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By Oswaldo Ortiz Sánchez

El presente trabajo describe la alternativa de uso del mortero de resina en la fijación de pernos de anclaje de las excavaciones mineras, consolidación y disipación de vibraciones en los cimientos de plataformas para la instalación de molinos, winches, tolvas, etc. Esta opción surge en respuesta al problema de reforzamiento con pernos de anclaje en ambientes con aguas corrosivas o en proceso de deformación acelerada en las excavaciones mineras, así como ante obstáculos de subsidencia de cimentación en plataformas, donde se encuentran instalados equipos de gran tonelaje, y que producen fuertes vibraciones durante su funcionamiento.

Jul 31, 2003

By Adam Powell, Matthew Earlam

INFINIUM, Inc. is scaling up a new molten salt electrolysis process for producing rare earth metals. Instead of conventional carbon anodes, this process uses Pure Oxygen Anodes™ which employ a stabilized zirconia solid electrolyte between the molten salt and anode. This eliminates two problems with today's rare earth metal production technology. First, it eliminates carbon anodes and contamination of the product by carbon and its impurities, enabling 10-100 times larger batch size than current practice, and lower labor costs. Second, it eliminates emissions of perfluorocarbons (PFC) such as CF4 and C2F6, which are very problematic greenhouse gases with 6000+ times the global warming potential of CO2. The zirconia also enables a sealed vessel with no LiF emissions, creates a reducing environment enabling use of low-cost welded steel vessels, and either produces a high-purity oxygen by-product or can use natural gas to reduce the necessary electrical energy with no HF production. This paper will describe the technology and its current status for rare earth metal production.

Jan 1, 2014

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 years, until in 1936 probably more than 80,000 such units were put into use, According to reports of the Bureau of the Census 75,543 residential stokers mere sold in the first 10 months of 1937 by 108 manufacturers. This rapid expansion has made itself felt in the coal-mining, industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912 in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of tie present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By Brendan Demich, Joseph McGuire, Emily J. Haas

Near misses recorded and reported by workers can provide awarenessto the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, it is unclear what the value of these reports are, if any, and how they influence subsequent actions or controls to reduce on-the-job risks. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. Of those, 167 were valid near misses that occurred at work. Researchers coded the reports using a qualitative 5 × 5 risk matrix. Of the 167 near misses, 19% were deemed low risk, 25% moderate risk, 30% high risk, and 26% critical risk. Several patterns in the near-miss incidents were documented, including classification of incidents and common corrective actions referenced (i.e., elimination/substitution, engineering control or redesign, work process/procedures, and personal protective equipment). The analysis provides insight into ways that risk communication and management programs can be improved to reengage workers and their situational awareness on the job.

By L. R. Plitt, A. A. Turak, B. C. Flintoff

"Since the publication of empirical cyclone models by Lynch and Rao in 1975 and by Plitt in 1976, the technical literature on this subject has consisted primarily of reports of applications, with only a few articles discussing basic modifications or enhancements in model form. In fact, most of the modelling eff ort in this period has been concerned with theoretical models based on the hydrodynamics of multiphase flow. (Preliminary resutls have been encouraging, however, it will be some time before this approach reaches the practical application stage.) This paper presents a review of empirical cyclone modelling technology, with an emphasis on developments since the mid 1970s. The topics addressed include homogeneous and heterogeneous ores, parameter estimation techniques, parameter confidence intervals, and the introduction of a new conceptual model of cyclone operation.IntroductionSince their first reported application in the mineral industry by Driessen (1939), cyclones have become a common unit operation in all of the process industries. The widespread use of the cyclone stems from its relative low cost and its versatility. It can be employed to carry out liquid-liquid, solid-liquid and solid-solid separations. It is the area of solid-solid separation which is of greatest interest to a mineral processing engineer. Historically, this area was divided into two application categories: (I) Separation according to density, the cyclone washer, and, (2) Classification according to particle size, the cyclone ciassifier. (When water is the carrier fluid, the cyclone is more often called the hydrocyclone. For the purposes of this paper the two names are used interchangeably). Classification is the principal application in mineral processing circuit s. Within this category, the cyclone is most commonly employed to provide some positive control over the size distribution of product from a grinding circuit. Other uses include sand-slime separation prior to froth flotation and mill tailings treatment, either for dam construction or in backfill preparation."

Jan 1, 1987

By H. Tudeshki, A. Tayebi

"The large extent of global production and consumption of aggregates from quarries, grabs one´s attention and makes its substantial and essential standpoint in the world today pretty clear. A great amount of aggregates is utilized in civil engineering applications such as road construction, railway industry, concrete production, etc. Considering this fact that igneous rocks display a higher strength and abrasion resistance, this type of rock is preferred in the field of civil engineering. For all these applications, rock quality assurance is a key factor and certainly unavoidable, and it has great influence on the quality of constructions in civil engineering. One of the major problems encountered by both the producers and users of igneous rock is the fact that, with the passage of time, some specific rocks lose their strength, up to a complete loss of structure or in other words, their disintegration and degradation. In the last decades, different methods and procedures such as Glycol test, methylene blue dye test, as well as the Los Angeles test have been introduced to distinguish these rock properties, and to identify these problems. However, as these methods are time consuming, hard to perform, only to be applied to hand-piece samples, requiring special laboratory equipments, and only possible to be accomplished under laboratory conditions, their application has always been limited to some specific cases, and they are neither recommendable nor advantageous. In addition, these methods provide partially different results for the same rock. To address this widespread quality management problem of the quarry industry, a relatively quick, easy and user-friendly approach is necessary. It calls for a systematic solution with a device that can simply be used day to day in a mine for quality control of the quarry´s daily production. This scientific research is concentrated on developing a systematic method for early recognition and diagnosis of rock quality, in order to control and manage the quality of the quarry production in advance. This method was developed, based on the procedure of the magnetic susceptibility measurement. The obtained values can lead to valuable information regarding the quality of the rock and allows the quality control process to be accomplished and performed at the borehole location. This approach has been assessed through extensive field and laboratory studies. A detailed and comprehensive discussion will be made on the results of the experiments. The advantages and impacts of the application of this method, on increasing the reserves and environmental protection are also discussed."

Jan 1, 2011

By F. S. A. de Frey

The main users of computerised financial evaluation tools in the mining industry are the mining investment analyst, the mine manager together with his financial manager and the mining student (undergruadate and post-graduate). The mining investment analyst's needs mainly centre around the-micro and macro aspects affecting the mining industry in general. The mine manager needs a tool to assist him with the planning, reporting and controlling of production, costs, efficiency, productivity and cashflow. For the mining student studying Financial Evaluation, the main need is for a computer program which will assist him in learning the basics of the subject. This paper concentrates on the needs and objectives of the course Financial Mine Evaluation, the approach to which is presented. Emphasis is placed on the practical computing sessions and the role of the FCS-EPS package as a training tool.

Jan 1, 1987

By A. W. Bester

Paper written on project work carried out in partial fulfilment of B. Eng. (Mining Eng.) Cullinan Diamond Mine currently handles 3.2 million tons of run of ore per annum. This is done by means of an underground train system, which is located at 763 metre level. Four trains, one in each quarter of the pipe, collect ore from passes and transport it to centrally located tips in the north and south of the pipe. The ore is then split into coarse and fine fractions. The coarse fraction proceeds to the primary crushers in the north and south. Historically, mining has been performed in such a manner that an equal amount of ore has reported to each quarter of the pipe. However, the tonnage profile of the mine will change such that the ore will no longer be split equally. For approximately five years the majority of ore will report to the east and thereafter most of the ore will report to the western portion of the mine. This will continue for the remainder of the current infrastructure level?s operational life. Coupled with this is the fact that the mine is aiming to increase its annual production to 3.8 million tons. The result is that the current ground handling system cannot accommodate the additional tons and therefore alternative ground handling options have been investigated. The continued existence of Cullinan Diamond Mine relies on finding a system that can economically handle the additional tonnage. Three options were investigated. Firstly, a train option, which would be an upgrade of the current system, was investigated. Two truck options were also investigated, the first of which was a conventional truck option. The second truck option was more interesting and involved an unfamiliar Combi truck system. The truck options were investigated primarily due to the fact that the block height of the BA West (a new production block) can be increased by 15 meters if a truck option is decided upon. This would create a significant increase in revenue for the BA West project. Each of the options was assessed in terms of its physical and financial feasibility. In terms of the physical constraints, it was found that all three systems could work. Detailed financial analysis indicated that either of the two truck options would be a suitable solution. However, due to the limited information regarding the Combi truck option, it should be further investigated. This applies particularly to the actual running and maintenance costs for the equipment.

Jan 1, 2005

? The economic health and national security of the U.S. depends on the continued availability of, and access to, reliable and affordable energy and mineral resources. However, America is hindered by a costly, inefficient and often redundant regulatory structure that thwarts domestic investment, expansion and job creation. The annual cost of federal regulations in the U.S. increased to more than $1.75 trillion in 2008; averaging $8000 per employee.(The Impact of Regulatory Costs on Small Finns, SBA, 2010) ? The complexity, uncertainty and delays within the current permitting system places the U.S. at a competitive disadvantage with many other countries that have both abundant mineral resources and a more welcoming business and regulatory climate. As a result, American and international mining companies often move overseas or across borders to invest capital, create local employment, and produce the critical minerals America must then import at higher cost, while sacrificing employment and economic stimulus. ? According to Behre Dolbear, the U.S. is ranked lowest globally due to the lengthy permitting period required before mine development can commence. (Where not to Invest, 2010).

Jan 1, 2011

By Michel Ruel

"This paper describes how to make advanced control choices when difficult processes need improvement. The decision-making process involves choosing between a rules-based approach and a model-based approach as well as weighing benefits and drawbacks, complexity and simplicity, investment and results. This paper will present briefly each solution: basic control, advanced regulatory control, model predictive control, and expert systems such as fuzzy logic controllers and neural networks. The article then proposes a decision tree for selecting the most appropriate approach. A table will compare usage, development, commissioning, maintenance and lifecycle costs for each approach. Finally, conclusions and suggestions will summarize the methodology.INTRODUCTION Advanced process control (APC) is a popular topic. How can one decide whether advanced control should be added to an existing system? Advanced control is used to improve performance, stabilize production, handle constraints, protect equipment and manage grade changes. Most plants use feedback controllers, usually PID (proportional, integral, derivative) controllers. It is common to develop special control schemes to handle more complex processes. In classic PID process control, a controller brings a single value close to a set point using a single manipulated variable. On the other hand, APC brings several values close to optimal targets simultaneously using several manipulated variables. APC's four main strategies are advanced regulatory control, model predictive control (MPC), fuzzy logic and neural networks. Simple solutions are always preferred. Complexity will be increased if performances (production, quality, etc.) are below par. Profitability analyses should be conducted to validate project viability. Needs—not trends—should dictate choices! Before increasing complexity, it is important to define needs, goals, technical support, budget, etc. All these approaches entail strengths and weaknesses. Building a project based on technology rather than needs spells trouble."

Jan 1, 2014

By Henry Kreisinger, John Blizard, B. J. CROSS, C. E. Augustine

This report gives the results of 26 tests of a four-pass Edgemoor boiler fired with powdered coal at the Lakeside station of the Milwaukee Electric Railway & Light Co. The tests were made by the fuel section of the Bureau of Mines in cooperation with the research department of the Combustion Engineering Corporation and the operating department of the Milwaukee Electric Railway & Light Co. The object of the tests was to determine the thermal efficiencies and capacities obtainable by burning powdered coal under large central-station boilers, and the possibility of operating such boilers continuously at high efficiency and capacity without destructive effect on the furnaces and without difficulties in refuse removal. In any system for burning pulverized coal the furnace is the most important part because, to justify the cost of pulverizing, the powdered coal must be burned with higher efficiency than coal fired with mechanical stokers. In other words, it is the furnace that by giving higher thermal efficiency must pay for the installation, maintenance, and operation of the pulverizing equipment. No matter how simple the apparatus for the preparation of pulverized coal may be, or how simple the pulverizing process, unless the furnace is so designed that it can be operated continuously with high thermal efficiency, the whole system is a failure. For high thermal efficiency the coal must be burned almost completely with low excess air. But low excess air and complete combustion give high furnace temperature, which in turn causes erosion of the furnace lining and fusion of the ash; and removal of the fused ash is difficult. The necessity of complete combustion with low excess air thus brings with it these two important problems in the design of a furnace for burning powdered coal: 1, Prevention of erosion of the furnace lining; 2, easy removal of refuse from the furnace. For the purpose of solving these problems, the boiler tested was equipped with a furnace having hollow walls, through which about 60 per cent of the air needed for combustion passed before it entered the furnace. By passing through the hollow walls, the air cooled the furnace lining and prevented excessive erosion. A water screen was placed in the furnace about 3 feet above the bottom to keep the refuse deposited at the bottom from fusing and to make its removal easy. The design of the furnace, water screen, and burners was based on the experience gained in the previous cooperative tests1 with a smaller furnace, experimental water screen, and burners at the Oneida Street station of the Milwaukee Electric Railway & Light Co. The boiler tested had 13,057 square feet of heating surface. It was one of eight boilers fired with powdered coal, and was designated as boiler No. 8. The Lakeside station is the largest central station in the world that burns powdered coal exclusively. The coal used in the first five tests came from Illinois. The fuel in the other tests -:vas a mixture of Illinois and Pittsburgh coals.

Jan 1, 1925

Approximation of Surface Area of Fines in Blast Induced Fragmentation The surface area of fragmentation, especially in the finer size fractions, is a useful property to characterise the mechanisms of rock breakage. In the past, researchers have made assumptions with regard to the shape of fragments in order to estimate surface area, such as that all fragments are the same shape or all fragments are spheres. Often these assumptions were developed with inappropriate measures and returned considerable variability and error for the calculation of surface area. This paper reports a model to estimate fragmentation surface area from sieve sized raw data and a density measurement, with experimental validation down to a size fraction of -45 + 38 ?m in a range of rock types. After characterisation of particle shape, a range of fragment shapes was found to be in each size fraction. Nevertheless, in the ?2 sieve series the average fragment mass, volume and the size fraction standard deviations could be predicted reasonably accurately. Ellipsoid geometry was used to describe particle shape. Using these parameters and the number of fragments (also predicted) in each sieve size the individual surface area of each fragment was simulated.

Sep 13, 2010

Humankind's interest in measurement of human physical strength probably dates to the first humans. At that time, life was truly a struggle in which the fittest survived. To a great extent, fittest meant strongest. Interestingly, current interest in human physical strength in the workplace stems from 1970-1980s vintage research demonstrating that persons with adequate physical strength are less likely to be injured on physically demanding jobs. Survival in many modem workplaces may still be a case of survival of the strongest. There is, however, a flip side to this issue - that persons with limited strength are more likely to be injured on "hard" jobs. To address this problem, we can apply what we know about physical strength to job design. "Hard" jobs can be redesigned to be within the physical strength capability of most people. Since physical strength is important to these jobs, we must find ways to quantify it through testing. This publication concerns human physical strength testing. Its purpose is not to recommend any particular type of testing, but rather to describe the types of testing available and their uses. It is up to each individual user of strength testing to decide which testing technique is most appropriate for his or her particular application. This booklet discusses four types of strength testing: isometric, isoinertial, psychophysical, and isokinetic. Human Strength Before describing the different types of strength measurement, we must define the term "strength" and explain the concept of strength measurement. Strength is defined as the capacity to produce force or torque with voluntary muscle contraction. Maximum strength is defined as the capacity to produce force or torque with a maximum voluntary muscle contraction.(1,2) These definitions include some key words that must be explained. A voluntary muscle contraction is "voluntary." When a person's physical strength is measured, only the effort the person willingly puts forth at the time is measured. Thus, when we test a person's "maximum strength," we are not measuring his or her actual maximum, but some lesser value representing what he or she is comfortable expressing at the time with the existing equipment and environmental conditions. Interestingly, when researchers startled persons being tested (e.g., by setting off a starter's pistol behind them), they have found significant increases in measured strength.(3) It has been hypothesized that the lower strength displayed during normal testing provides a margin of safety against overloading and damaging muscle tissue. The test equipment and the tested person's familiarity with the process also influence the "voluntary" strength output. The interface between the tested person and the test equipment is particularly important. A poorly designed interface induces localized tissue pressures that vary from uncomfortable to painful. In this situation, testers are measuring voluntary discomfort tolerance - not strength. It is important for strength researchers to keep the "voluntary" nature of their data in mind when they are designing their equipment and protocols.

Jan 1, 1998

By Suk han Jang

This paper describes the tower foundation design and construction experience for the 345kV Youngheung marine transmission line, which has been in commercial operation in Korea since July, 2004. This transmission line was designed and constructed to meet the rapidly increasing power demands of metropolitan areas and supply stable, bulk electric power from the Yonghung thermal power plant into metropolitan areas. This transmission line passes over the west sea, Lake Sihwa and over land. In order to successfully complete this project, and to safely support the tower during severe maritime conditions, several types of tower foundation such as Pad and Chimney foundation, Pier (Cylindrical) foundation, R.C.D foundation, Jacket pile foundation and Steel pipe pile + concrete mat foundation were developed and used. As the world?s first and longest marine transmission line, the 345kV Yonghung marine transmission line operates successfully, thanks to several high-tech civil engineering technologies and KEPCO?s accumulated experience.

Jan 1, 2007

By Syamujulu. M

Subsequent to the unbundling of the Zambia Consolidated Copper Mines (ZCCM) and the privatization of its constituent parts, the Konkola Copper Mines (KCM) represents a third of the original conglomerate. Now run by private hands as a sub group of Vedanta Resources Plc of India, KCM is strategizing on how best to deal with the operational issues of the organisation to resolve some of the difficult, logistical, environmental, mineralogical and metallurgical problems being encountered to tum them into opportunities as the company turns around. This paper reviews the options being put in place to provide appropriate solutions and strategies including the treatment of the highly siliceous low energy copper belt concentrates in its mining operations in Zambia.

Jan 1, 2007

By M J. Van Der Merwe

The mining industry is facing a serious skills resource shortage, growing commodity demand and cyclical prices. This makes focus and allocation of resources in the early stages of project development very important. To assist with these six key elements in the project prioritization process is proposed, namely: 1) Define the project vision, objectives and business case, 2) Determine the potential show stoppers, 3) Determine the key value drivers, 4) Track changes and provide regular feedback, 5) Evaluate the alternatives and, 6) Ensure proper gate management governance at the decision point. Incorporating these elements in the project development process will assist in resource allocation and focus on the high value aspects of projects and alternatives during the early stages of the project development lifecycle. Keywords: Resource allocation and focus, vision, show stoppers, value drivers, project prioritization, linear programming, business case modelling, management decision.

Jan 1, 2008

Some design and feasibility studies have been made into possible methods of economic recovery of sulphur from smelter gases emitted at Western Mining Corporation's Nickel smelter at KalgoorIie in Western Australia. The smelter discharges some 330 000 tonne/yr of sulphur dioxide in a stream of approximately 6 per cent by volume of S02.Three possible recovery methods have been considered:1. The manufacture of sulphuric acid using the contact process.2. The concentration of sulphur dioxide to a pure form using dimethyl aniline as an absorbing medium.3. The reduction to elemental sulphur using natural gas as the reducing agent.Design studies were carried out by final year chemical engineering undergraduate students at Royal Melbourne Institute of Technology (RMIT) in 1981 under the supervision of the author and other teaching staff of the chemical engineering department. These studies indicate that sulphuric acid manufacture is the economically preferred recovery route.Markets for sulphuric acid include several potential mineral processing applications and the established fertiliser industry.Sulphuric acid is currently manufactured in a number of plants located at coastal regions of Western Australia using imported sulphur. The sulphuric acid is then used for superphosphate or titanium dioxide pigment manufacture at adjacent plants.The possibility is considered of manufacturing superphosphate at Kalgoorlie from locally produced acid obtained from the smelter gases and from phosphate rock railed to the site from the coast. The advantages of such a scheme include improved scale and technology of operation compared with some existing coastal operations, use of a waste material to replace imported sulphur, and avoidance of costs and hazards associated with railing large quantities of sulphuric acid.

Jan 1, 1983

By Peter Cunningham

General Description of Projects The objective is to streamline data transfer within our Process Control and Business Systems for the purposes of tracking actual production, reducing manual record keeping, improving process control and improving vehicle maintenance. This presentation focuses on two implementations of mobile equipment data acquisition systems which make use of industry standard data models and data transport protocols. Pilots are part of the Mines Technology Roadmap to improve our mining operations ?Enabling technologies and pilot of key systems

May 1, 2013

By W. W. Adams

[The sfxteeith e-mud ?7ntior_,il SnS~ty Cn~potitior,, cohduc ted by th Bureau of Mines, United Stntes'I3epnrtzel?t oL' the Interior, hstc fist been closed, and the resvlt s reveal tbt t!:e co~yafir,~ compzniqs had fewer accir'.ents in prnyort?lon to t2.o numbcr,of nkr-l:q?lr~1 1:9:='czd thm in my other ycryx in t3o r~cordc of the conlcst, Pheco zrzu-J. con:estn me thus aclr,i-cvir.c; Shc?r purpoao of ~romo tine w.fe ty in t5c nip-i~y induc tq*.]

Jan 1, 1941

By E. Mongilardi

The construction of large underground openings through cohesionless or weak cohesive soils and under the water table in particular, often requires a ground improvement to be done from the surface or ahead of the excavation face in tunnelling problems. To this purpose various injection procedures have been used in the past and new outstanding techniques have been developed recently, such as "jet-grouting", extending the feasibility range. The paper presents a review of basic principles and practical design criteria with particular reference to the newest trends of development. Case histories have been selected within the experience of specialist contractor Rodio Co. showing the variety of problems solved by manifold grouting procedures and layouts, in widely different soils ranging from the sandy-gravelly alluvia of Milan to the soft marine clays of Singapore.

Jan 1, 2010