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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

By I. M. Arbuthnot

Over the last five years, a large number of small to medium sized carbon-in-pulp gold treatment plants have been built in Australia, most designed to treat between 250,000 -1,500,000 tpa of ore. In many cases, the primary requirement was to get a plant built and operating in a short period of time and at minimal capital cost, relating to the limited capital resources and tight cash flow positions of these relatively small mining companies. Since the inclusion of both pre-leach and tailings thickeners resulted in an obvious and significant capital cost, most plants were built without thickeners, without doing a detailed cost-benefit analysis on their inclusion, However, the increasing use of High Rate Thickener?s (HRT s) in the mineral processing industries resulted in a reassessment, in some cases, because of their considerably lower cost. This reassessment was triggered primarily by the need to conserve water in arid mining areas, where borefields were costly to install and water was limited. It has become apparent, though, since startup and operation of these installations, that the savings in cyanide consumption is also a very significant factor and can be used as a primary justification for the installation of a HRT in many cases.

Jan 1, 1991

By Tristan Joubert, Fabio Panella, LiLing Chen, Yung Loo, Michael Devriendt, Nasir Qureshi, Ahmad Ali

Tunnel inspections have traditionally been carried out manually by inspectors writing up observations and taking photos of defects. The results from the inspection and the defects observed are dependent upon the rigor of the inspectors and may be subject to repeatability and consistency issues and is often time consuming with elevated health and safety risks. This paper will discuss work that is being carried out in developing and implementing an innovative hardware and software solution integrating machine learning to automate the process of capturing objective tunnel condition information, offering cost and programme savings as well as health and safety improvements

Jun 13, 2023

By B. Simser, T. Butler, A. Hall

The longterm future of Glencores’ mining operations in the Sudbury basin area of Ontario, Canada likely depends on mining deposits at depths below two kilometres. To gain a better insight into the rockmass response to mining, a geological scouthole program has been implemented at Glencores’ Nickel Rim Deep and Onaping Depth Project to gain insight into rockmass conditions ahead of the devel-opment face. The scouthole program involves drilling long (up to 600 m) subhorizontal boreholes drilled ahead of the development end and collecting data about the rockmass conditions from various geophysi-cal and mechanical tools (in addition to conventional core logging). Once all data has been collected and the borehole is available, seismic sensors are installed up to 450 m down the hole as part of the micro-seismic monitoring program with the leading sensor always located ahead of the development end. The recorded seismic data is used to provide realtime insight into the rockmass response to mining. On May 20, 2017 a flurry of seismicity with a maximum moment magnitude (Mw) of 0.7 occurred causing damage to the ramp heading. Data from the microseismic monitoring system had indicated that conditions at the development end were changing prior to the rockburst. A back analysis of the scouthole data indicated a clear anomaly in the rockmass at the location of the rockburst. The scouthole data also provided sufficient information to suggest that once this anomalous zone was exited, mining conditions would improve. With the microseismic monitoring system providing realtime information from the rockmass, the area was re-habilitated and ramp development continued successfully. Details of the rehabilitation and adjustments to the ramp development are discussed. Some correlations between the scouthole data and recorded micro-seismicity are also presented.

Apr 26, 2022

By W. B. Collingwood, D. Misra, T. Ghosh, S. Bandopadhyay

Understanding the variability of sulfur and calorific value in coal seams is critical to planning mining operations and marketing the mined coal. In this study, statistical and geostatistical techniques were used to explore the underlying spatial trends present in a large coal deposit. Eight prediction models for the sulfur content of the coal seam were developed. Six of the models were created using geostatistical techniques, while the remaining two models were created using other techniques. The performance of each model was examined by conducting cross validation exercises. The results of the study showed that very pronounced trends and anisotropies were present in the sample data, which had to be accounted for in the modeling. The study found that a cokriging model using sulfur and ash is the best prediction model for predicting sulfur content in this coal reserve.

Jan 1, 2014

By D. K. Sengupta

Increased recycling of waste paper has been emphasized in recent years in both the USA and Canada for environmental and economic reasons. Removal of ink particles from the waste paper pulp is therefore necessary. One of the most promising methods for ink removal is froth flotation. Our study investigated the feasibility of a simplified flotation scheme which showed that about 90-92% ink removal can be achieved while 95-97% ink removal is achievable if a hydrophobic polymer is used ahead of flotation. The clean paper pulp recovery was over 90%. The effects of pulping pH, flotation pH, and concentrations of flotation and polymeric reagents are discussed in the paper.

Jan 1, 1993

By Nicole R. Henderson

Many mining engineering graduates enter the mining industry lacking training in mine emergency management. As a result, mining universities in the United Sates and other countries are beginning to form volunteer student mine rescue teams to train mining engineering students in handling mine emergency situations and give them hands-on experience managing potential emergency scenarios underground. In the early 1980s, the Missouri University of Science and Technology developed the first collegiate mine rescue team in the United States. For approximately 30 years, it was the only successful collegiate team until the Colorado School of Mines (CSM) started its program in 2009. Currently, there are at least five collegiate teams in the United States and one in Canada. At the Freiberg University of Mining and Technology in Germany, the goal is to adapt the Colorado School of Mines Mine Rescue Program to develop a collegiate team of its own. Currently, mining engineering students cover the theoretical basics of mine rescue in an occupational health and safety lecture and take a basic, one-day mine rescue training course at the Central Mine Rescue Station in Leipzig. The course covers the basic mine rescue topics and gives students the opportunity to experience working in elevated heat and smoke conditions while wearing breathing apparatus. This training gives students a small insight into the importance of mine rescue and mine emergency management. Collegiate mine rescue teaches students the importance of mine rescue and mine safety by giving them hands-on learning experiences before entering the mining industry.

Feb 1, 2014

By Lowell T. Harmison

I appreciate very much the invitation to speak with you and the opportunity of bringing you messages from both the Secretary of the Department of Health and Human Services and the Assistant Secretary for Health/Acting Surgeon General of the U.S. Public Health Service. I would like to take this opportunity to congratulate you (the organizers of this Conference) on identifying the critical issues in the field and assembling such a broad array of experts to address them. I would like to present a brief view of the emerging framework for health that puts into perspective some of the aspirations of the Administration and to highlight several points with regard to prevention and occupational health. The goals are: 1. To improve the overall health status of our people. (This has been and will remain the National policy regarding health.); 2. To engage the Nation in the important effort of enhancing public health. (This is not reserved exclusively for the activity of the Federal Government or for State Governments. Public health has to be a cooperative effort that brings together all of the people engaged in the process of serving the people.); and 3. To pledge that health care will not be priced out of anyone's reach because of inflation. (It is clear that there are major tasks of bringing about economic recovery in our country. One aspect of this effort is to guard against the cost of health care not being allowed to rise beyond the reach of persons who need that care.) "How will these goals be achieved and what must change in the delivery of health and medical care in our society?" There are a number of real issues as well as perceptions that adversely affect the attainment of these goals: First, The cost of medical care is soaring and the public, industry unions and other elements of our society are becoming concerned. (They recognize the problem and are demanding a solution.); Second, There is a growing concern about the priorities that have been set. (For example, the evidence that preventive interventions are the most effective approach is overwhelming, yet medicine has not yet given that a high priority.); and Third, There is the perception that physicians do too much to too many people at too great a cost and that too much and too costly technologies are used. In view of the perceptions, we all must accept some changes and the challenges that needed changes will bring. A month before the new budget went to Congress, President Reagan went on nationwide television and told the American people that, "It is time to recognize that we have come to a turning point and we are threatened with an economic calamity of tremendous proportion and the [old business as usual treatment can't save us. Together we must chart a new course]." Now eight months down the road from this and a long Spring and Summer of discussion both within the Executive Branch and in the Congress, many plans and programs and concepts have emerged. The new course has been charted and the turning point has been made. Business as usual has been put aside and the Administration's leadership has been stretched and tested in putting forth a better approach with the reality that money is tight and that old habits of delivering care are difficult to change. The Congress has now given us a look at a new health budget that takes into account some of the harsh economic realities and that does make allowances for the persistence of familiar behavior. Against this background, it is now possible to begin addressing ways to provide health services to people at a price the Nation can afford to pay. There are without question difficult decisions involved but the Administration is committed to supporting and improving health care in America. It has been the President's contention that one of the principal causes of the inflationary spiral in the country was the steady and indefensible growth of the Federal budget. The problem stems from the fact that we have been living well, but beyond our means for nearly 30 years. Now we are discovering that there is a bottom to the barrel after all. It is possible for our society to run out of things like energy (oil), water or money. The health bills must be paid -- by Government, by insurance, by parents or by someone. Each year with a bigger shopping list and more money to spend the Federal Government went into the marketplace to buy. This action altered the

Jan 1, 1981

By Pascal Deschamps

"INTRODUCTION During the last decades, many underground facilities for the storage of hydrocarbons have been excavated worldwide and the technology is fully mature. Similarly to other underground structures, the initial basic design has to be adapted along with the work progress, in order to cope with the actual site conditions and in particular the geology, hydrogeology and associated rockmass quality. In addition, Client’s or underground Contractor’s constraints (such as resources availability, schedule or cost impact) may vary from design to construction and require last minute adjustments. Engineers are required to introduce flexibility and anticipation of unexpected situations (similar to the above-mentioned) while conceiving large underground facilities. Although most of the cases require only minor adaptations, crucial parts of the facility have sometimes to be considerably modified and reviewed. This article will present four cases evidencing how the design of one of these essential structures - the concrete plug – has been adjusted during site implementation without impairing the initial performances. Hydrodynamic containment The product containment of the unlined caverns discussed here is ensured by the principle of hydrodynamic containment. A permanent water flow is naturally or artificially maintained with an orientation toward the storage cavern and then, neither product-tight membrane nor lining are required. The hydraulic gradient (and the associated water flow lines), being directed from the surrounding mass toward the cavern, prevent from outward migration of the product. If the hydraulic gradient is not sufficient or if the water table is evidencing instability, water can be artificially injected into the rockmass through purpose-built boreholes, drilled from dedicated galleries. This water injection system, called the water curtain, is generally located several tens of meters above the level of the cavern. This principle is illustrated here after."

Jan 1, 2016

The mining industry has indeed gone global. International minerals producers are spending big money to move into countries that were off limits a few years ago. Due mostly to political reasons, these countries' huge mineral deposits - worth billions of dollars - were locked up and mining companies could only sit on the side and wonder "what if." Now much of the world is going the free market route. Once closed countries and developing nations are rewriting their mining and tax laws hoping to attract foreign investment to develop their natural resources. And big businesses - mining companies included - are lining up to get their share. But with new opportunities come new risks. While emerging nations are slowly accepting the free market concept and the privatization that goes along with it, many remain plagued with political instability and violence. Even developed nations carry their unique risks. Some of these include inadequate or contradictory legal and regulatory infrastructures, political patronage and outright corruption. So companies hoping to expand into new regions of the world must do more than examine the market. They must study the political stability and structure of a country, as well as its tax and environmental laws. And they must guarantee the safety of their employees. Control Risks Group is an international management consulting company that assists companies preparing to move into a new country. It employs about 225 people in 14 offices throughout the world. Control Risks personnel include lawyers, bankers and former law enforcement officers and intelligence people. The company held a one-day seminar in Washington, DC to update some of its clients on the state of affairs in various regions of the world. The seminar also covered extortion, corruption and product diversion. About 175 people attended the seminar. Speakers included Control Risks' operators, analysts and investigators. Here is a summary of what some of those people had to say.

Jan 1, 1998

By Nikhil Dhawan, SHAILA MIR

Consumer preference for ever-higher laptop performance coupled with laptops’ declining lifespans make them a significant contributor to electronic waste. An in-depth evaluation of elemental composition and distribution is important for determining metal recovery potential and sustainable recovery processes. In this work, the characterization of individual components of laptops is studied for the systematic identification of important elements and for streamlined and structured recycling, to reduce processing steps and improve economics. A process flowsheet highlighting various recycling routes by targeting metals and various components is also proposed.

By Luis Fernandez-Deza, James Hawn, Dustin Mount, Jean-Marc Wehrli

The RiverRenew Tunnel System project in Alexandria, VA forms part of a CSO scheme aimed at reducing overflows of combined stormwater and sewage into the Potomac River during storm events. A major piece of the project is a 12-foot internal diameter tunnel of approximately 12,000 feet length lined with a single-pass precast concrete segmental liner and excavated by an Earth-Pressure Balanced Shield TBM. The tunnel lies between 120 to 140 feet below grade in the clays of the Upper Potomac Formation with occasional dips of more granular, saturated soils of the Terrace Formation and the Alluvium. The TBM is launched from a figure-8 configuration Pumping/Screening Shaft located within AlexRenew’s operational Water Resource Recovery Facility. This paper discusses the challenges encountered during the launch of the TBM in short mode within a highly congested site and from narrow deep shafts.

Jun 13, 2023

By L. G. Wilson

In our comparison of California and Turkish colemanites, we should first place the discussion in context. In order to exclude technical considerations, which are not germane to this paper, we must make the manifest and basic observation that if colemanite were not acceptable for the production of glass products it would not be used, and we would not be interested in this comparison at all. Suffice it to say that the colemanites, being calcium borates, provide a necessary flux in glass manu¬facture, together with the requisite degree of physical strength and chemical durability which can be achieved only by the use in glass of a. flux substanti¬ally free from alkali; so the sodium borates are automatically excluded from the production of textile fibers. Thus we have today under consideration only California colemanite, Turkish cole mite, and, because it provides a degree of competition to both, ABA, or anhy¬drous boric acid, which, although it is a refined intermediate and of much higher cost, it is also of a much higher degree of purity, and its characteristics can easily be modified to produce a desired end product, so we must include it in any consideration of high quality borates. [Calcim Borate Pentahydrate] Colemanite is a [calcium pentahydrate,] with the formula Ca2B6011.5H20. It has a theoretical B203 content of 50.8%.

Jan 1, 1973

By Erich Sarapuu

Today's increasing needs for rapid excavation have stimulated efforts to break rocks without explosives. The application of electric energy for this purpose has been studied by a number of investigators. Following principles have been used in electrical rock breaking: 1. induction heating5 2. high frequency heating4, 14 3. microwave heating6 4. contact resistance heating9,12 5. resistance heating11,13 6. electron beam heating1, 3 7. plasma jet heating2, 8 8. arc heating7 9. condensor discharge energy14 In this paper the presentation of the principles of electrical fragmentation is limited to a process called "electrofracing". This technique uses electrical heating of rock by electrode contact resistance9 and resistance heating" phenomena. The electrically induced stresses inside of rock generate forces which break up the material. The fracturing of ore takes place by tensile stresses instead of compressive forces. The electric energy merely creates fractures in the rock and the separation of fractured material takes place by subsequent mechanical handling. Energy requirements in secondary breaking of iron ores have been about one to two kilowatt-hours per ton of ore. Power requirement is a function of the degree of fragmentation.

Jan 1, 1969

By Norbert Patzelt, Johann Knecht, Wolfgang Baum

High pressure roll grinding (HPGR) is a mature but still expanding comminution technology. In the metals mining industry, HPGR is slowly gaining acceptance as a cost-efficient, high-throughput alternative for plant optimization. The increasing need to treat ores with progressively lower grades, complex mineralogies, refractory metal occurrence and variable rock types requires an energy-efficient comminution technology that reduces metallurgical problems inherent in conventional crushing and grinding, while stabilizing leach and flotation circuits and increasing metals extraction. This paper will summarize our latest HPGR pilot test results for gold and copper projects in the United States and South America and their confirmation through the first HPGR operation in copper mining. This paper will also stress the use of the high pressure grinding roll as a metallurgical tool. The application of HPGR for the treatment of heap leach SX-EW ores, semi-refractory gold ores, waste rock material and concentrator feeds will be illustrated.

Jan 1, 1998

By Dale S. Preece

INTRODUCTION The Waste Isolation Pilot Plant (WIPP) is a research facility located in Southeastern New Mexico. The WIPP is being developed by the U. S. Department of Energy (DOE) to demonstrate the safe storage of defense-related radioactive wastes in bedded salt. Since the WIPP is a research facility. a number of large-scale in situ experiments have been planned and are currently under construction (Munson, 1983). These experiments were designed to study various aspects of nuclear waste storage in bedded salt such as mechanical responses and creep closures of drifts, thermal response due to heated canisters, and thermally-induced fluid migration. One purpose of the WIPP is to develop and demonstrate a general predictive structural analysis capability for a bedded salt repository. One set of experiments, called the Geomechanical Evaluation (Room G), is heavily instrumented to study the creep around several rooms with different configuration. A Layout of the Geomechanical Evaluation room is shown in Figure 1. One portion of it consists of wedge shaped pillar where two drifts intersect at an angle of 7.5 degrees. The pillar can be seen at the bottom of Figure 1. One purpose of the wedge pillar experiment is to study progressive pillar failure in the tip region. Another is to determine how nonuniform pillar thickness affects creep closure of the drifts. An important aspect of the experiments is the correlation between experimental data and corresponding pretest finite element analyses of the site. The finite element simulations serve two purposes. First, the computer simulations aid in understanding the experimental results by providing calculated stress. strain and displacement fields that cannot be measured directly. Second, comparison of calculated and measured drift closures serves as a method for validating or improving the finite element models and the constitutive models employed. The wedge pillar geometry required a 3-D finite element creep calculation. Results from these 3-D calculations will be presented in this paper. A 2-D plane strain double drift model which approximates the wedge pillar geometry at a slice perpendicular to the drift has also been performed and will be compared to the 3-D results in this paper. FINITE ELEMENT COMPUTER PROGRAMS Two finite element computer programs. JAC (Biffle, 1984) and JAC3D (Biffle. 1986), were used. JAC is a 2-D finite element program developed for quasi-static analysis of non-linear solids. It employs the conjugate gradient iterative technique to obtain a solution Spatial integration is performed using a single gauss point in each four node quadrilateral element. An hourglass viscosity technique is used to control the zero energy modes that occur with single point integration. The single point integration combined with the explicit nature of the program and exploitation of CRAY-1 computer architecture results in very efficient execution J4: results were compared to results obtained with eight other 2-D structural creep computer codes in the second WIPP benchmark exercise (Morgan, 1981) JAC3D was derived from JAC to treat 3-D finite element models and has many of the same characteristics including single point integration and hourglass viscosity. These characteristics have made 3-D creep analyses more reasonable by significantly reducing computation time The first exercise of the creep capability

Jan 1, 1986

By Tom Ireland, Sumi Eratne

The approach to Risk Management during the procurement of major projects often has a significant outcome on the ultimate successful delivery of a project. The $NZ4.4B Auckland City Rail Link project is the largest and most complex transportation project yet undertaken in New Zealand. Risk management prior and during procurement was undertaken in accordance the ITIG Code of Practice for Risk Management of Tunnel Works (TCoP) and through the use of an Alliance Geotechnical Baseline report. This paper describes the measures taken during the procurement process to achieve certainty with respect to outcomes and minimise project risks whilst also achieving value for money. This included the use of cloud-based delivery of geotechnical data and 3-D geological models, reducing tendering costs and allowing a focus on risk mitigation measures during the tender rather than data management.

Jun 13, 2021

By C Rutter, N Shea, K Kolobe

The Henderson mine, a panel cave mine in Colorado, has undergone multiple ventilation system changes to meet dynamic airflow needs. This paper explains the ventilation designs for different production panels, the challenges faced, and the modifications made to optimize the ventilation systems. The study highlights the importance of a robust ventilation system for safe and productive mining.

Mar 2, 2022

By Conrad W. Steller

What is the definition of a successful construction or development project? It could be described in many ways: a project that performs as designed; a project completed on time, a project completed within budget. The title of our talk today is, "The Advantages of Applying Design/Build -Construction Management to the Mining Industry." As our talk develops, you will see that rather than tell you how to apply this concept, we will discuss the advantages and details of Design/Build so that you can independently apply the concept. Design/Build is not new, and it cannot be universally applied. It has, however, within the past ten years, carved a specific and substantial place in the overall construction -development market. The reasons for its rather recent rise to considerable prominence as a concept is due, in part, to the increasing urgency of gaining productive access of a production facility and, in part, to the inherent advantages of the concept's economics--and they are considerable. If the Design/Build concept of contracting were fully understood, it would, without exception, be the favored way for private industry to contract for its new construction and development as well as renovation work. The basic advantages are: earliest possible access and completion at the lowest cost. Design/Build is often equated and compared to "fast track" or "turnkey" methods of construction. The Design/Build concept can, in fact, be both of these or neither. "Fast track", in and 6f itself, implies that the project will be phased construction, that is to say, it will be built quickly; whereas I "turnkey" is a measure of the completeness of the project, usually meaning essentially that the

Jan 1, 1977

By Richard O. Rouse

Today, I want to challenge this audience by charging each of you to be a greater manager and superior engineer to manage and engineer our way through the 1980's and profitably overcome all the present and proposed government regulations. May of the present and proposed regulations will tax you and your company's management and engineering to the brink of physical and monetary exhaustion, but I believe we can succeed and coal can be America's answer to her hungry energy needs. To put our 1980's challenge into perspective, I want to give two great challenges we must overcome. First - We must improve on our process of compliance to new government regulations in the technical and equipment end of our industry. The Lord said, "Let There Be Light". MSHA said, "Let there be light in underground coal mines". Since that time, we have lived through an unmanageable and tremendously costly period of compliance.

Jan 1, 1980