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By Tom Skodack

Mine and tunnel contractors face a complex environment-one in which economic risks are high, operating costs grow ever higher, ore grades are lower or recovery more difficult, and civil construction projects are intensely competitive on a world-wide scale. Within the context of this environment, the risks and rewards of proper machine selection for rock excavation have become proportionately large. Speed, depth and scope of analysis, and extensive supporting information are indispensable in the selection process. Equipment designs and their applications are also myriad and diverse. Several equipment alternatives and excavation techniques may have to be evaluated at once to choose the most cost-efficient approach. The following examples are typical of the current demand for more detailed equipment analysis: • An aggregate supplier starts a new quarry. He knows his targeted tonnage, blasting restrictions, and previous operating costs from other quarries. But he must improve on his old costs. What drill pattern, hole size, and bench height will give lowest cost per ton? How many crawler drills and what type will produce this tonnage most efficiently? • A mine is using a fleet of twin pneumatic ring drills for long hole drilling to initiate their cave. The mine is facing both air shortages and increasing operating costs with decreased efficiency in the ring drill fleet. If they invest in new hydraulic long hole drills, what impact will each drill unit have on production? Each twin drill unit? What configuration gives best operator efficiency and subsequent reduction in manpower? Which configuration gives the best return on investment? • A tunnel contractor is bidding a long straight water tunnel by conventional drill and blast methods. What is the optimum number of drill booms for the tunnel cross section and excavation schedule? How many rounds per day can he achieve? What are his total project drill, blast, and muck costs? In the past, such questions could be answered, but only approximately at best. One good prediction could involve many hours of laborious calculations that had to be repeated each time a new parameter was introduced or an existing parameter changed. In 1980, increasingly complex analysis, coupled with increasing need and quick response times demanded by industry, led Atlas Copco's project department to turn to the computer. New computer programs based on theoretical considerations and three decades of worksite performance data were developed for evaluating mine and tunnel contractors' equipment needs, productivity, and partial or total operating cost calculations for most conventional drill and blast excavation techniques-including shot rock loading and transportation. This Computerized Analysis of Rock Excavation-or CARE-program has since been available to the mining and construction industry. From each program specific results can be pre- dicted, including: • Productivity Calculations-Rock drill penetration rate for a given drill, hole size, and rock type, optimized for the best drill steel life; net machine productivity (drill-out time or drill meters-footage-per shift); total drill round time, including charging, blasting, loading, and haulage; suggested drill pattern, computer printed, including hole size for a given rock drill, rock type, and associated blasting restrictions for either drift rounds or benching applications; long-hole drill meters (ft) per drill shift; breasting down (upper drilling) drill meters (ft) per drill shift; and comparison between continuous loading machine capacity and LHD capacity. • Operating Cost Calculations-Operating costs expressed as cost per drill meter (ft), cost per cubic meter (cubic yard) of excavated rock, and cost per meter (ft) of tunnel advance. These costs may be calculated using as many cost centers as the mine, quarry, or tunneling contractor wishes. Specific operating costs may cover drill rig operating costs only, less capitalization; drill rig operating costs, including amortized equipment investment; drilling and blasting costs; drill, blast, load, and haulage operating costs; long-hole drilling operating costs per drill meter (ft) or per blasted cubic meter (cubic yard) of rock; and loading and transport operating costs. In all the above cases, any number of cost and capacity calculations may be run by simply changing important cost center variables to judge their net effect. Accuracy as a Function of Input Data and the Statistical Data Base Accuracy of a projection clearly depends heavily on the data base from which the projection is drawn.

Jan 11, 1982

By Robert F. Conley

In the mining, manufacturing and application of inorganic pigments, dispersion contributes significantly. This is especially true with mineral pigments because of the variety, in slurry operations required for their processing. Such operations include any of the following: (1) mine-transport (2) wet grinding (3) flotation/beneficiation (4) wet magnetic separation (5) selective floculation (6) size classification (7) chemical processing (8) spray drying Dosage levels and general economics of dispersant use are broadly variant, being dependant upon the agents employed, from the simplist, i.e., sodium silicate or sodium carbonate, to the more complex, as polyacrylates and organo-phosphates. In certain unit processes the dispersant must exhibit unusual chemical stability and persistence, e.g., in protracted pigment slurry shipments. In others, the agent should be fugitive to prevent secondary reactions from occurring, e.g., with high temperature calcination where alkali salts can act as aggregation fluxing agents.

Jan 1, 1985

By Walter N. Campbell

The Simon Silver Mine is located near Mina, Nevada, approximately 50 miles northwest of Tonopah and 40 miles east of Hawthorne. It is an old property which was last worked in 1932 and closed operations due to problems arising from low metal prices. Federal Resources Corp. acquired the property in 1963 and undertook a completely new development program since the old surface plant and underground workings were beyond feasible repair. The deposit of silver, lead, zinc and copper is predominantly replacement of limestone. In the summer of 1964, a new surface plant was constructed and on December 2, 1964, sinking of a three compartment vertical shaft started and was completed to a depth of 1088 feet in April of 1965. Following the sinking program an 850 foot crosscut was driven to intersect the mineral zone on the 1000 level after which drifting, crosscutting and raising totaling some additional 4280 feet has been completed along with considerable diamond drilling and long holing into the walls. To date, two ore bodies have been encountered and test stoping operations are underway together with development of the 800 level for servicing, ventilation and access. The present development of ore is directed towards substantiating sufficient reserves to warrant the construction of a flotation mill.

Jan 1, 1967

By Jaime Lomelin

[First of all I want to thank the Society of Mining Engineers of AIME for the opportunity to present what Industrias Penoles, S.A. is doing in Mexico to reach the basic objetive of the enterprise without compromising, in short or long term, the living conditions of the community or attempting in an irreversible form against Nature. Industrias Penoles, S.A. is one of the largest mining and metallurgical companies in Mexico. It was founded in 1887 and at the turn of the century installed a lead smelting operation close to the village of Torreon, which became city five years after the start up of the Penoles smelter. Now Torreon has a population close to 300,000 inhabitants. In 1974 Penoles is still the largest industry in Torreon and the dynamic growth of the city is close related to this factor. Today Penoles in Torreon has a lead smelter with a capacity of 130,000 metric tons/year of bullion, an electrolitic zinc plant of 105,000 metric ton/year, and it is modernizing its lead smelter to control pollution and expand it to 190,000 metric ton/year of bullion including all the services and refinery. The Penoles complex in Torreon is the biggest in the non-ferrous metals field in Latinoamérica.]

Jan 1, 1974

By Hans von Michaelis

The revolution in development of new technology and practices in the gold mining and metallurgy industry continues unabated despite the ups and downs in the gold price. Some of the new cutting edge technologies are listed in Table 1 overleaf. There is room to discuss just a few of these here, but many more are identified and described in RANDOL (1992). Cutting edge advancements in gold recuperation, can be sorted into three categories. The first category includes fundamental advances that offer major improvement with significant economic benefits. Second would include evolutionary developments that offer smaller, but nonetheless commercially valuable improvements. Finally there are those "advances" that are interesting but of trivial or question­able economic benefit to industry. It is essential to adopt a "systems approach" philosophy towards developing and applying new technology. Practical innovation often comes about as a result of having to solve a problem. Innovation for innovation sake is an ego trip. Environmental management has become an important part of the system and the environmental implications of new processes and practices in the mine and mill have to be carefully considered for potential benefits and/or liabilities.

Jan 1, 1993

By A. Wang

This paper defines the elements of a basic economic model for decision-making when considering a methane drainage system for an underground coal mine. A drainage system will require significant capital and operating expenses; hence the decision to utilize drainage must be made carefully. The model outlines the basic structure of decision-making and considers the costs and benefits when the methane is marketed and when the methane is vented to the atmosphere. The effects on mine safety and the dust levels in the mine are also considered, both in a general format and as economic variables. Sources of information for executing this decision-making are provided for an actual mine decision.

Jan 1, 1997

By Arthur S. Cornford

According to Arbiter (Reference 1), the ball mill was invented by Brückner in Germany in 1876 and was first used in the United States on ores about 1905. The basic concept was a simple rotating cylindrical drum in which the tumbling action of the charge of material and grinding media resulted in size reduction of the material. Despite the very low mechanical efficiency of this method a number of factors have caused the tumbling mill to remain, by far, the most widely used piece of equipment for mineral grinding. The principal factors influencing this situation have been simplicity of design, ease of manufacture, ready adaptability to familiar material handling layouts and the absence of practical alternatives acceptable to the industry. In the early mills, the material was ground in batches, the mills being charged and discharged through doors in the shell. The shell was supported by means of solid trunnion shafts resting in plain bearings and the drive was accomplished through one of these shafts. In some later batch mills, the mill shell was supported on rollers which were also used to drive the mill. At an early stage, continuous operation was made possible by feeding and discharging the mill through hollow trunnions, the method still in most widespread use. The mechanical and structural design of the early mills was not an onerous engineering task. Norse sense and good practical knowledge were key qualifications. The mill shells had to be heavy enough to withstand the physical abuse they would receive in the field and the bearings had to have low enough unit pressures and sufficient wear retol to ensure several months of operation before the need for replacement occurred. When these requirements were satisfied, stresses developed in the equipment during operation were insignificant and the majority of structural failures were probably due to the use of inferior materials in manufacture. Over the years, the ever present demand for increased productivity has resulted in a steady Increase in the size of units of production equipment, including grinding mills. Arguments have been presented elsewhere, for and against the Idea of a high throughput single line grinding operation as opposed

Jan 1, 1972

By R. J. Snoby, P. Grotjohann

In processing heavy-mineral sands, the low feed concen¬tration and respective high value of the desired minerals require high-capacity production and sharp classification/ separation techniques to reduce the specific production costs. This paper describes the new allfux® separator, which can economically accomplish these criteria. The separator is a two-stage process that combines rising current and fluidized-bed technology. This allows for the treatment of ex¬tremely high mass flows in a single unit. This paper reports on test work performed on coal, iron ore and heavy minerals.

Jan 1, 2000

By Jan A. Nemcik

Steel mesh has been used successfully for many years to control friable roof conditions and prevent loose roof and rib material from caving into the roadway. Despite its extensive use, the installation of steel mesh is difficult to automate and many other products have been evaluated as an alternative for skin control. Ideally, the properties of these new products should be similar or better than those of the steel mesh. In particular, development of a strong and resistant shell that minimizes movement along the fractured rock and coal surfaces between the bolt anchors is recommended. A strong surface adhesion and the strength of a reinforced polymer skin can provide the necessary toughening mechanism required to enhance roadway surface support by forming a reinforced polymer/rock surface layer. Most of the Thin Spray-on Liners (TSL) evaluated in the mines are weak with slow curing times, and the plastic mesh currently used to support the coal ribs is relatively weak. Therefore, neither material can seriously compete with steel mesh. Currently, a new polymer product that cures in seconds and forms an instantaneous strata binder that surpasses the properties of steel mesh is under development at the University of Wollongong.

Jan 1, 2009

By Hugh W. Rimmer

The design of comminution circuits and the evaluation of alternatives should be based on state-of-the-art equipment and appropriate design criteria - considerations that are often neglected by today's designers. This paper critically reviews common circuit designs, evaluates various alternatives for difficult-to-treat ores, and discusses the factors that should be considered when developing new plant designs or auditing existing plant performance. Data obtained from laboratory, pilot and plant-scale test work on a wide range of ores and circuits are used to justify the author's conclusions.

Jan 1, 1995

By Stephen H. E. Phillips

Geological and hydrological conditions in the strata overlying the Salado Formation vary considerably in the Carlsbad, New Mexico area. The first four shafts sunk at international Minerals and Chemical Corporation's property have been located in competent and essentially dry conditions, while other shafts on adjacent properties have had such adverse conditions that ground freezing has been chosen as the water and ground control technique for shaft sinking. At the location of the IMC No. 5 Shaft there has been extensive-erosion and salt dissolution in the Rustler Formation which has led to collapse of some zones of the strata. Both ground freezing and pregrouting were considered as alternative methods of stabilizing the extremely poor ground conditions and controlling the potentially very heavy water inflows it was decided that pregrouting the shaft was feasible and would offer substantial cost and time saving over a ground freezing technique. This paper describes the pregrouting techniques used and illustrates the requirement for flexibility in a grouting program so that it can be codified to reflect any new or additional information which is obtained during the progress of the grouting.

Jan 1, 1984

By Ronald C. Bethard, Kenneth W. Ely

The liberation of methane during underground coal mining causes serious safety concerns. During a mining cycle, with mechanized mining equipment, thousands of cubic feet of methane are released from coal seams, discharged to return air courses, and vented to the atmosphere through mine fans. This has been the traditional way of removing the explosive hazards of methane gas from the mine. Through horizontal and vertical degasification techniques, this hazard can often be handled in an equally safe and much more profitable manner. Basically, degasification allows for the controlled reduction of inseam methane content of coal prior to its mining. It is the responsibility of mine management to evaluate these degasification programs and ensure that the program itself does not introduce some new risk to the mining process. The removal of methane gas from underground coal mines using horizontal and vertical degasification is a relatively new concept. Products and systems used in degasification continue to evolve. Site conditions vary also, so no one system or equipment can be said to be the safe answer for degasification in all situations. A constant process of cooperation and evaluation by mining and degasification management should result in a safer and more profitable mine.

Jan 1, 1989

By G. Ansong, P. K. Achireko

The authors present a new mineral price model, compare it with time series and naive models, and analyze the effects of the forecasting models on mineral project evaluation. Mineral commodity prices are volatile, which means that the results of evaluation tools that do not treat the stochasticity of metal prices rigorously may be misleading. But, in mine valuation, commodity price forecasts are required to assess the economic viability of a project. In this study, a new mineral forecasting method, called the MNDRVG-MFNN-RM model, which incorporates randomness, neural networks and regression models, is introduced. The MNDRVG-MFNN-RM model, a naive method and time series model were used to forecast gold prices for two successive years for the evaluation of a proposed open-pit mine. The MNDRVG-MFNN-RM model yielded the best results among the three methods. It produced the true optimum pit limits and an optimum pit value slightly less than the true optimum value. The main novelty of the methodology is the simulation and rigorous analysis of the randomness property associated with mineral prices to reduce the estimation and forecast errors, an important contribution to mineral venture evaluation, mine planning and design.

Jan 1, 2000

By D. J. Crawford

The Lucerne Valley Operations of the Minerals, Pigments and Metals Division of Chas. Pfizer & Co., Inca, are located about 5 miles south of the town of Lucerne Valley, California. These operations consist of several limestone quarries, a whiting plant which produces finely pulverized limestone products, a-kiln which produces granular quicklime and lime products, and maintenance shops, warehousing, shipping, and office facilities. Construction of the Lucerne Valley plant began in 1961 as the result of a decision to utilize large undeveloped reserves of limestone in that area. Quarry development was started in the following year; and by 1965, Lucerne Valley had become the principle limestone and lime facility of the Western Operations of the Minerals, Pigments and Metals Division.

Jan 1, 1967

By G. Wang

Industrial minerals processing has gained importance lately, not only due to its wide range of new and regular applications in processing different industrial minerals, but also due to the strict specs under which products are commercialized. Among the processes applied to industrial minerals, flotation is a leading technology. The laboratory study and commercial operation demonstrate that the sulfonated reagents are very effective collectors for industrial minerals. This paper compares synthetic petroleum sulfonate with fatty acid on iron reduction in glass sand processing and describes the effect of conditioning pH on iron reduction using synthetic petroleum sulfonate as collector, the effect of molecular weight of natural and synthetic petroleum sulfonates on their flotation performance and the enhancement made for certain products.

Jan 1, 2011

By R. A. Matuszak

U.S. Government sponsored studies proclaim large reductions in surface mine productivity. Consulting studies place a large share of the blame on increased governmental regulatory activities and on inexperienced, improperly train people. Union rules, which allow indescriminate bidding for job openings, seem to be a major factor causing the lack of experience in spite of elaborate training programs.

Jan 1, 1982

By R. S. Farinato

Thionocarbamate flotation reagents have enjoyed a niche position in the recovery of copper sulfides and activated sphalerites since their introduction in the mid 1950's (Harris, 1954). Thionocarbamates containing an allyl group (-CH2- CH=CH2), introduced recently Lewellyn, 1985; Nagaraj, 1988; Avotins, 1991), are used commercially as collectors for copper sulfides and activated sphalerite. Laboratory flotation tests and plant usage have demonstrated that allyl-containing thionocarbamate collectors exhibit certain unique properties that distinguish them from the corresponding dialkyl thionocarbamates. Spectroscopic (FTIR, XPS) and wettability studies of N-allyl iso-butyl thionocarbamate (AIBTC) and its saturated analog N-propyl iso-butyl thionocarbamate (NPIBTC) adsorbed on copper at pH 9 were performed in order to investigate whether there were any fundamental reasons for these differences. Flotation tests were carried out on chalcocite, copper ore and an activated sphalerite.

Jan 1, 1993

By A. C. C. Pacheco, L. C. Bertolino, M. L. Torem

On account of geological characteristics, Brazil is a country of large deposits of high quality kaolin, with the larger ones being located in its northern region. In the last years, kaolin beneficiation and production area is receiving great investments, aiming at a high quality kaolin production to be used in the paper industry, mainly intended for the foreign market. After the conclusion of expan- sion programs and with the advent of new production areas, Brazil is very soon expected to come in second place in the kaolin world production ranking.

Jan 1, 1998

By Ronald G. Schmidt

AND SOME RIN UP HILL AND DOWN DALE, KNAPPING THE CHUCKY STANES TO PIECES WI' HAMMERS, LIKE SAE MANY ROAD MAKERS RUN DAFT. THEY SAY IT IS TO SEE HOW THE WARLD WAS MADE. Sir Walter Scott St. Ronan's Well - 1824 In the minds of many, geologic exploration has advanced little since the early nineteenth century. In truth, despite the development and refinement of new and potentially valuable technological tools, the approach or philosophy of the explorationist has received meager attention in professional literature. In many areas, the explorationist relies upon experience, subjective judgement and general intangible inspiration, often traveling together under the misleading pseudonym of "art," in achieving both an exploration plan and in making the myriad day to day decisions necessary to the execution of that plan. Without a solid, objective basis for decisions, exploration under this concept is little more than guesswork largely by intuition, and it is small wonder that many exploration programs flounder in a sea of over-expenditure inefficiency or fail to fulfill their expected goals within the funding which has been provided. From a rational management point of view, such a state of affairs is frustrating and inconsistent with the application of the same scientific principles which are presumed to be the basis for the exploration methods which are used. This somewhat presumptuous point of view cannot be extended as a general condemnation of the many exploration programs which are both technically and economically successful. On the other hand, the

Jan 1, 1968

By Patrick M. James

Many in mining believe that the industry is slipping behind in public image, in public mineral education and, particularly, in mining's basic right to do business. It is critical to turn things around - to change the rules of the game soon - before mining loses any chance of recovery. In the industry's experience, there is a technique of project development and operation that can help gain ground on public opinion. Only recently has this technique had a name, and that is sustainable development. What is sustainable development? Sustainable development is broadly accepted and supported by the international business community. And significant thought and work has been devoted to the subject. Research into the topic was initially confusing because the definitions of sustainable development are written in terms the writer, and his or her constituency understands. To some, it refers to environmental protection. To others, it is about social responsibility. And to the developer, it is about economic benefit. Slowly a theme emerged from the research that seemed to be part of all the definitions. That theme has three parts. First, the development, whatever or wherever it is, must contribute economic value to the developer and the stakeholders of the development. Stakeholders in this context include employees, neighbors, residents of the surrounding area, citizens of the country, suppliers and all others affected by the development. Next, sustainable development must contribute environmental value. This means that at a very minimum it must be neutral and not cause irreparable damage. And last, and what is new for miners and most other businessmen, it must contribute real social value to the stakeholders. How to use the concept? With that three-part theme as a working definition, the mining industry must find ways to use that “the challenge is for an individual company to translate what sustainable development means for them. There is no one model..." Donald W. Gentry is president and chief executive officer of Polymet Mining and former professor emeritus of mining engineering at Colorado School of Mines. He added: "While simple to state, the concept is anything but simple to implement. Present trends indicate ... one wins the sustainable development argument by staking out the high ground early..." In other words, start using sustainable development principles at the beginning of the project. New ways of doing business The mining industry's challenge is to implement sus¬tainable development universally around the world. Paternalism as a way of doing business is dead and a new model of doing business is emerging. All types of businesses are learning to deal with the stakeholders of new developments. Mining cannot be an exception to these trends. To understand how the international mining business came to sustainable development, it is useful to look back a few years. For many North American mining engineers, there were few opportunities for foreign assignments from the 1960s to the 1980s. American companies had been asked to leave many of the Latin American countries. Africa was going through a continent-wide upheaval. The Soviet Union and China had Eastern Eu-

Jan 1, 2000