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By D. J. Turk

Faced with decreasing production from the gold heap leach operation, Robinson implemented a drilling and blasting program on the leach pads in 1993. This program offset some of the negative effects of low ore permeability and short circuiting of leach solution that resulted in lower than optimum recoveries. The drilling and blasting program created new solution flow paths and increased gold recovery. Production and pulp assays at depth intervals, prior to and following drilling and blasting, reveal the degree of short circuiting and benefits of the program.

Jan 1, 1995

Laboratory tests were conducted in a full-scale continuous miner test gallery to evaluate resulting dust levels for changes in face airflow, spray water quantity and pressure, and mining height. The minimum and maximum values tested for each parameter were as follows: airflows between 1.42 and 6.14 m3/sec, water flows between 56.8 and 132.5 lpm, nozzles pressures between 413 and 1379 kPa, and mining heights between 1.52 and 2.74 m. Each of these parameters were evaluated for four common spray system designs. Respirable dust samples were collected in the operator's cab on the miner and in the immediate return. Second-order polynomial models were used to represent expected dust levels and multiple stepwise regression was used to identify significant control parameters for inclusion in the models. Separate models were developed for dust levels at the operator and return locations and for each individual spray system. Interaction between control parameters and curvature effects were found in most models. The analysis indicated that at the operator location, airflow and mining height had the most significant impact on respirable dust levels. In the return, airflow and water pressure were typically the most significant parameters. The models developed for each spray system design can be used by mine operators to guide application of control parameters for a variety of operating conditions and mining heights.

Jan 1, 1994

By M. Akser, M. Tomas

Six Sigma is a methodology that uses a structured and disciplined approach to improve process performance (higher throughput, better recovery, lower cost, shorter cycle time, etc.). Specially trained people called “black belts” lead and manage Six Sigma projects. Black belts, with assistance from their team, ensure that projects follow the DMAIC (define, measure, analyze, implement and control) process phases. Timely completion of each project, with measurable deliverables, is key to Six Sigma’s significant financial success. Implementation of Six Sigma has been growing in recent years in a wide range of industries. The heavy mineral industry, like many other industries, could benefit from what Six Sigma has to offer. Specific Six Sigma project examples are included from DuPont’s Heavy Mineral Production Plant in Florida.

Jan 1, 2005

By Walter E. Cook

BOB FALCONER: Without further ado I'm going to introduce our first speaker, Walt Cook. Walt is president of Strata Resources and is here with his business partner Joe Nenni. Joe would you stand up here. You'll be on the tag-team with Walt. Walt and Joe are in a consulting business associated with coal as well as metal and nonmetal industries. Their presentation will be on gainsharing. WALTER COOK: How many of you have gainsharing plans in place currently at your location? [show of hands] A considerable number-more than about half the room. Of those plans, how many of them do you consider as meeting your needs and being successful? [show of hands, far fewer, general audience laughter] You have all at least heard the word "gainsharing." Some of you undoubtedly aren't quite sure what gainsharing is, while others obviously have gainsharing plans in place and are looking for ways to improve them. In the short time I have now I'll be able to give you a precursory look at gainsharing and some brief ideas on where to look to improve your current plans. Over the years, I've found that it is often best to explain gainsharing by comparing it to other forms of employee compensation

Jan 1, 1998

By P. Zhang

The Crago “Double Float” process is widely used in upgrading phosphate ore. This process is inefficient, as it floats about 30-40% of the sands in the flotation feed twice and requires a deoiling step. This paper summarizes several research projects on improving phosphate flotation. The University of Utah investigated a new flotation chemistry for efficient flotation of phosphate in a single step. The Florida Institute of Phosphate Research developed several single-collector, all-anionic flotation flowsheets using various sizing schemes. In addition, Eriez invented the HydroFloat separator, which demonstrated great potential for processing coarse flotation feed in one step.

Jan 1, 2004

By Bruce W. Cavender

There is a tendency for managers of mining companies to regard the performance of a process plant as essen­tially fixed, with only incremental improvements to be realized by optimizing individual unit operations. However, a number of op­erations management methods are available that will substantially improve plant performance, through both productivity increases and cost reductions. Known collectively as "world-class manufac­turing" techniques, these include total quality control, just-in-time production and inventory management, the systematic develop­ment of innovative plant practices, and progressive management accounting and business control systems. The implementation of these techniques by plant managers and operators will enable the plant's performance to exceed levels that are currently believed to be maximized.

Jan 1, 1993

By R. J. Snoby, J. K. Alderman

Although once fairly common as a method of coal preparation in the United States, dry cleaning has virtually disappeared. Low-rank coals used for power generation in the western U.S. are suited for dry cleaning because water has limited availability in the American west. Surface moisture added through wet cleaning offsets energy improvement achieved from mineral matter reduction. Information will be presented on the commercial application of dry cleaning in North America, the historic development and current status of the technology, and the introduction of modern processing theory and control technology to the design of dry cleaning equipment and plants.

Jan 1, 2001

By S. G. Britton

Thin seam mining presents unique challenges when management or economic conditions require significant productivity increases. These challenges are increased depending upon the presence of various external factors such as labor unions, Federal and state regulations, and market characteristics. This paper explores the turn-around situation occurring at Tanoma Mining Company (TMC), a medium-sized underground coal mining company in central Pennsylvania, USA. Using a systematic approach of improving management controls and direction, labor relations, and communications, coupled with an intensive upgrade/rebuild/replacement program for equipment and systems used at the mine, TMC has begun reversing its' cashflow position from negative to positive within two years.

Jan 1, 1991

By Scott G. Britton

Thin-seam mining presents unique challenges when management or economic conditions require significant productivity increases. These challenges can be further amplified depending on such factors as labor unions, federal and state regulations and market characteristics. This article explores the turnaround situation occurring at Tanoma Mining Co. (TMC), a medium-sized, underground coal mining company in central Pennsylvania. The company has used a systematic approach of improving management controls and direction, labor relations and communications to improve its cash flow from negative to positive within a projected five-year span. An intensive upgrade-rebuild-replacement program for mining equipment and systems has also been established to support other management activities. Discussion Thin-seam coal mining is an industry within the broader industry of coal mining. Thin seam mining faces the same cost pressures and engineering problems as its higher-seam competitors, without the advantages of moving volume per foot of extracted material. To stay at economic parity with others requires additional creativity within the management team to extract higher productivity gains from the existing workforce and mining systems. The Tanoma operation is a deep mine in Indiana County, PA, about one hour northeast of Pittsburgh. Coal is extracted from the Lower Kittanning "B" seam. It lies about 91 m (300 ft) below the surface and averages 0.9 m (I ft) in height. Continuous mining units using mobile bridge conveyors or shuttle cars

Jan 1, 1991

By Richard L. Ash

Less than optimum production in mining always results when poorly blasted material is provided at loading points. More often than not the cause is due to blasting founds that fail to fully control and utilize explosive energy. In many cases the problem exists because too few blasters understand how blastholes actually break rock and recognize that blasting is a three-dimensional process in designing their blasts. To better understand how blasts can be more effectively designed the two major rock breakage processes are described. In addition, the respective contributions of the borehole and detonation pressures are defined as are the specific roles of the several important blasting design variables. The concept of stiffness as an engineering principle and its significance in blasting design is introduced for explaining the breakup of rock. Basic guidelines for affecting control over fragmentation and side effects like over-break are offered.

Jan 1, 1975

By J. R. Patts, J. P. Rider, J. A. Organiscak, A. B. Cecala

"The U.S. National Institute for Occupational Safety and Health completed a 15-month study at an underground limestone mine crusher booth that evaluated three research parameters: (1) the effectiveness of a filtration and pressurization system for improving the air quality inside the operator booth, (2) the relative effectiveness of ? > 99 and ? > 95 experimental prototype filters in the system, and (3) the performance of three different cab pressure monitoring devices. The protection factor was quantified monthly using particle counters in the respirable dust range of 0.3 to 1 µm particle size, and gravimetric dust samples were gathered at the beginning and end of the overall study. Under static (closed-door) conditions, the filtration unit offered a gravimetric calculated protection factor between 10 and 31, depending on the filter type and loading condition. The monthly particle counting analysis shows that the ? > 95 filter offers a protection factor nearly five times that of the ? > 99 filter, where n = 15 samples. The booth pressure monitors were tested and proved to be a valid indicator of system performance over time. IntroductionDesigned and installed correctly, enclosed cabs, operator booths and control rooms offer mine workers protection from noise and physical hazards, such as flying rock and debris, as well as a more comfortable environment in regards to temperature and humidity (Organiscak et al., 2016). While it is easy to quantify the operation of a cab’s air-conditioning unit by measuring the temperature, or observe whether the cab offers protection from flying debris, it is somewhat more difficult to quantify its performance in reducing respirable dust hazards.The U.S. National Institute for Occupational Safety and Health (NIOSH) has been conducting applied research to improve the air quality inside the enclosed cabs of mobile equipment, resulting in the mathematical modeling of enclosed cab filtration systems (Organiscak and Cecala, 2008). The same principles that govern the performance of filtration systems on mobile equipment are applicable to stationary enclosures such as operator booths and control rooms (Noll, Cecala and Hummer, 2015). While stationary enclosures are similar to mobile cabs, the work area can be significantly larger. Workers in booths and control rooms also tend to stay within the enclosure for a greater percentage of the day as opposed to workers on mobile equipment who enter and exit frequently."

Jan 1, 2018

By J. A. Dlas Lima

Alunorte is a metallurgical-grade alumina refinery located in northern Brazil. This plant which was designed to produce 1.1 million mtpy of calcined alumina, started operation in July 1995. A process information system was installed before refinery start-up. It has been a main factor in process improvements, which resulted in an increase in production from 1.1 to 1.5 million mtpy. This system has been particularly useful for analyzing data and allowing retrieval of data by process engineers. This paper describes how a quality monitoring system to evaluate all aspects and stages of production, as well as alumina silo level and blending percentage, was developed. This system was designed to give support to ISO 9002 certification, which happened in December 1998. The quality monitoring system was developed using Microsoft Excel 7.0 and makes extensive use of VBA macro. The primary users of the system are shift foremen, managers and engineers, who use it to track the process and avoid variations in alumina quality.

Jan 1, 2000

By L. B. Hales

Expert control of grinding and flotation plants has been successfully used in the minerals industry since the 1970?s. The earliest of these systems were written in a hard-coded fashion in FORTRAN, BASIC or Pascal. Second generation systems were built using the first experimental expert system shells that were being developed in the artificial intelligence community. Later systems were deployed in expert systems designed for real-time processing plants that also include the ability to model the process with neural network models and optimize setpoint selection through the use of genetic algorithms. [1,2] In spite of the fact that significant performance increases have been achieved using these systems they are not perfect and can be improved. They suffer from the static nature of their rules and to a degree the process models. There is an opportunity to further increase system performance by systematically taking advantage of the tremendous amount of data produced by the expert system to improve the design, the heuristic rules, the model topologies and the use of the models. Data mining refers to extracting or mining knowledge from large amounts of data where the objective is to automatically analyze, classify and summarize the data to automatically discover and characterize trends in it and to automatically flag anomalies. [3] Clearly, modern process control systems are capable of collecting vast amounts of data. Without a doubt, these data contain important information on the operation of our plants and their ultimate optimization. Coupling the information mined from these data with Expert Control Systems should produce more effective control and greater knowledge of the grinding process and the flotation process. Now, with the advent of effective monitoring of entire minerals plant electric consumption it is possible to not only optimize plant production in real-time it is possible to analyze total plant electrical consumption and incorporate it into the plant control logic thereby improving the overall plant economic performance. This is particularly important with the ever more complex power contracts that plants operate under.

Jan 1, 2012

By T. R. Ley

"RELIABILITY & SAFETY – TOGETHER. REALLY? I was starkly reminded of the challenges facing by the coal industry while talking with a number of senior mining executives. One said to me: “Safety is the #1 priority in our organization but of course, dollars are very, very important!!!” A coal mine worker at the Bluefield Coal Show claimed: “We know our equipment is bleeding hydraulic fluid all over the place but all that matters is getting the coal out”. We all understand. We want our people to go home safely at the end of the day but the coal industry is bleeding – fluids, dollars and real blood. An issue getting plenty of buzz these days is equipment reliability – in mining too! Achieving an optimal return from the massive investments in equipment is a critical requirement for success within a capital intensive industry like coal mining. You can cut costs by scrimping on maintenance, scavenging used parts and downsizing. Or, you can save money by being smarter with your asset management processes. Can we afford to spend money on both safety and reliability? Is one more important than the other? Many leading edge companies from a variety of industries will tell you that you can’t just cost-cut your way to profitability - or even survival. You need to systematically improve the effectiveness of your business. Do reliability and safety both have a place in improving the performance of the coal industry? According to Ron Moore, of The RM Group, the answer is emphatically YES! Ron says: “If you believe in safety, then you MUST believe in reliability and, more importantly, have the appropriate policies, systems, practices and measures in place. If you want lower costs, you must get your processes right. Simple cost cutting will remove resources from your system without changing the underlying system design, and performance will likely deteriorate.” Figure 1 shows the 5+ year results of a large manufacturing company. When plants are running well (high Asset Utilization), then injuries are less likely. Figure 2 plots data from a number of manufacturing plants. If you want sustainably lower costs get your reliability processes right. But these are manufacturing companies, not coal mining operations! It doesn’t matter. The fundamentals still apply. Mining industry thought leaders tell us that manufacturing is 20-30 years ahead of us and we need to learn from them – and do so quickly. Leading companies, no matter the industry, think in terms of operational excellence. They see this as the meshing of people, process and technology to achieve optimal results. Safety and reliability go hand-in-hand. People and equipment are different – but only to the extent that each requires its own relevant, but related, policies, practices, systems and metrics to achieve effective performance."

Jan 1, 2016

By A. Hammons

Automated temporary roof support (ATRS) systems have been incorporated into roof bolters since the 1970's. During roof bolting, many injuries have occurred from large pieces of draw rock falling inby the ATRS beam and tipping back into the operator's area. Other injuries have occurred due to smaller, sharp rocks falling onto the operator's hand and arm during initiation of roof bolt drilling. These injuries are attributed to weak immediate roof, sometimes called roof skin failure. Even though ATRS systems support the roof and provide a measure of protection against roof skin failure, additional hazards sometimes do exist immediately inby and outby the supported roof. Design innovations such as the ATRS mounted rocker pad deflector systems have been designed to improve the roof bolter operator safety. This paper will inform the reader of the hazards, machine evolution through different design solutions, and the current state of the art in preventing roof skin failure injuries when roof bolting.

Jan 1, 2009

By T. Burchett, F. Stanley, K. McGough, G. Luttrell

The vast majority of U.S. coal preparation plants utilize screen-bowl centrifuges to dewater their fine clean coal products. In light of this popularity, researchers at Virginia Tech have engaged in a variety of laboratory and industrial field test programs to develop technological enhancements that have the potential to further improve the performance of this important solid-liquid separation process. These enhancements, which include simple design modifications and new reagent packages, have been shown to significantly improve solids recovery and reduce product moisture in several experimental trials.

Jan 1, 2006

By H. Walqui, G. Rajala, G. Suardini

The Empire mine began operations on 1963. Low grade Magnetite ore is processed to produce iron pellets for blast furnace feed. Three expansions were added to the original plant and several equipment upgrades have been completed to improve the plant performance as the ore characteristics have been changing through the life of the mine. Size reduction is carried out by two grinding stages, the first one using autogenous grinding and the second one using pebble mills. Pebble crushing is also used to break the critical size fraction and increases primary grinding capacity. This paper describes changes in the configuration of the grinding circuits that have helped increase plant throughput and reduce power consumption by more efficiently utilizing assets available. Understanding the different components of the size reduction circuits and plant sections has allowed shifting part of the load from one section of the plant to another without affecting plant throughput.

Jan 1, 2007

By Doandy Yonathan Wibisono

Shotcrete is a versatile and widely utilized rock support material in mining and civil engineering projects due to its adaptability, strength, and efficient application. It immediately stabilizes rock surfaces, effectively controlling loose materials and preventing rockfalls in underground excavations. This paper focuses on assessing and analyzing data from observations of nozzlemen (shotcrete sprayers) during primary ground support activities in an underground mine. The study highlights the importance of nozzlemen’s skills in ensuring the quality of shotcrete application, which is critical for underground mining operations’ structural integrity and safety. A comprehensive training program and field support were implemented to enhance the nozzlemen’s proficiency. The training set covered theoretical knowledge and practical techniques to improve shotcrete application daily. Proficiency improvement was assessed using quantitative metrics, with rebound percentages decreasing by 5–14% as nozzleman competency increased. The results of this initiative showed significant improvements in shotcrete quality, including increased efficiency, reduced waste, and fewer reworks or rehabilitations. The findings aim to contribute to a broader understanding of best practices in shotcrete application and nozzlemen training, ultimately enhancing ground support application measures in the mining industry.

Feb 1, 2025

By G. D. Trump, F. L. Stanley

Spirals have become one of the most popular methods for treating fine coal. Unfortunately, spirals tend to produce an undesirably high specific gravity cut point and often misplace significant amounts of coal and/or rock. In the present study, a process-engineering tool known as linear circuit analysis was used to identify problems with traditional spiral circuits and to suggest alternative configurations. These analyses indicate that a modified rougher-cleaner circuit incorporating a middlings recycle stream offers the best option for improving performance while maintaining a reasonable circulating load. In light of this finding, a full-scale test circuit was installed and evaluated at an existing preparation plant. Data obtained from the plant tests indicate that the new spiral circuit can simultaneously reduce the cut point and improve separation efficiency. Preliminary economic analysis show that the new circuit provides an attractive payback on capital investment.

Jan 1, 1999

Spirals have become one of the most popular methods for treating fine coal. Unfortunately, spirals tend to produce an undesirably high specific gravity cut-point and often misplace significant amounts of coal and/or rock. In the present study, a process-engineering tool known as linear circuit analysis was used to identify problems with traditional spiral circuits and to suggest alternative configurations. These analyses indicate that a modified rougher-cleaner circuit incorporating a middlings recycle stream offers the best option for improving performance while maintaining a reasonable circulating load. In light of this finding, a full-scale test circuit was installed and evaluated at an existing preparation plant. Data obtained from the plant tests indicate that the new spiral circuit can simultaneously reduce cut-point and improve separation efficiency. Preliminary economic analyses show that the new circuit provides an attractive payback on the capital investment.

Jan 1, 1998