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By Ted H. Eyde

Improving the mineral industry's tarnished image describes in a nut- shell the reason why the Speakers Bureau of the Tucson Subsection of the AIME was formed. Let's go back in time about 3 years to the fall of 1971. Literally thousands of bills detrimental to the mineral industry were being introduced into Congress and State Legislatures. Unfortunately, many were being passed and signed into law. Clean air and water, zero pollution, preserve the environment, ecology, biodegradeable, wilderness were the words that the self- styled ecologists and environmentalists were preaching. The mineral industry either sat mute or in place of acting, reacted in a way certain to attract a maximum amount of bad publicity with a minimum amount of rhetoric. A mining company president, for example, commenting on the primary air standards in Arizona was reported by the press as having said, "we'll shut all the smelters down and put thousands of Arizonans out of work if we have to meet the Arizona standards." Or another defending a poorly planned highly visible open pit nonmetallics operation, "we'll take the whole mountain down if we want to, and nobody can stop us" and still another manager of Operations, "the bottom line is all that counts, to hell with all of this environmental nonsense."

Jan 1, 1975

By Charles T. Holland

The tonnage produced on mechanized automated retreating longwall faces in the United States is growing rapidly. This time last year some 14 faces were operating, and in addition to that, three were known to be down looking towards revision or repairs before being placed back in service. These, it is believed, are now in service. It is estimated at the present time, therefore, that somewhere between 20 and 25 faces are being operated in the country. A survey made last year by the School of Mines, West Virginia University, indicated that longwall mining in general has been beset with a great many problems, some more serious than others. The problems that we propose to discuss here are those pertaining to roof and floor trouble in the tailgates. Longwalls are operating in this country at the present time under an overburden ranging from 200 feet to nearly 3000 feet. Main and tailgate entries are operating in panels of up to five each, with the width of the pillars between these entries varying from 20 to 50 feet. Face lengths are running from 270 feet to 670; actually a face 800 feet long should be possible. The most economical face is often spoken of as being around 450 feet.

Jan 1, 1969

By J. C. Monette

Stripping of gold and silver from carbon is effected by means of two main processes (AARL and ZADRA ). The main rate-enhancing parameter in the stripping of gold and silver is temperature. A secondary rate-enhancing parameter is ionic strength. (1) Stripping is usually conducted within a solution containing sodium cyanide (0.1 -0.5% ) and caustic ( 1 -3%). The development of a chemistry that increases the rate of gold and silver stripping from carbon in a manner proportional to its concentration is described. Its use in atmospheric and pressure strips is also outlined.

Jan 1, 1992

By G. H. Roybal, J. M. Barker

Humate mining in New Mexico is a small industry [455 m3 (16,079 cu yd) valued at $395,894 for 1983] with three mines active in 1985. Either humate (carbonaceous claystones rich in organic matter) or weathered coal ("leonardite") high in humic acid are mined. The humic acid content needed to meet consumer specifications determines which type is mined. The humate and "leonardite" now mined in New Mexico are used primarily as soil conditioners or as drilling mud additives. The potential resource for both are very extensive within the coal-bearing formations of the San Juan Basin in northwest New Mexico.

Jan 1, 1987

By John A. Wolfe

Applications of mathematical statistics to the field of exploration are still relatively new. There are two primary reasons why little has been published in this field. First, if one discovers an effective technique for exploration, he does not like to disclose it. Second, the geologist needs to work closely with a mathematical statistician, and the communications barrier between the disciplines is formidable. The authors of this paper, one a geologist and the other a statistician, were interested in the economic benefit which appeared to be possible in the interdisciplinary area which they have called "geostatistics." An actual example has been selected to illustrate this benefit.

Jan 1, 1962

By Victor F. Hollister

This first section of case histories of mineral discoveries, Vol. 3, covers some of the milestones in porphyry copper and skam exploration successes. It was during the era of these discoveries that large, complex exploration departments emerged as permanent adjuncts of large mining companies. The discoveries helped shape how and where exploration activity was conducted. Probably the most important factor in exploration success is management. Few management people are mentioned in this section or in any exploration history, yet the distinction between success and failure ultimately rested with the decisions they made. One of the most successful groups was initiated by Roger Straus and Herbert Brownell when they sought to make Asarco into an important metal producer. Relying on Clem Pollock and L.H. (Bill) Hart to identify and push worthwhile projects, the Asarco management remade the company. Asarco will benefit from exploration successes com- pounded by that team for years to come. Duval is an example of a management that decided to add metal production to its industrial minerals output. When Page Morris was president, that company opened three major porphyry copper mines and became an important factor in metals. Under the Monis management team, Duval became a leader in exploration. At the other end of the scale are managements that snatched defeat from the jaws of victory and by so doing changed the character of their companies in other ways.

Jan 1, 1991

By Wescomb R. Jones

The United States is the world's largest producer of hydrofluoric acid (HF), with its 1971 output of 317,000 short tons representing about 40 percent of the estimated Free World production. U. S. production has increased over five fold in the past 20 years, with a growth rate of about 7 percent per year between 1960 and 1970. However, the growth rate to 1977 is expected to be less than 5 percent per year, due primarily to a reduced rate of growth in requirements by the aluminum industry and an expected increase in imports from Canada and Mexico. This discussion will include our analyses of the consumption pattern for HF in 1972 and the factors influencing the demand forecast for 1977.

Jan 1, 1973

By William H. Dresher

A study has been made of the reaction mechanisms occurring during the salt-roast process to form water-soluble sodium vanadate compounds from the vanadium oxide compounds present in vanadium-bearing ores and concentrates. Two reactions have been identified, either of which lead to water-soluble compounds--oxidation of sodium chloride by water vapor and. oxidation of sodium chloride by oxygen. The former reaction has been found to be predominant in the salt-roast process. A kinetic treatment of the data has shown that for the formation of sodium metavanadate the rate-controlling step in the reaction, in which sodium chloride is oxidized by water vapor is the decomposition of a species containing water and sodiumm chloride, on the surface at the gas-solid interface. For the formation of sodium pyrovanadate, the rate-controlling step is the decomposition of a species containing water and sodium metavaradate on the surface. The transportation of water through the system, perhaps as a sodium chloride-water complex or a sodium metavanadate-water complex, and the actual chemical reaction are relatively fast compared to the initial surface decomposition step. A similar treatment on the data for the oxidation, of sodium chloride by oxygen has shown that the rate-controlling step, is the actual transportation of oxygen from the gas-solid interface to the reactive site. This transportation is by a sequence of two diffusion processes. Transportation during the early stages of the reaction is by the diffusion of oxygen through a continuous layer of reaction product. After, the first few minutes of reaction time a second diffusion process begins and is continuous for the remainder of the reaction. This second diffusion process involves the diffusion of oxygen, through a layer of reaction product that has developed voids around which the oxygen must diffuse. The hindering, nature of this latter process causes the rate of transportation of oxygen to the reaction site to be considerably slower than by the simple diffusion mechanism initially followed. A thermodynamic treatment of the data has shown that the energy of activation for the decomposition of the water-sodium chloride species on the surface is -12.1 Kcal. per mole. For the decomposition of the water-sodium metavanadate species on the surface' the energy of activation is -15.1 Kcal. per mole. The results of this study indicate the limiting mechanisms of the basic reactions occurring during the salt-roast process. These results suggest what variables should be examined in applying this information to actual plant operations.

Jan 1, 1961

Direct force measurements were conducted using an atomic force microscope (AFM) to study the mechanism of copper-activation of sphalerite. The force measurements were conducted between a sphalerite plate and a hydrophobic glass sphere in xanthate solutions of various pHs. The glass sphere may represent the hydrophobic air bubbles interacting with minerals during flotation. The force measurements conducted with unactivated sphalerite in 10') M KEX solutions did not show the presence of hydrophobic force. On the other hand, the results obtained with copper-activated sphalerite at pH 9.2 and 4.6 showed strong hydrophobic forces. However, the results obtained at pH 6.8 showed no evidence of hydrophobic force, which provides an explanation for the difficulty in floating sphalerite at neutral pH.

Jan 1, 1998

By Bernhard C. Koch, Richard W. Hutchinson, Bernhard Free

The Tertiary Silverton caldera collapsed asymmetrically to the southwest 27.5 m.y. ago. Resurgent volcanic activity is expressed by a quartz-monzonite stock at the southern caldera margin and by the Red Mountain porphyry stock in the northwest of the caldera which were emplaced at 25 m.y. and 11 m.y. b.p., respectively. The apical Eureka graben formed between 27.5-22.5 m.y. ago and transects the Silverton caldera southwestward. In the northeast it terminates at the 22.5 m.y. Lake City caldera margin. This graben as well as caldera faults provide dominant structural control for base and precious metal deposits. The epithermal gold mineralization of the Gold King mine is proximal to the Red Mountain stock in the north central part of the caldera. Here, west-northwest striking faults related to the collapse of the caldera intersect northeast faults of the Eureka graben. Superimposed upon earlier base metal mineralization at 23 to 22.5 m.y. b.p., the 11 m.y. younger gold metallization was a distinct event at Gold King. Supergene enrichment of the hypogene precious metal assemblage resulted in a metal tenor of up to 3,016 g/t gold and 1,088 g/t silver. The deposit is hosted by quartz-latite tuffs, flows, and flow breccias of the Burns Formation. Veins, up to 5 m wide follow steeply southeast and northwest dipping structures of the Eureka graben. Subsidiary veins up to 2 m wide branch off the main lode and are termed "flat veins" because of their conformable strike but shallow dip of 45' to 50' toward the northwest. Meteoric water-dominated hydrothermal solutions generated by the Red Mountain stock ascended through intensely fractured, ferruginous

Jan 1, 1988

By Joseph B. Alberts, David D. DiPonio, Francis B. Manning

From 1996 to 2001, Wayne County and 13 suburban Detroit communities constructed the Downriver Regional Storage and Transport System (DRSTS) to improve area water quality, protect public health and alleviate basement flooding. The project consisted of a 10-mile long storage and transport tunnel, a pump station at the existing wastewater treatment plant, 9 miles of relief sewers (6 in tunnel and 3 in open cut). The work was separated into 10 contracts. Due to hydraulic design requirements and other constraints, the tunnel profile was located generally 65 feet below ground surface within a soft to medium clay strata which skimmed along the top of a very dense glacial till “hardpan” overlaying bedrock. Boulders within the tunnel bore were recognized as a significant, but indeterminate risk. This paper presents a case history of the owner’s contracting strategy for risk assumption and management of the boulder impacts on the project. Actual conditions encountered during construction and contractual adjustments made to address problems are reviewed, and recommendations for future contracts are included.

Jan 1, 2003

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 P. -J. Kleiterp

Highwall mining is a mining method to extract coal from a final boundary in open cut mining, trench mining or contour mining. This boundary may have been reached because of economic constraints (economic strip limit) or geographic constraints (spoil heaps, rivers etc.). Coal is mined from visible, horizontal, or near horizontal coal seams by making rectangular, parallel, unsupported drives with an unmanned cutterhead and coal transport system. This is controlled from a mining unit, or launch frame, positioned outside the drive, in front of the highwall. Removal of overburden is not required or is limited to small quantities only. Highwall Mining originated in the 1940 in the Appalachian Coal Field. This paper describes the history of the various machines that have been designed for highwall mining. During the 1990 and later, there has been more emphasis on the safety in highwall mining. Many pillar strength formulae have been derived to determine the required width of pillars in highwall mining and, with that, the economic feasibility of highwall mining. The various pillar strength criteria will be discussed in this paper showing the countries where they are applied. In order to make highwall mining equipment safer and more productive, there have been quite some technological improvements applied to the machines. These technologies make highwall mining ready for the future as a serious mining method, also outside its traditional Appalachian mining area.

Jan 1, 2010

By P. A. Meyer

The Tenmile Range is a north trending zone of high relief within the central Colorado porphyry-mineral belt, located between Leadville and Breckenridge. (Figure 1, the Index Map of the area surveyed.) The Climax mineralized zone is located at the southern end of the range on the northwest side of the Continental Divide. This portion of the total area surveyed will be discussed in detail today. A fixed wing aeromagnetic survey was flown over this range and mineralized zone in the fall of 1957. The survey was run as an experiment to see if a useful geophysical tool could be applied in the exploration for similar type deposits. The purpose of this paper is to describe the results of this survey and the approaches used to aid in the interpretation of the total intensity data.

Jan 1, 1968

By S. B. Bhagwat

The United States has abundant coal resources that could last at least another century. and probably longer at present consumption rates. Geographically, the coal resources are distributed over the entire nation including Alaska, although there are no coal deposits in the highly populated areas on the two coasts. This allows free access to the coal, but makes transportation more expensive. Not all coals can be utilized equally because they differ vastly in quality. The sulfur content of coals, considered as the most detrimental acid rain-causing element, varies from as low as 0.3 percent in some areas of the western U.S. to 5 percent or more in parts of the Midwest. The chlorine content, which causes corrosion of plant hardware, also varies regionally. The 1990 amendments of the Clean Air Act of 1963 (CAA) require that emissions of sulfur be restricted and rolled back in two stages by the year 2000. There have been a number of reports expressing concern about the future of the industry in the states where high sulfur coal is produced. The remedies devised by the federal government and many coal-producing states in the past to "se-cure" the future of the regional coal industries have focused on the physical task of removing sulfur rather than the economic challenge of doing so at a cost that will enable high-sulfur coals to survive and compete. The past remedies, generally, were not specific enough to account for the characteristics of regional coal deposits and did not look at the coal market as an integrated national and international entity. The State of Illinois has, in recent years, taken a more comprehensive approach to the solution of the problem.

Jan 1, 1992

By G. Bonifazi

In the present work the possibility to utilize the morphometrical and morphological characteristics of an articulate solids system in a slurry flow to monitorate and to control a continuous process is considered. This goal has been reached by mean of an optical system able to acquire, to handle and to process the pictorial information derived by a suitable hardware architecture designed to realize the best lighting, focusing and sampling conditions for the examined flow stream domain. The procedure has been tested using different flow stream slurries coming from different sections of a beneficiation plant. A suitable strategy and a consequent software architecture has been set up in order to assure to the system the necessary speed and the stability to achieve correct on-line measurements and control.

Jan 1, 1994

By Robert Roggenthen

In 1994, ASARCO's Mission Complex Mine Planning Department designed a new stripping schedule to take advantage of reserve opportunities. Based upon the new stripping design, overburden removal exceeded available hauling capacity. This increased hauling capacity requirement required that ASARCO consider alternative technologies for material transport. In 1997, ASARCO Mission Complex completed the purchase and installation of a 3.5 km, 8,600-tph conveyor system to transport waste material. The conveyor system is composed of two apron feeder/sizer units manufactured by Mining Machine Development LTD. and a conveyor system manufactured by Krupp-Robbins. This paper will review the option of truck haulage versus conveyor transport for overburden removal by (1) describing engineering studies contributing to the solution, (2) researching proactive options to create alternative management decisions, and (3) revealing final results of the project.

Jan 1, 1998

By G. Kris Kapoor

Each new period of public concern, whether rooted in things political, social, economical, or technological, brings with it new words or phrases which highlight that new interest. With people's awareness of our rapid depletion of readily available energy sources and the enormous increase in energy .costs came the new, and now often heard, terms "energy intensive", "energy sensitive", and "energy conservation". Since its birth in 1926, Fuller Company had been directly associated and involved with energy intensive products and processes. We are located in the heart of the Cement Industry. Many of our products and processes are geared to the needs of the portland cement manufacturer, and a look at the inferno within an operating cement or lime kiln will certainly convince anyone that here is an energy intensive process. Fuller Company, then, has always been energy sensitive. Process kilns, hard rock crushers, tube and roller mills, fluid bed thermal reactors, pneumatic compressors and conveyors, material coolers - all are Fuller Company products utilizing or transferring large amounts of energy. Consequently, much of our success in the marketplace depends on how wisely we design and plan for efficient use of power and for conservation of each unit of heat available.

Jan 1, 1975

By Hugh Boyd

Jet pulverization is a relatively new tool for fine grinding. It is not yet in general use in the mining and ore dressing fields, since most of the requirements in these areas have been for relatively coarse particle sizes. As the need for finer grinding increases - because of different ores, new products, and new values being sought - jet pulverization will, increasingly, be properly used.

Jan 1, 1969

By Hasan Sevim

This paper summarizes recent developments in modeling of underground coal slurry haulage networks for determination of optimum design and operating parameters. The model presented here is based on a stochastic dynamic programming formulation, applicable in any typical room-and-pillar and/or longwall mining configuration commonly practiced in the United States. The formulation and the structure of the model is general enough to handle design problems involving more than one face and mining method. Given the stochastic operating characteristics and a system layout, the model can be used to determine the equipment configuration and operating regimes that minimize the overall unit cost of coal haulage.

Jan 1, 1983