of fame include Glen A. Barton, J. David Lowell, Samuel Newhouse and John Cleveland Osgood. They will join 214 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame at the 25th Silver Anniversary Induction Banquet & Ceremony. These men were selected for being visionaries, leaders and ambassadors within their own sectors and across the industry at large.

Jan 1, 2013

By John C. Wangaard

A method of raising by use of a cage has been used with considerable success at the Cary Mine, Hurley, Wisconsin, on the Gogebic Range. The Cary Mine is owned by the Odanah Iron Company, Pickands, Mather and Company, Managers. This method is known to have been used previously at Tennessee Copper and probably in other districts. The Cary Mine was engaged in deepening the main shaft from the 34th to the 37th level. To accomplish this, and to facilitate development, a ventilation shaft 930 feet north of the main shaft was sunk from the 34th to the 37th level and crosscuts were driven on the 35th, 36th and 37th levels to the main shaft location, These levels are at 200 foot verticalintervals. All of this work was done in granite and the majority of the workings were not timbered. The next step was to get a raise through from the 37th to the 36th level, and from the 36th to the 35th level, which would later be stripped to full shaft size. Several methods of raising were considered including double-compartment cribbed and two single raises interconnected at regular intervals, but the cage method was chosen as it appeared to be a safe and efficient operation. The method in general consists in the use of a drill hole between levels through which to pass a hoisting rope to raise and lower a light cage.

Jan 1, 1958

By Timothy Batchler, Khaled Mohamed

Standing supports have been used in coal mines for decades to enhance roof support capability. Sometimes standing supports are used as a tool to resist the lateral movement of spalled ribs. Researchers from the National Institute for Occupational Safety and Health (NIOSH) are conducting a testing program for different types of standing supports (steel and timber) to investigate the effect of lateral loading on their vertical loading capacities and the factors affecting their lateral loading capacities. In this paper, the mine roof simulator (MRS), at the NIOSH Pittsburgh research facility, was used to determine the response of steel props to vertical and horizontal loadings. Finite element models (FEMs) were developed and verified using the tested steel props. To justify the testing program for testing standing supports with end-conditions of rock-like materials, the verified prop models were used to study the effect of a wide range of roof and floor materials (gray shale, shale, and claystone) on the critical buckling loads of the steel props. Also, several lateral loading scenarios were evaluated in which the steel props were laterally loaded at different heights. The critical buckling load for steel props setting up against a claystone roof and floor was found to be one-half of that shown by the MRS test where roof and floor platens are made of steel. Minimum prop performance was observed when the lateral load was applied at the mid-height of the steel prop, especially at small lateral displacement (less than 2 in).

Sep 10, 2022

By Armando Alatorre

The Republic of México is the world's largest producer of celestite/strontium carbonate and natural sodium sulfate. It is also a significant producer of flourspar, barite, graphite, sulfur, feldspar, salt and gypsum. New production may be brought on stream for borates, wollastonite, garnet, calcium carbonate and others. The country covers a geographic area of approximately 2 million square kilometers (760,000 square miles), and is divided into seven geological/geomorphological provinces. Less than 20 percent has been explored in detail for either nonmetallic or metallic minerals. This leaves large areas available for the discovery of world-class industrial mineral deposits. In addition to new deposits of those minerals currently being produced, there is exploration and development potential for borates, magnesite, rare earths, nepheline syenite, heavy mineral sands and numerous others.

Jan 1, 1995

By T. R. A. Davey, J. W. Sherman, B. J. DiSanto, G. Bjorling, G. S. Stacey, J. T. Cullom, R. L. Bird, S. E. Woods, J. C. Blair, Jorma Honkasalo

Most pyrometallurgical processes take place at high temperature with rapid chemical reactions when the elements and compounds are usually liquid or gaseous. Smelting. The classical method of obtaining a metal from its ore or concentrate is to smelt it in a furnace. The initial letter "s" of this word implies that, in addition to the physical process of melting, a chemical change also occurs. This is usually the reduction of metal oxide to metal by carbon or through a series of processes involving oxidation and reduction. Since solid-solid contact would not be sufficient to give a high rate of reaction, most smelting reactions occur by medium of two reactions involving solid-gaseous contact: where M represents a metal. The commonly preferred unit for carrying out these reactions is the blast furnace,1 which is a vertical shaft of refractory brick or water-cooled steel in which lumps of metal oxide and coke are fed at the top, and an air-blast is injected through tuyeres (water-cooled pipes) in the bottom. Molten metal is withdrawn from a pool at the bottom of the furnace, while N2, CO, and CO2 gases leave the top of the furnace, carrying some fine dust or fume with them, which

Jan 1, 1985

By W. P. Diamond, A. C. Smith, J. A. Organiscak, T. P. Mucho

The U.S. Bureau of Mines examined bleederless ventilation practices to evaluate their use as a spontaneous combustion control measure in U. S. coal mines. Results indicate that restricting airflow into mined-out areas (bleederless ventilation) is recognized worldwide as a spontaneous combustion control measure. However, ventilation practices commonly used to limit airflow to mined-out areas are not easily applicable to United States mining conditions, systems, experience and regulations. The types of bleederless ventilation systems used throughout the world and the spontaneous combustion risks associated with these systems are discussed. Primary design considerations for bleederless ventilation consist of the interaction of ventilation practices, methane drainage, ground control, seal construction and mine monitoring. Technological improvements needed for U.S. application of bleededess ventilation are also discussed.

Jan 1, 1995

By N. Harrigle, Tsutsumi

Very fine wet sizing of minerals such as kaolin, precipitated calcium carbonate, lime milk, and clay slip is a difficult process to achieve using standard vibrating screens. With particle sizes ranging in the sub-microns combined with the agglomerating tendencies of certain materials, screen blinding becomes a serious issue. Sizetec, Inc. has developed an innovative screening equipment to help solve this problem. The High Performer Screen uses powerful linear vibrations to help break apart agglomerated particles and prevent screen blinding. Optionally fitted with the Air Explosion Screen Cleaning System, compressed air can be periodically injected into the screen underflow chamber to clean the screen surface without the use of water sprays. This paper highlights some of the key features of the Sizetec High Performer Screen and describes typical performance that can be expected based on results from various trials conducted in the kaolin industries.

Jan 1, 2002

By Donald L. King, Frank A. Baczek

Sedimentation-based equipment is used in applications where separation of solids from liquid by gravity settling is desired. If a concentrated solids slurry is desired, the equipment is designed to "thicken"; if a clear liquid is desired the equipment is designed to "clarify." Thickeners normally handle higher solids loading rates than clarifiers, which usually process feed slurries containing low concentrations of suspended solids. Thickeners are therefore designed for heavier-duty requirements, and clarifiers have extra features to ensure more complete suspended solids removal. Major components (Figure 1) that are common to all sedimentation-based equipment are: tank, drive-support structure, drive unit and lifting device, rake structure, feed well, and a means of overflow and underflow withdrawal. Specific features are designed interdependently after the overall separation approach is defined conceptually. This conceptual approach is usually based on past experience or evolves from sedimentation studies conducted on samples of the slurry to be handled. Because many variations and combinations of components are possible, the overall conceptual approach has a number of possible designs that will accomplish the desired results. The final choice is based on practicality, potential for minimizing upsets, and cost.

Jan 1, 1986

By Z. Hyder, M. D. Cleason

"INTRODUCTION Mine Ventilation has come a long way over the years. The main purpose of mine ventilation is to keep conditions in the mine safe for the worker so that the mine will be productive and profitable. Technological developments to the mine ventilation system itself and the development of mining techniques have helped improve the safety and productivity of the miners and the mine. Most of the developments to mine ventilation and to safety devices came as the result of serious mining disasters. Another effect of those mining disasters, especially in the late 19th century and after, was legislation to set specific safety standards for mines, especially in the underground coal mines. This paper will focus on the connection between mines disasters and the mine safety legislations promulgated because of those disasters. A BRIEF HISTORY OF MINE SAFETY LEGISLATION Mine legislation has a long history in the U.S. dating back well in the 1800’s. However, mine safety legislation is considerably newer. In 1891, the U.S. Congress passed the very first version of mine safety legislations setting up minimum safety standards. By today’s standards, the 1891 legislation was incredibly basic (7). It took a series of horrific mining disasters for Congress to take action a second time. In 1910, Congress established the Bureau of mines. The role of Bureau developed and changed over next 60 years. In 1995, Congress voted to disband it (27). Initially the Bureau was only charged with investigating and coming up with ways to reduce accidents in coal mines. It was not until 1941, when Congress formally allowed Bureau of Mines’ Inspectors into the mines. In 1947, the Congress enacted and adopted a set of federal safety regulations for the inspectors to follow (1). Finally, in 1952 Congress granted the Bureau of Mines the authority to inspect the mines and to issue citations and/or orders of withdrawals. This act was known as the 1952 Coal Act and the penalties were limited to civil penalties. It would take a couple more iterations of mine safety legislation for monetary and criminal penalties to be introduced (10). Up until 1966, mine safety legislation was directed primarily at underground coal mines and surface coal mines. Congress passed the Federal Metal and Nonmetallic Mine Safety Act of 1966, thus providing a set of standards for all mines to follow (1). The 1952 Coal Act was amended again to be the Federal Coal Mine Health and Safety Act of 1969. This amendment was the beginning of modern mine safety legislation (13). In 1973, Congress created what can be considered the first ‘version’ of the modern day MSHA (Mine Safety and Health Administration). The initial version was the Mining Enforcement and Safety Administrations or MESA. Congress created MESA to act as the enforcement agency, relieving the Bureau of Mines of that responsibility so they could focus on their initial purpose, the development of countries natural resources (14). As mining industry grew, mine safety and health became a greater concern and priority. More efforts were put in legislating the industry. The Federal Mine Safety and Health Act of 1977 provided the platform for today’s mine safety and health legislation. Under the Federal Mine Safety and Health Act of 1977, also known as the Mine Act, MSHA came into being (1)."

Jan 1, 2016

THE FUTUREGEN CLEAN Coal project will be the recipient of $1 billion worth of federal stimulus money by way of the U.S. Department of Energy (DOE), which announced the commitment to the project. The money is expected to kick off years of further work that could finally see the project completed. One of the companies involved, Ameren Corp., said the $1.2 billion project ? which will include some private funding ? still has a number of hurdles to clear.

Jan 1, 2010

By Michel Dagbert

In the exploitation of porphyry-type deposits, the quality of the ore is mostly defined according to its grade. Besides the simplest distinction, ore-waste, several grade categories may exist and they correspond to the different ways in which the ore is further processed. At the time of mining the selection of the different categories is done from extensive information available from blast holes. But planning has to be done before this information is available and it is necessary for the geologist to forecast, from exploration and development data alone, the possible outcome of the selection done later on a block, a level, or the whole deposit and ultimately predict the ore reserves and value of the deposit. A good statement of this problem has been presented at the 1976 AIME annual meeting by Williamson and Hueller (1976). They have shown that, if the cut-off values are directly applied to the estimated grade of blocks, a gross overestimation of the recovered tonnage of ore (14%) will occur. This problem, now termed "the vanishing tons problem" (DaVid, 1977) seems to be common in many open-pit operations and it has been explained several times (DaVid, 1972; Huijbregts, 1975). In order to solve it l.Jilliamson and Mueller proposed a solution based on compiling masses and masses of blast hole data available from mined-out portions of the deposit. They derived empirical correction factors which provide for every block, given its estimated grade, the expected tonnage and average -grade of each category of material within that block. The purpose of our work is to repeat the same exercise but ignoring the blast holes data i.e. we want to derive the correction factors from the only DOH data. Doing this, we are more in the real conditions where the valuation of the mine and are reserve analysis has to be made before production actually starts. Two possible ways to achieve this goal will be investigated and the emphasis will be on recently

Jan 1, 1977

By C. L. Sarff

[Automation has become a word that means many things. To management it is the end of the rainbow; you push a button and all your problems are solved. To the working man it is a horrible monster that is taking his livelihood away. To the maintenance man it is a complex that overwhelms him when he thinks of trying to find the trouble when the machine is not operating, properly. Automation has been with us in the coal nines for many years. Long before my time you were using float switches on mine sumps to control the level of the water. That?s automation in the truest sense of the word, but we call it automatic and think nothing of it. If we use the word automatic instead of automation your mine electrician and mechanic will take hold of the problems in stride.]

Jan 1, 1962

By T. Petrov

This study was performed to analyze the behavior of the blowing curtain face ventilation system modified with a specially designed regulator, called Wing Regulator. The purpose of the regulator is to extend the airflow penetration depth toward the face and allow effective face ventilation at curtain setback up to 13.7m (45ft) from the face. A small scale model of the Wing Regulator was successfully tested in the Mine Ventilation Laboratory at the University of Kentucky. Then a prototype of the proposed regulator was tested in full-scale in mine environment. Series of three dimensional simulations were performed to support this research using validated CFD code. This paper presents results of the performed studies and discuses the advantages of using the Wing Regulator. Presented information relates to the US Provisional Patent Application No 61/818,112.

Feb 23, 2014