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By M. C. Radomsky

Approximately sixty, small, surface coal mines in Pennsylvania participated in a program designed to improve safety performance in the workplace. The method involved the use of safety sampling and observation to assess the safe standards of worker behavior and work conditions. Data were collected through the use of operation-specific, on-site safety records covering seven major occupational units. Workplace events observed (acts and conditions) were assigned a hazard classification; feedback, both immediate and delayed was initiated to improve safety performance. The experiences drawn from this pilot project have proven the need to continue to pursue this behavioral approach; however, a stricter methodology needs to be adopted in the collection and analysis of data.

Jan 1, 1987

By J. Stowe

While there has been continual improvement in the models for predicating deposition velocity and pipeline friction losses, the fundamental design philosophy for tailings pipelines has remained the same over the previous three or four decades: design the tailings pipeline to operate in turbulent flow without a deposit on the pipe invert for all expected process conditions. Recent improvements in the understanding of slurry pipeline flows allows for the design of pipelines operating with a deposit on the pipe invert, allowing the system to operate at moderate velocities for high flow rates, optimizing system energy requirements and maximizing pipeline wear life. Tailings pipelines are increasingly operated at higher solids concentrations where there is a greater likelihood the pipeline will operate in laminar flow due to the higher tailings slurry rheology. Historically, slurry pipelines have been operated in turbulent flow. We now know that laminar flow pipeline operation is possible as there are several operational laminar flow tailings pipelines. While our understanding of laminar flow slurry pipelines is not complete, recent research provides guidance on how to approach the design of these pipelines. New sensor technology has led to the development of an instrument that provides reliable indication of bed deposit height within a pipeline. This technology is particularly helpful in operating pipelines with a deposit and has application in better understanding the operation of laminar flow pipelines. Failure of tailings pipelines can result in consequent damage to surrounding structures and unacceptable spillage into the environment. Modern pipeline leak detection technology allows operators to better manage this risk by ensuring safe and reliable operation of tailings pipelines. This paper provides an overview of the each of the above advances in the design and operation of tailings pipelines. OPERATING TAILINGS PIPELINES WITH A DEPOSIT Tailings pipelines, and slurry pipelines in general, are typically designed to operate without a deposit on the pipeline invert. Meaning, the minimum operating velocity exceeds the turbulent deposition velocity. This approach has been adopted due to concerns regarding potential blockage of a pipeline operating with a deposit. Figure 1 shows a typical design duty envelope for a tailings delivery system as a function of solids throughput and solids concentration by mass. If the pipeline is designed to operate without a deposit at the lowest duty flow rate (4,480 m3/h), the operating velocity at the highest duty flow rate (6,590 m3/h) is about 1.5 times the deposition velocity. Considering that the pipeline wear and energy requirements are roughly proportional to the square of operating velocity, this results in an operationally inefficient system when the pipeline is operated close to the maximum design flow rate. Most systems tend to operate at maximum throughput after post-startup debottlenecking optimizations. Alternative Approach An alternate design approach is to ensure the pipeline operates without a deposit for the nominal flow rate and accept that a deposit will form when operating at lower flow rates. This results in the selection of a larger diameter pipeline, but there are significant benefits in terms of reduced energy requirements and lower pipeline wear.

Jan 1, 2019

By Edward M. Downs

This paper is a brief review of the lubrication requirements of enclosed gearing on earth moving equipment, particularly as they apply to intermediate and large draglines and shovels used in open pit mining operations. It discusses the requirements of spur, helical and herringbone gearing in both horizontal and vertically mounted applications. The effects of base stock, oil viscosity, additive treatment, quantity of oil and method of application are considered. In addition, a newly designed circulating oil system for enclosed swing gear cases and the reasons for its development are discussed.

Jan 1, 1968

By Andrew Griffiths

The emphasis in the title of this paper should be placed on the world "Total", since the detoxification of cyanide in its free and weakly-complexed form with H202 has already found application in many areas, including the treatment of mining effluents. One of the most common forms of cyanide found in gold-mill effluents is hexacyanoferrate (usually ferrocyanide), which is included in measurements of total cyanide but is too stable to be oxidized by H202 or any other conventional oxidizing agent. This has led to the view that H202 cannot be used to detoxify effluents containing hexacyanoferrates, when a limit has been set on total cyanide. A process is described in this paper which does meet this requirement, and which has already been demonstated in two Canadian gold mills. Before describing the new process, the terms "free", "total" and "weakly-complexed" cyanide will be defined as they are used in this paper.

Jan 1, 1998

By Rob Dorey

The disposal of mine waste continues to be one of the main controlling factors in the economics and feasibility of project development. Particular to gold and precious metal mining, waste disposal is further complicated by the environmental and political implications of the use of cyanide. Regulatory compliance criteria have partially dictated and can be anticipated to further dictate the approach and methods of tailings disposal. To develop practical, economic, and environmentally acceptable tailings disposal systems within these criteria requires the use of common sense approaches and the application of available technology. Waste disposal is typically considered during the pre-feasibility stages of project evaluation. At this time, the main emphasis is on the economics and practicality of extracting the metal values from the ore. Frequently, the result of this is that the nature of the tailings and the ability to dispose of the tailings is prejudged. It is also frequently the case, however, that during the feasibility stage and project permitting, the requirements for tailings disposal become paramount.

Jan 1, 1998

By R. Ramesh

Understanding the nature of coal surface heterogeneity is a prerequisite to accurate characterization and efficient control of coal surfaces. New techniques based on the centrifugal immersion of particles from the liquid/ vapor interface and film flotation have led to independent estimation of surface energy distributions in individual coal particles. Changes in the distribution of surface sites due to oxidation and polyacrylamide adsorption on coal are studied here using the above techniques. New information on -possible conformations of adsorbed polymers is also obtained.

Jan 1, 1989

By R. P. Upadhyay

The Deserado Mine, located in northwest Colorado, is an underground coal mine designed to produce 1.225 million tons (1.35 million short tons) of clean coal per year for the Bonanza Plant located in northeastern Utah. Coal is transported to the power plant via a 61 kilometer (38 mile) captive railroad. Most of the surface facilities and the stationary underground equipment is controlled and continuously monitored by the computers located at the surface control room. In addition to system control, the computer also continuously monitors vital environmental conditions using sensors located at various critical locations underground. The system's advantages are increased mine productivity and safety.

Jan 1, 1988

By Jr. Mason

Eminent Domain is the power of the government or municipality to take property for public use without the consent or acceptance of the owner. Typically the agency taking the property will make an offer on the property, hoping that the owner will immediately accept and allow work to begin. If a mutual resolution regarding the property value cannot be reached, however, the municipality will condemn the premises and institute a condemnation action in a court of law, which is when the problems begin. The power of the government to take the subject property is limited by the Federal and State constitutional duty to pay "just compensation" for the property.

Jan 1, 1989

By Juan L. Yarmuch, Gonzalo Sepulveda

Medium- and short-term mine planning holds immense significance in optimizing production and resource utilization. It serves as a vital link between the long-term strategic plans and the day-to-day operational activities of a mine. In this context, a mathematical formulation is proposed to incorporate mining width constraints into the production scheduling process, aiming to maximize the net present value (NPV) of the schedule while ensuring enough room for the operation of mining equipment.

Jul 1, 2024

By D. C. Moore

The decision to proceed on a "fast track" construction project is not" without risks as well as rewards. An understanding of some of the risks prior to start of the project will maximize the rewards. This paper describes the research, development, procurement, engineering and construction of the Asamera Minerals cannon Mine concentrator. This fast track project was accomplished in 20 months. Special attention is paid to the risks encountered and the steps taken to ameliorate them.

Jan 1, 1988

By M. Misra

The interaction of xanthate with SO2 in the flotation of sphalerite and chalcopy.ite is discussed. 'The SO depression of sphaledte is due to the decomposition reaction of xanthate by SO2 The decomposition reaction is dependent on the cole ratios of xanthate/SO2, oxygen concentration and pH. Xanthate adsorbs at a faster rate by chalcopyrite than sphalerite. The faster rate of xanthate adsorption by chalcopyrite and the specific action of S02 on the surface of chalcopy.ite facilitate the selective separation of chalcopyrite from sphaledte.

Jan 1, 1989

By B. T. Dawson

In today's work world, constant changes are a fact of life. Downsizing and technological advances are two of the most prominent concerns for employers and employees alike. In this article, the author addresses some of the emotional consequences of these changes and offers a new, empowering perspective for coping with them.

Jan 1, 1998

By A. Johnson

When are SMART transmitters the smartest choice? To answer this question requires a closer look at SMART transmitter technology. It is necessary to understand this technology in order to recognize how it can best be utilized to give the greatest value for the application. And, once the decision to buy transmitters has been made, it becomes a question of whose SMART transmitter to buy. For, although the under-lying technology is similar, the differences that exist in how the technology has been implemented can make a dramatic difference in the end result. What prudent users of SMART technology do is to analyze their needs by application before making their buying decision.

Jan 1, 1988

By J. H. Mackey

"Where can I obtain a reclamation bond today?" "Who is writing your bonds?" These questions are common and heard frequently. The fact that the Society of Mining Engineers has determined that two of the five environmental topics reviewed at the 1989 Annual Meeting relate to reclamation bonding indicates to me that those who are involved in the coal industry, no matter what capacity, remain very cognizant of the reclamation bonding dilemma.

Jan 1, 1989

By R. Sandefur

Recent advances in personal computer technology allow movies of various types to be made and displayed on PC and Macintosh computers. An interesting application of this movie technology is animation of computerized geological models. These movies, which can be most easily constructed along rows, columns, and benches of block models, allow an ore body to be more easily and quickly visualized than the traditional method of flipping back and forth through various sections.

Jan 1, 1994

By A. A. Jonke

The combustion of fossil fuels in a fluidized bed of calcined limestone particles is a potentially efficient and economically attractive process for the generation of steam for electric power production and other uses. The process results in greatly reduced emissions of both sulfur oxide and nitrogen oxide pollutants. Development work, evaluations and design studies are being carried out by various organizations under contract with the U. S. Environmental Protection Agency and the Dept. of Interior (Office of Coal Research). The AEC's Argonne National Laboratory is one of the principal participants in the development program under interagency agreements with EPA and OCR. This paper covers the principal reasons for developing fluidized-bed combustion, its advantages and disadvantages over conventional combustion methods, and some of the potential applications of the process. The participants in the multi-organizational program, the sponsoring agencies, the general status of development of the overall project, and the chief program areas that still require resolution are discussed. The main features of the program of work at Argonne National Laboratory and the results achieved so far are also included.

Jan 1, 1974

By Stanley Kesler

The first of two initial 650-mw units of the Paradise Steam Station, located on the banks of the Green River in the south-central portion of the western Kentucky coal basin, is scheduled for operation in late fall of 1962. Location of the site is shown on the map of figure 1. This plant will be the eighth, large-capacity,, modern station built by TVA in a series starting with Johnsonville, operated first in 1951. During that period of 10 years,, unit sizes have increased from a capability of 125 mw to 500 mw at the recently completed Widows Creek Unit 7 addition and at Paradise to 650 mw. This new unit will take its place in a power system that serves an area of some 80,000; square miles with a present installed capacity of over 12,000 mw. Upon completion of the Paradise units and other additional hydro and steam units presently under construction, the system capacity will have reached over 15,000 mw. Projected load estimates indicate that this system will provide a margin' of slightly under 10 percent of dependable capacity above peak demand at that tire. One Paradise 650-mw unit at that time will represent approximately 4 percent of the total system installed capacity.

Jan 1, 1962

Caterpillar recently held two, two-day demonstration programs for its mining customers. The event, billed as MineDemo by Caterpillar, consisted of two sessions held on consecutive weeks at the company's Tinaja Hills proving ground south of Tucson, AZ. The program included several classroom sessions that focused on Caterpillar equipment applications, including the VIMS (vital information management system) and the CAES (computer-aided earthmoving system). Also included were field demonstrations and the opportunity to test drive mining-related heavy equipment, including dozers, trucks, graders, shovels and loaders. Featured at the event were the recently upgraded 785, 789 and 793 C-Series trucks. Caterpillar recently announced the availability of the 136-t (150-st) 785C and the 177-t (195-st) 789C. The upgraded haulers have replaced the respective B-Series models. The 218-t (240-st) 793C was introduced in 1996. It, too, has been upgraded but retains the C-Series designation. While attending the press event, the author had the opportunity to test drive the 793C at the Tinaja Hills test site. It was amazing how well the machine handled. The operation was smooth and the braking system was precise. The cab was extremely comfortable. To see a C-Series truck in action, the author also visited Newmont Mining's Mesquite Mine, located in Cali¬fornia, across the border from Yuma, AZ. The Mesquite Mine operates a new model 785C truck. At the mine, temperatures have been measured as high as 58° C (138° F) in the pit. Needless to say, the ability to operate dependably in extreme heat is an important consideration for the mine operators. An interview with the driver and later with management confirmed that the 785C has worked out well. The driver praised the comfort of the cab and the ease of operation. Management reported significant fuel savings and was impressed by the truck's maintenance features.

Jan 1, 1999

And a new generation of safety culture experts are telling mining companies how to use it: It is a situation that is still too common in the mining industry: the latest personal protective gear is in place. The safety rules are known and followed. And then, in a moment of inattention or carelessness, a mistake is made and someone gets hurt or killed. Common wisdom claims that such accidents are impossible to eliminate entirely. Mining is dangerous, and some miners will always be hurt and killed. An increasing number of mine safety experts, however, reject the common wisdom. A year with zero mining deaths is possible, they say; with the use of one of the newest weapons to the mining industry in the safety war: the concept of safety culture. Safety culture refers to the set of attitudes, beliefs, perceptions and values that influence safety in the work environment. It is also sometimes called the way an organization behaves when no one is watching. Robert Peters, of the Office of Mine Safety and Health Research (OMSHR) at the National Institute for Occupational Safety and Health (NIOSH), describes safety culture this way: ?It?s what?s believed on a day-to-day basis. For example, if a miner sees a workplace hazard and he truly believes that his boss wants him to identify the hazard and bring it to the company?s attention, that would be an example of a positive safety culture.?

Jun 1, 2010

By M. L. Sharrah

Communication about the energy problem has come at us in great profusion during the last couple of years--reports, speeches, editorials, advertisements--and events. Events such as the Arab embargo on oil exports which vividly demonstrated the world's dependence on oil, a finite and nonrenewable resource. And the three-fold increase in the price of oil which provides a constant reminder of the political and economic implications of dependence on foreign oil. A distinction among countries exists today which was almost inconsequential two years ago--the oil exporting nations and the oil consuming nations. The only rational way for the consuming countries to lessen the political and economic clout of the OPEC group is to reduce their dependence on oil. The United States is capable of playing a significant part in such a move for several reasons.

Jan 1, 1975