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By Sheldon P. Wimpfen

Back in 1970 Congress passed the National Mining and Minerals policy Act, which had as one of its basic tenets to rely on a strong and stable private minerals industry for the development and production of our mineral resources. Since then, a substantial amount of legislation has been introduced that impacts on the minerals industry. Although most of the bills proposed are not passed into law, each bill affecting minerals and mining is given careful review by the Bureau of Mines. Comment is forwarded with the object of being helpful to legislators by providing our assessment of the probable impact of each bill proposed along with suggestions to improve them. Actually few bills introduced become law. For example, in the 93rd Congress 4,260 bills were introduced in the Senate and 17,690 in the House. In the final accounting there were passed 123 private laws and 649 public, 3 percent of the bills introduced. There would be little merit here in attempting to analyze each mineral-related bill that was proposed. Many are similar and aim at making a certain aspect of our minerals activity fit needs. So, to simplify the task the many bills have been grouped by subjects. Slide 1 shows the principal topics and the number of related bills introduced. Putting it altogether, there are 26 principal subjects and almost 200 bills. And these numbers are probably off somewhat, as this accounting was made early in December.

Jan 1, 1976

By J. W. Lowry

After years of processing copper porphry ores, the Ray concentrator of Kennecott Minerals Company installed a concentrate regrind mill in its flotation circuit. The first cleaner concentrate is reground rather than the usual rougher concentrate. An additional cleaning of the reground product yields an increase in copper content of the final concentrate and a significantly lower insol content. The desired goal of decreasing the energy requirements for smelting the concentrate has been achieved.

Jan 1, 1980

By J. L. Schroder, William J. Halvorsen, Wiliam W. Lyons, Kent C. Ware, Sheridan A. Glen, Donald C. Simpsom

The prospects for near-term growth in coal demand are exceptional: the federal government recently targeted 141 oil- and gas-fired generating units for mandatory conversion to coal; coal-to-synfuel developments are proceeding at a steady clip, with construction of a $1.2 billion gasification plant to begin this year in Beulah, ND; uncertainty over nuclear power and stratospheric oil prices enhance the steam coal market; the export market is ripening; and an influential new political force (the Senate Coal Caucus and Congressional Coal Group) is flexing its muscles on Capitol Hill. But the rosy picture is muddled by signals, often conflicting, sent out by federal agencies. Although EPA can be credited with relaxing its grip on the Clean Air Act, its sulfur dioxide control strategy is still often at odds with the Administration's call for domestic energy (coal) development. B. R. Brown, president of Consolidation Coal Co., sums up the situation: "Every mule is pulling in a different direction." Often in the midst of the fray is the small operator who has been hardest hit by the stagnation of coal markets. Layoffs, shortened work weeks, and mine closures were rampant in the eastern and midwestern coal fields, even among large producers. The longstanding boom in western coal was tempered during 1979 by a noticeable slowdown in announcements of new mine construction. The prognosis: Eastern coal will remain in the doldrums for quite a while to come as it works off some 90 Mt of overcapacity. Midwestern coal will fare no better due to the regulatory-influenced appetite of midwestern utilities for low-sulfur western coal. This displacement should ease, though, as new power plants equipped to burn high-sulfur coal come on line in the years ahead. In the West, the National Coal Association projects production to increase a healthy- 10% this year, although mine-to-market transportation looms as the single largest stumbling block to marketing efforts. Fatalities Up 40% in 1979 The National Coal Association estimated total coal production in 1979 at 671 Mt, an increase of 13% over 1978. Of this total, the East and Mid-west accounted for 476 Mt (71%) and the West produced 195 Mt (29%). With the consistent rise in western production playing against flat outputs in the East and Midwest, underground mining's share of total production continues to slip and is expected to account for only 38-39% in 1980. Incidence of deaths and injuries at US coal mines soared in 1979 over 1978 rates. MSHA figures (still subject to final adjustments) reveal a death rate of 0.07 per 200 000 man-hours, up 40% over 1978's 0.05 figure. MSHA chief Bob Lagather attributed the death incidence to the large number of new coal mines put on line in 1978, which he estimated at between 350 and 400. Nonfatal injuries rose to 8.48 per 200 000 man-hours, up about 15% from a 1978 rate of 7.35. In absolute numbers, MSHA counted 144 fatalities and 18 111 lost-day injuries during the 1979 calendar year. The 144 coal mining deaths in 1979 is the highest number of coal fatalities at US mines since 1975.

Jan 5, 1980

By J. N. Eskilsson, W. P. Chen, J. L. Kaplin, V. S. Romero

The Massachusetts Water Resources Authority is currently improving its primary water supply system for the Boston Metropolitan area. The improvements planned by the Authority, which provides water for 46 communities and over 2.5 million people in eastern Massachusetts, include the MetroWest Water Supply Tunnel (MWWST) to provide redundancy in the transmission system, a large capacity water treatment plant and extensive covered storage facilities. The 28.3 km (17.6 miles) long, mostly 4.3 m (14 ft.) I.D. MetroWest Water Supply Tunnel will allow repair of the aging Hultman Aqueduct, which for 56 years has served as the transmission main from the water supply reservoirs to Boston. On completion of the tunnel, the old pipeline aqueduct will be repaired and brought back into service as a parallel, redundant transmission main. This paper describes design considerations and the design process for pressure tunnels in general and the MWWST in particular. It provides an overview of how the design of pressure tunnel and shaft components progresses.

Jan 1, 1997

By Herb Wilson

The Klondike symbolized one of mankind's driving forces - the desire to lay one's hands on a scarce resource, gold, in that case - and in doing so to make some money along the way. It can be argued that construction aggregates - a once lowly and ignored sector of the natural resource industries - have become the desired targets of their own "Klondike." This began in the 1970s and accelerated to a frantic pace in the 1980s. The scope of industrial minerals is very wide. It ranges from high value minerals such as talc, bentonite and kaolinite to the truly humble minerals of sands and gravels, limestones and granites. Their major end uses are in construction aggregates. A rich variety of different mineral types all make good construction aggregates. However, those successfully used have two fundamentals in common: • Their technical characteristics are appropriate for the requirements of their end use. • They are located within an economic distance from the market. The North American market This is the largest construction ag¬gregate market in the world. Consumption in 1990 reached 2.2 Gt/a(2.5 billion stpy). This rate of consumption has grown steadily over the past decades. In the United States, from 1963 to 1989, it averaged a 1.6% compound growth rate. Within this long-term trend, there are business cycles, because aggregate demand is closely linked to economic strength or weakness. The North American market also displays the greatest per capita demand for aggregates when compared to the major industrial economies (Table 1).

Jan 1, 1993

By A. F. Ogg

The installed world steel capacity remains 20% above the present world steel demand. Energy costs have risen enormously in recent years, as illustrated in Figures 1 and 2. The role of the sinter plant is becoming more exacting as it becomes vital to minimize energy consumption. Continuous grate sintering, although pioneered in the United States, has always been the second grade burden preparation route, due to the predominance of easily up- graded ores which were more readily agglomerated by pelletizing. To achieve blast furnace performance up to best world standards, sinter of consistent high quality must be produced with virtually no atmospheric pollution. The plants must be capable of achieving this demanding level of quality whilst utilizing high proportions of revert materials, iron ore concentrates and fluxes . However, with the present difficult economic climate in the iron and steel industry, the economic production of sinter and ultimately steel is becoming increasingly important. The iron and steel industry is looking closely at costs and is identifying the need for sinter plants that will cope with a wide range of sintering materials to give the cheapest blend at varying output levels dependent upon demand. In order to meet these requirements, sinter plant builders are designing plants with particular attention on flexibility.

Jan 1, 1980

By R. Canello, J. Jenkins

El Abra has the world's largest leach, solvent extraction and electrowinning facility, The crushing plant capacity is 120,000 metric tonnes per day and the cathode production capacity is 225,000 metric tonnes per year. The El Abra mine and plant are located in the Province of El Loa, in Region I1 of Chile, 55 km. north of the city of Calama. The ore deposit outcrops on the southern slope of Cerro Pajonal at an altitude of 3,900 to 4,100 meters above sea level. The processing plant and camp facilities are located at a lower 3,300 meter elevation on an alluvial slope, 15 km southeast of the deposit. The operating company, Sociedad Contractual Minera El Abra, is 51% owned by Cyprus Arnax Minerals Company through the Cyprus Climax Metals Company subsidiary and 49% owned by Corporaci6n Nacional del Cobre de Chile (Codelco). The present paper describes the ore reserves, mine operations, crushing, leaching, solvent extraction, electrowinning and infrastructure facilities.

Jan 1, 1998

By E. Kurt

The field of percussion rock drilling is subdivided into two areas of application; that which takes place on the surface and that which takes place underground. Surface drills are used in quarrying, highway construction, and maintenance work; underground equipment in mining and tunneling work. Two basic principles are involved in the operation of all percussion drills. First, the principle that reciprocates the impacting piston and second, the principle that causes the drill steel and bit to rotate. The back and forth motion of the piston is accomplished by a self-acting automatic valve that admits air alternately to each end of the piston (Figure 1). Drill steel and bit rotation is imparted by an integral ratchet mechanism (Figure 2) in the so-called "rifle bar" machines (Figure 1) or by a separate pneumatic motor in "independent rotation" drills (Figure 3). While rock drills are subject to all kinds of physical and operational abuse, they are most sensitive to faulty lubrication. Proper lubrication is the single most important factor in the longevity of a percussion drill.

Jan 1, 1970

By B. L. Gibbs

The mining industry is constantly in a state of flux -boom or bust; mine openings and closings. Part of the reason is the nature of ore deposits -they are there or they are not. Once they are mined, they are reclaimed and the move is on to the next deposit. Risks are usually high, and payoffs can be great or not so great. Many factors go into making a property payoff, and mining companies are continually searching for ways to remain profitable as long as possible. Computers and the people who can make them work are one of the ways available to improve productivity and ensure this happens. Computers have been used in the mining industry for the last 30 years (and more in a few cases). During the past 10 years, the explosion of micro-computing has changed how many mining companies do their work.

Jan 1, 1993

By Jim Morris

This paper will describe the excavation of a 5.4 percent decline at the Montanore Project for Noranda Minerals Corporation. The 5.3 m by 4.9 m tunnel was driven to provide access for the exploration of a major copper-silver deposit. Soft ground and conventional drill-blast mining were used on the 4,270 m tunnel. Ground support consisted of steel sets and concrete in the soft ground and pattern rockbolts providing the majority of the rock support. A special feature of the project was the use of conveyor haulage in conjunction with the drill-blast excavation.

Jan 1, 1993

By E. J. Onuscheck

Coal mine safety of the past was plagued by disasters that took the lives of thousands of miners. Through the years new mining methods, improved laws, and a commitment from the mining industry has reduced the frequency of such incidents to a minimum. History tells us that coal was mined in the early 1700's in Virginia primarily for use by blacksmiths -- most of that mining was done in the Richmond area. It was in those mines that methane was encountered; as workings became more extensive, methane explosions became more frequent. In the early 1800's the first recorded explosion occurred near Richmond, Virginia -- 40 men were killed.

Jan 1, 1985

By D. M. Sloan

While surety capacity for the mining industry continues to shrink, States are demanding greater financial certainty for closure/post closure obligations. To combat these demands, larger mining companies are pursuing a Mining Surety Reinsurance Program that requires a significant up front capital contribution. This paper outlines an alter-native program for middle market mining organizations. The program utilizes a “Blended Finite Risk” environmental insurance solution with surety acting as the “front” in states where insurance is not an acceptable form of collateral. Marsh proposes creating separate programs for each State requiring surety. The reason for separate programs stems from each states’ different surety rules. Insurance companies typically require at least $5 million in future value remediation liabilities for finite risk programs. Since most middle market mining companies have obligations that fall below this threshold, the Blended Finite Risk Program contemplates combining several companies closure/post closure liabilities to accomplish the minimum amount required by the insurance company. Why use a Blended Finite Risk Program? One of the primary benefits is the financial assurance that funds will be available for planned remediation. For example, the financial assurance may be required by a government agency. The certainty may help facilitate a merger or acquisition. Additionally, the funds may be part of a CER-CLA PRP settlement. In all cases, the insurer providing coverage would be a secure independent 3rd party. A Blended Finite Risk Program also provides a long-term solution – up to 30 years and in some select cases longer. The benefit to a state or the BLM is the removal of financial uncertainty. An insurance company writing the policy would have an AA or AAA balance sheet. The hardening of surety markets coupled with the tightening of financial assurance requirements in many states have necessitated the posting of 100% collateral. This program substantially reduces these collateral requirements.

Jan 1, 2004

By J. C. Motz

With ore grades continually decreasing and finer mill feed requirements, it becomes increasingly important to have the capability to handle the larger tonnages economically. With the 10 ft. Standard capable of reducing 1,633 metric tons per hour (1,800 short tons per hour) to 80 percent passing 50 MM (2 inches) and the 10 ft. Short Head following to produce a mill feed of all minus 12 MM (1/2 inch) at a rate of 608 metric tons per hour (670 short tons per hour), we feel significant savings will be realized in installation and operating costs. The largest concentration of cost in the secondary and tertiary crushing stations is the building itself that houses the process equipment. An example of the savings to be attained can be seen from an examination of a 40,820 metric ton (45,000 short ton) per day crushing plant. A total of nine 7 ft. Symons Cone crushers is used to generate 12 MM (1/2 inch) ball mill feed. The average center distance between units is 6.1 M (20 feet) and allowing a 6.1 M (20 feet) nominal distance from the centerline to the wails, the building becomes 61 M (200 feet) long. For this production rate, four 10 ft. Symons Cone crushers would be required. With the 10 ft. crushing plant requiring a center distance spacing of 7.6 M (25 feet), the building length totals approximately 38 M (125 feet). Construction costs vary depending on location, but a reduction in building length from 61 M (200 feet) to 38 M (125 feet) will result in estimated savings of between $2,500,000 and S4,000,000. While the 10 ft. Symons Cone has been involved in a number of feasibility studies for some time, the Process Machinery Division of Rexnord commenced detail design work on the 10 ft. Cone crusher in 1972. For comparison purposes, the 10 ft. and 7 ft. capacities are given in Table 1.

Jan 1, 1978

By Carl F. Austin

The subject of strata control in mining can be approached from both static or loading concepts or from dynamic or impulsive loading concepts. The fracture process itself appears to be primarily a dynamic process as is the gross creation of fractures through the use of impact, stress wave passage or in more general terms, the use of explosives. This paper presents experimental results which indicate that the understanding of the fracture behavior of rock that has been, established in the open literature is not always appropriate. In particular, the results of this experimental program have shown very interesting differences between the formation of fractures in rock and the formation of fractures in other materials such as metals and plastics which are often used as models for rock behavior studies Fracture patterns and causes of dynamic fracturing in various rock and artificial materials are presented.

Jan 1, 1965

By Francisco A. Fonseca

The Carajás Hills are in Brazil's Eastern Amazon, between the Araguaia and Xingu rivers, and parallels 5° and 7° Latitude South. A location map is given in Fig. 1. It is an area of low mountains (maximum altitude 900 meters), covered by the Amazon rain forest. Annual average temperature is 25°C, ranging from 31°C (maximum) to 19°C (minimum). Annual rainfall averages 2,000mm. Although it rains throughout the whole year, heavy rains occur from December through March. At the beginning of the 20's, Brazilian explorationists made brief geological descriptions of the area. Due to the thick soil, scarce fresh rock outcrops and the tropical forest covering a completely unpopulated area, detailed geological studies were difficult and reconnaissance expeditions were limited to the river margins.

Jan 1, 1982

By R. P. Upadhyay

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

Jan 1, 1988

By Andres Salazar, Carlos Delgado Robles, Richard K. Preece

The paper discusses the evolution of the geometallurgical model at the Escondida mine in northern Chile, the world’s largest copper producer. It highlights the transition from early metallurgical forecasting methods to a comprehensive model that includes spatial distribution of metallurgical forecasts. This model helps in planning and adapting to the variability in ore characteristics, such as hardness and mineralogy, which affect processing performance.

Dec 1, 2023

By D. L. Crouse

The worldwide talc industry has experienced significant changes since the 1980's. Consolidation of companies and operations in Europe, Australia, and North America has altered the face of supply and distribution. Imports of Chinese and Australian crude have increased competition and product options. The number of processing operations without local mines has moved competition closer to the market area. Quality controls related to ISO certification and tighter specifications demanded by the customers have altered the way our mines and mills operate. Ceramics, coatings, and paper applications continue to consume the majority of processed talc.

Jan 1, 1997

By Steve Tadolini

Underground roof falls can have devastating effects on the safety of operations personnel, and equipment, and seriously impact production. Immediate steps are usually taken to danger off and secure the area while clean-up efforts are designed and implemented. A critical step, often overlooked due to production demand, is the determination of - why the roof fall occurred so that additional occurrences can be avoided in future developments or what measures can be taken to identify areas that have similar ?symptoms?? Forensic engineering includes the investigation of materials, products, structures or components that fail or do not operate/function as intended. The authors define forensics in ground control engineering as the study of evidence discovered while examining underground roof falls by applying expert observational techniques and established mining engineering principles to determine the probable cause, hypothesize solutions, and design engineering safeguards to prevent reoccurrences. Simply stated, the primary steps in the forensics of underground roof fall techniques are: ?Assess regional and local conditions prior to the event. ? Assess post-event conditions. ? Hypothesize plausible ways in which the pre-event conditions became the post-event conditions. ?Search for evidence that either denies or supports the various hypotheses. ?Apply engineering skill to relate the various facts and evidence into a cohesive scenario of how the event may have occurred. This paper details the proposed technique by utilizing a roof fall case study that required the examination of five primary factors: mine design parameters, excavation geology, method of excavation, method of support, and mining cycle times.

Jan 1, 2009

By F. Figge, T. Hahn

In this article we present Sustainable Value, a valuation methodology to assess sustainable value creation of companies. Sustainable Development posits that decisions must not only take into account economic capital but also natural and social capital. Sustainable Value, the methodology presented in this paper, borrows the idea from financial economics that the return on capital has to cover the cost of the capital. Capital costs are determined as opportunity costs, i.e. the forgone return that would have been created by an alternative investment. By expanding the well established logic of the valuation of economic capital in financial markets to also cover natural and social capital we provide a methodology that allows an assessment of the most efficient allocation of economic, natural, and social capital for sustainable value creation in companies. We demonstrate the practicability of the methodology by the valuation of the sustainability performance of British Petroleum (BP).

Jan 1, 2005