Search Documents

By K Timtner

As shown in former publications there are problems in load sharing of backstops in multiple drives of conveyors. Therefore, detailed calculation methods and design recommendations are required. In this paper various designs of load sharing methods are described and a dynamic torque calculation method will be presented. With this method the loadsharing properties for low and high speed backstops are calculated and compared. These properties depend on the spring characteristic of the drive train between backstop and load. Furthermore, the properties depend on the method of torquearm support and shock absorber configuration. Remarkable differences for external and internal backstops are shown

Jan 1, 1998

By W. Robert Power

Dimension stone includes a wide variety of natural materials that are put to an equally wide variety of uses. It is possible to classify dimension stone according to the end use to which the stone is put or according to the lithology of the stone. Both schemes are used by the United States Bureau of Mines in the annual Minerals Yearbook. The 1969 Yearbook lists 15 specific uses and has additional miscellaneous catagories. The same Yearbook lists five specific rock types or lithologies, and also includes a miscellaneous category. In a short presentation it would hardly be possible to list and define all these categories, much less discuss the evaluation of deposits with regard to all possible combinations. Besides, I am only slightly familiar with some of the uses and their requirements. I have therefore chosen to limit my remarks to some special problems in evaluating dimension stone that is to be cut and finished to specific sizes, tolerances, and finishes for use in buildings and some monuments. This use class is called cut stone in the Minerals Yearbook. In terms of dollar value it is the largest single use category. In 1969 the dollar value of cut stone was $29,122,000 which is more than twice the value of the next largest category. For those of you who are interested in other use applications of dimension stone I suggest that you start with recent articles by Bowles (1960), Currier (1960), and Barton (1968).

Jan 1, 1972

By H. B. Weaver

The development of a method to manufacture diamonds has been rated as one of the out- standing scientific achievements of our time. The story is both interesting and significant. This paper will quickly review history of diamond and manufactured diamond. Next, it will discuss manufactured diamond as a product -- how good is it -- and what is the significance of this scientific achievement. And finally, present a few thoughts about the future of this technology and this product. For centuries, diamond was found only in alluvial deposits, primarily in the Golconda fields of India. As a result, man knew nothing of the process by which the stones were formed. In 1860, diamonds were found in South Africa under completely different conditions. Here, for the first time, they were found in volcanic pipe -- their mother ground. These volcanic pipes are roughly cylindrical columns of rock which go deep within the earth. The theory as to the formation of diamond was presented by the geologists in that era. The theory states that molten rock was thrust up through a layer of carbonaceous shale where it picked up the carbon necessary for diamond formation. It was generally agreed that diamond was formed approximately 240 miles below the surface of the earth, thus indicating that extremely high temperatures and pressures were involved.

Jan 1, 1964

By Peter N. Loncar

Most miners dream of finding a gold mine sometime during their mining careers, but not very often do such dreams come true. On the tenth day of September, 1962, our dream of finding gold came true when the results of the third drill hole were received. This was undoubtedly one of the most exciting days of our lives. Little did we realize then that this was the beginning of a major discovery destined to became one of the largest gold mines in the country. Discovering and mining gold is not entirely new, however, to Eureka. County a old Lynn Mining District in northeastern Nevada. Since 1900 there has been sporadic activity, mostly consisting of small lode mines and placers. These have produced totally about $300,000; and existence of our orebody would probably have remained unknown had it not been for the United States Geological Survey. The USGS extensively mapped the Roberts Mountain Thrust and published a paper indicating that mineral occurred along this fault and in some places was gold bearing. Utilizing this information, our Newmont Exploration geologists located an area in which: drills were brought in to test their theories. By keeping flexible in our thinning and working, we were able to bring a raw prospect to a producing mine with ore reserves of eleven million tons in a short three-year period.

Jan 1, 1965

By M. G. Vieira

This investigation addressed the possibility of producing pellet feed at a silica content of = 1.0% using a representative sample of Samarco´s mechanical flotation tailings. This sample contained 11.0% Fe and presented an F80 = 116 µm and a d50 = 63 µm. The higher silica content was verified in the coarser fractions and the higher iron content in the fraction -37 µm. Specular hematite is the most abundant mineralogical phase in the fraction -37 µm. The technological tests used one of four methods: magnetic concentration using a wet high-intensity magnetic separator, magnetic concentration using a SLon high-gradient magnetic separator, reverse flotation or direct flotation. The methods using the magnetic concentrator SLon, reverse flotation and direct flotation did not present results meeting the target of the study: iron content in the concentrate (rougher stage) greater than 34% or iron recovery greater than 80%. Cleaner stages were not achievable with the resulting concentrates. In contrast, the most successful method consisted of using wet high-intensity magnetic separators (WHIMS) as a rougher stage and reverse flotation as a cleaner stage. Using this route, it was possible to produce a pellet feed with a silica grade of 1.0% and high specular hematite content.

Jan 1, 2010

By Guy T. McBride

Mr. Chairman, Fellow Keynoters, Ladies, and Gentlemen: It is purposed to consider the theme of this meeting, "The 1970's - Pivotal Decade for the Mineral Industries," from the particular -- some would say peculiar -- point of view of one engaged in mineral engineering education, and this coign of vantage prompts the textbookish subtitle, "Problems and Solutions (?) in Undergraduate Mineral Engineering Education." Three interrelated problems, or problem areas, will be presented and discussed, and where solutions seem to be emerging or seem worthy to be suggested, they will be identified. The three problems are: 1. The goals, and therefore the course requirements, of the undergraduate curricula are in question, 2. The unit costs of undergraduate education appear excessive to those who bear the charges, and 3. The social ambience of the day affects for the worse the work attitudes and the career motivation of both prospective and in-course students. The Need. - Any discussion of these problems must bottom upon recognized national needs for minerals and a technologically sound minerals industry staffed by competent engineers, particularly at the exploration, development, and production levels, Fortunately, these needs have been recognized and to some extent quantified, and they are even now under further intensive study by some of the most competent members of our society and profession. The latter reference is, of course, to the current work of the National Commission on Materials Policy (U.S.A.) under the executive directorship of Dr. James Boyd. Predating this, and perhaps to some extent

Jan 1, 1972

By Kefton H. Teague

An article entitled "The Rule of the Geologist in the Industrial Mineral Field" by G. R. Gullet, was published in the August, 1967, issue of the Canadian Mining Journal. Mr. Gullet defined industrial minerals as follows: "Industrial minerals are largely non-metallic minerals and rocks that find value because of their physical or chemical properties." This definition is brief, but all-inclusive. Mr. Gullet continues, "They include all useful minerals and mineral commodities except those used as fuels and those from which metals are extracted. Factors in the evaluation of an industrial mineral deposit are generally as different from those used in the evaluation of a metal deposit as is the assessment of a potential oil field. The key to the successful development of an industrial mineral, deposit is more often a balance of accessibility, transport, and proximity to markets than to any natural quality advantage of the deposit itself."

Jan 1, 1972

By B. Andersen

An accurate knowledge of Interactions among mineral particles and between such particles and dissolved and precipitated species Is Important in developing efficient separation processes. In this investigation interactions in Florida phosphatic clay waste, that are relevant to dispersion and selective reagent adsorption, the two main prerequisites for selective flocculation, were studied. Initial studies with artificial slimes, consisting of pure clay and phosphate minerals, showed dispersion of artificial slimes to be relatively easy. The problems that were encountered during selective flocculation of the artificial slime were due to unselective polyacryllc acid adsorption on clay, which was caused by the presence of multivalent calcium ions on the exchangeable cation positions on the clay surfaces. This problem could be solved by exchanging calcium for sodium, which reduces the interaction between the polymer and the clay surface. This procedure, however, was not successful for mineral mixtures. Natural slimes were found to be much more difficult to disperse. This was attributed to the presence of cementing materials such as humic substances and Ai and Fe (hydr)oxide precipitates. Selective removal of these cementing materials resulted in good dispersion and partial separation. Further increase in separation of natural slime is likely determined by the presence of calcium on the clay surfaces, as was found for the artificial mixtures.

Jan 1, 1992

By Scott Ellenbecker

Mining has evolved in recent years, taking steps forward in the way that the industry is considerate of the environment and the communities in which it operates. Technology plays a major role in that evolution. Osisko Mining?s Osisko Mine near Malartic, Quebec is developing a new way of doing business. One manager said, ?We are building the Osisko culture,? but the company is doing many things that could become industry changers. Much of the change is driven by mine ownership and management to offer a better workplace and better community relations. Mining equipment manufacturers are changing, too, by engineering products with more operator comfort, fuel economy, ease of maintenance and more cleanly designed machines. And for those drills working close to communities, smaller bore sizes and sound retention are just two changes for the better.

Jan 1, 2012

Maximizing margins in competitive markets demands superior productivity. Unfortunately, management systems developed early this century for other industries often drive counterproductive behaviors choking mining productivity. Many executives and managers waste valuable time and effort relying on simply training and communicating to improve managerial practices and attitudes. In covering practical human behaviour, the paper explains why this fails -and explains how to use systems to successfully drive improved managerial practices and attitudes. It highlights use of modern performance Measurement, Analysis and Reporting systems to drive behaviors and improve margins -without capital investment -and make executive and managerial work easier and more effective.

Jan 1, 1999

By J. Castaneda, J. Schmidt

"INTRODUCTION Chino is an open-pit copper mining complex faced with intricate material routing requirements. Historically, this was challenging at the mine, in part because the shovel dig plan, haul plan, and dump plan were prepared completely separately. The mine now uses an integrated workflow for faster evaluation of schedules, which facilitates preparing balanced cutoff grade-to-equipment requirements, supports better mineral production, and improves schedule viability, while considering operational implications. Located in the state of New Mexico, Chino is one of nine Freeport-McMoRan mining operations in North America. This presentation discusses the benefits of implementing an integrated approach to tactical mine planning, and shares practical examples that were learned as Chino implemented an integrated tactical planning method. This includes improvements in completion time for preparing a schedule, minimal risk from manipulating Excel macros, data integration required to make short-term planning decisions, and better understanding of the mine plan’s effect in relation to the business’s key performance indicators. Ultimately, the integrated approach to tactical mine planning at Chino has led to production forecasts which are more achievable and reduced planning and execution variance. PROJECT OVERVIEW Chino mine is a porphyry copper deposit wholly owned by Freeport-McMoRan, the largest publicly traded copper producer in the world. Chino mine is located in Grant County, New Mexico, a short distance east of Silver City. Ore material mined from the pit today includes oxides, primary sulfides, and secondary sulfides. The mineralized material is sent to a mill, with a rated throughput of 42,000 tons per day, or to ROM leach pads with variable dumping capacities. At Chino, the short-range objective is to maximize total copper pounds sent to the mill, but no fixed cutoff grade accomplishes this for all periods. Instead, 12 different material classifications, including four sulfide classes that can feed either the mill or other destinations, and 38 cutoff bins, are aligned with the needs from operations, leaching, and the concentrator to create a schedule. Cutoffs vary from one week to another to cope with a highly intermittent ore body."

Jan 1, 2018

By David Kress

Grinding mills, both autogenous and ball can be powered by several basic means. The three methods used today are girth gear drives, gearless drives and trunnion coupled reducers. This paper will focus on the first of these methods -girth gear drives. The girth gear drive has been used on thousands of mills which continue to operate successfully. These drives are noted for their simplicity and low cost. In the past, the horsepower capacity of girth gears has been slow to keep up with the horsepower increase required by the mill builders, particularly since the advent of the SAG mill. Gear manufacturers had capacity for 2000 HP mills in the 1950's, 5000 HP in the 1960's and 6500 horsepower in the 1970's. The 70's and 80's brought dual pinion girth gear drives which allowed mill sizes beyond 10,000 horsepower. Gear manufactures who could not keep up with the pace of the horsepower demands and the quality and reliability demanded by the mill builders and users have fallen by the wayside.

Jan 1, 1991

By R. Fernando

"The National Institute for Occupational Safety and Health (NIOSH) National Personal Protective Technology Laboratory (NPPTL) is leading an effort to develop the next generation of self-escape breathing apparatus for egress from confined spaces in emergency scenarios. A backpack style closed-circuit mine escape respirator design was one configuration explored as part of the research imperative directed by the 2006 MINER Act. Stakeholder feedback from MSHA and at the NIOSH Breathing Air Supply Partnership Meeting indicated a smaller belt worn unit that does not sacrifice performance is desirable. This paper outlines some further technology advancements that may be investigated toward developing such a small-sized respirator. Technologies being considered are novel chemicals for improved carbon dioxide (CO2) absorption and oxygen (O2) production, eliminating a dedicated CO2 scrubber by incorporating its function in the spaces of the respirator’s breathing loop and storing O2 in a liquid form with long standby capabilities. When these technologies are applied to a future design, there is the possibility of having an escape respirator that can be belt worn and capable of being certified to 42 Code of Federal Regulations (CFR) Part 84 standards, including sub-part O for escape purposes including mine escape. BACKGROUND NIOSH NPPTL has a Research and Development effort to provide mine workers with state-of-the-art breathing air technologies to comprehensively support initial and continued self-escape, refuge alternatives, and rescue needs, resulting from mine emergencies. As part of this R&D effort, NIOSH invested in the development of a next-generation closed-circuit mine escape respirator (CCMER) which would be compliant with NIOSH’s respirator standard requirements, 42 Code of Federal Regulations Part 84, including sub-part O. The design features of the CCMER also address the MINER Act’s requirements for transitioning between devices without the need for doffing the initially donned device. It would also allow for improved protection when using voice communications with a donned device ."

Jan 1, 2018

Ventilation 'is currently used in mines to sustain human life, prevent explosions, and provide a more healthful work place. Future automated-mining systems could use ventilation techniques quite. different from today's practices. The Bureau of Mines is anticipating various methodologies for ventilating the automated mining systems which are now beginning to emerge in the mining industry. This paper examines the special ventilation requirements for automated mining systems. Topics include requirements for automated systems, current studies with blowup ventilation tubing, and ventilation of two types of highwall -ripper type mining machines.

Jan 1, 1990

By Francis Martino

Just as coal producing mines are faced with various handicaps which control the quantity of coal produced and sold, the subsequent user of that product is faced with parameters that impact the optimum utilization of coal. Traditionally, the industry focused on the quantity of mineable coal in a reserve. The mine planning development was primarily concerned with two important criteria: (1) safety and (2) the productive efficiency in a quest to produce the lowest cost coal.

Jan 1, 1982

The past decade has seen remarkable progress by the railroads both in equipment and concepts in the handling of dry bulk. materials. While such shipments have always been an important part of the traffic handled by the railroads I little was done to improve the efficiency of handling or toward attempted optimization of equipment design before 1960. Several developments at about that time turned attention to this important segment of railroad traffic. One was the construction of a successful coal slurry pipe-line. Another was the promise of substantial economy in electric power transmission by ultrahigh voltage systems and finally, came the growing technological and economic feasibility of nuclear fuel electric generating plants. Each of these developments was a threat to the coal traffic of the railroads --the most important single commodity they handled in terms of revenue and tonnage. By the mid-1950's I Southern Railway management had become most concerned with its growing investment in freight car equipment and the declining revenue productivity of the capital employed. Additionally I there was substantial concern with the loss of business and potential losses in the area of the railroad's greatest economic advantage --bulk commodity movements. In 1958 a small team was established to study this problem. They arrived at two conclusions. The first conclusion was that within limits of maximum gross allowable weight on rail the lowest unit net capacity cost of investment came at maximum allowable gross weight per car unit. The second conclusion was that with a high degree of utilization costs per weight unit transported could be reduced to the pOint where

Jan 1, 1971

By K. R. Griffin

New and developing communication systems enable underground miners to not only connect to the surface from an increased communication coverage area but also to be discovered in the event of an emergency. Communication and tracking systems are required by MSHA regulations, aiming to enhance health and safety and routine production in underground operations. Modeling a mine?s potential communication coverage area will increase overall coverage and efficiency of the communication network itself. Modeling the propagation of wireless communications enables ideal broadcast locations to be found when designing a communications network. Strategic placement of broadcast devices results in a reliable communication network that can better withstand disruption in both daily operation and emergencies. This paper will discuss recent regulatory developments in underground coal communication systems, the implementation of these new technologies, and how communication system?s networks can be modeled and analyzed using computer simulations.

Jan 1, 2010

By V. A. Temeng, M. Owusu-Tweneboah, K. Awuah-Offei

The mining industry has long recognized the value of dispatch systems in open pit mines as they reduce load and haul costs. Over the years, researchers have proposed many dispatch systems with various limitations and advantages. The simplest dispatch algorithms are the so called 1-truck-for-N-shovels dispatch strategy. These algorithms are limited by the fact that their objective functions do not consider all the objectives of a mine and cannot be applied to all possible truck-shovel configurations. They are also myopic in nature. However, they are simple and computationally efficient and do not require occasional updates of the upper stage problem as required in multi-stage dispatch algorithms. In this work, an agent-based truck dispatch algorithm that conceptualizes trucks as intelligent agents that make autonomous dispatching decisions to maximize their utility is proposed. The advantages of this algorithm includes utility functions that encapsulate all of management’s objectives and agent’s with broad situational awareness. They are also more suitable for autonomous trucks. We evaluate the new algorithm against a simple 1-truck-for-N-shovels dispatch strategies using discrete event simulation. The simulation results show that the new utility function has significant advantages over 1-truck-for-N-shovels inspired utility functions. Future work will incorporate adaptive behavior into the model via reinforcement learning algorithm. INTRODUCTION In an attempt to optimize truck shovel operations in open pit mines in order to reduce the cost of haulage operation, which according to (Alarie and Gamache, 2002) is estimated to be about 50-60% of the total cost of mining, several effective and efficient strategies have been developed. Optimizing truck haulage systems in an open pit mine is one of the greatest challenges of mining engineering and has been the subject of many research projects. It is important that haulage systems are designed to be efficient, in order to minimise haulage cost, improve profitability and increase the total mine value. Although optimizing the number of trucks required in the operation of open pit mines can help reduce the cost, an effective and efficient truck dispatching system add value by ensuring that the available trucks are used efficiently. With truck dispatching systems, the trucks are normally dispatched between the crusher and dumping station (e.g. waste dumps and stockpiles), and the shovels in order to maximize the total output, obtain grades targets, reduce fuel consumptions and other objectives. Truck dispatching, which can have one or more objectives, is typically subjected to certain operational constraints such as truck and shovel capacities, empty and loaded trucks speed, among others. The problems associated with truck dispatching was first mentioned by Dantzig and Ramser (1959) after they made an attempt to determine the optimum routes of a fleet of delivery trucks between bulk terminals and a service stations. The problem occurs in several industrial systems besides mining (Alarie and Gamache, 2002; Gendreau et al., 2006; Rego and Roucariol, 1995). The dispatching problem, also referred in literature as the vehicle routing problem, has seen a number of modifications and extensions with Bertsimas and Ryzin (1991) presenting a dynamic and stochastic vehicle routing problem, and Ralphs et al. (2003) also adding to the original concept, the concept of vehicle capacity routing.

Jan 1, 2019

By K. T. Valsaraj

The separation process called solvent sublation for the removal of two hydrophobic compounds (penta-and tri-chlorophenols) from the aqueous phase is discussed. A steady state mathematical model for the process is discussed. The process was conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1992

By R. H. Church

The Bureau of Mines' Tuscaloosa Research Center has developed a field test unit (FTU) which dewaters mine and/or mineral processing by-product slurries. The feed material (by-product slurry) is mixed with a known quantity and specific type of synthetic polymer (usually a polyacrylamide) to induce flocculation in a continuous operation. The flocculated material passes over a specific number and size of slotted stationary screens which separates the flocculated solid material from the "clean" water. The "static screens" are positioned at a fixed angle to maximize flow capacity and capture of the solids content. An investigation was conducted at an industrial crushed stone operation located near Birmingham, AL, to determine if the Bureau's FTU could successfully dewater the waste slurry generated during grinding and sizing operations at this facility. The investigation showed that waste slurries could be dewatered to 50 pct solids, at a polymer cost of approximately $0.85/ton of dry solids treated, and resulted in approximately 85 to 95 pct solids recovery. The dewatered material continued to consolidate and reached 69 pct solids in 24 h. Presently, the waste slurry generated at this facility is discarded into impoundments. However, this research has identified the recovered waste as an economically marketable product.

Jan 1, 1994