Search Documents

By Donald Towse

The Permanente plant of Kaiser Cement & Gypsum Corporation is located at a unique thick deposit of Calera Limestone (Figure 1) on the southwest side of San Francisco Bay. Limestone is rare in the eugeosynclinal Franciscan assemblage, constituting less than 0.1 percent of the total volume. On the northwest part of the San Francisco peninsula Calera Limestone is present as isolated masses from the type sect ion near Rockaway Beach southeastward for ten miles, where the belt is truncated by the San Andreas fault. The large Permanente deposit is sixteen miles south of the truncated belt, on the northeast side of the San Andreas fault. Scattered small exposures are known for about twenty miles southeasterly from Permanente. (1,2) Most deposits of Calera are thin; the type section is about two hundred feet thick. At Permanente, however, the normal limestone section contains at least four hundred feet of limestone; and, due to folding and extensive faulting, the total vertical thickness of the limestone section is over 1400 feet. The unusual thickness of limestone is due to low angle thrust faulting. This fortuitous structure formed a deposit of limestone that supplies an 8,500,000 barrel cement plant in a major metropolitan market.

Jan 1, 1966

By Frank H. Skelding

A new, large mine is about to be born. Many years and millions of dollars have been invested in exploration. An orebody has been found and proven. All necessary political and legal work to establish rights and conditions for development are complete. The feasibility studies are favorable. Financing has been arranged. Board approval has been given to proceed. The time has come to engage a contractor to design and build the new facilities in a location, as is the common case today, far re¬moved from the centers of advanced technologic development where the minerals will ultimately be used. A select list of Engineering and Construction (E&C) companies is asked to prepare proposals. At this point the common viewpoint among mining companies is that the company's sole remaining problem, a major one to be sure, is to select qualified contractors to design and build the project at the lowest cost and shortest time possible so that production can start generating a return on investment. The purpose of this discussion is to explore the viewpoint of the large E&C contractor toward such projects. It differs in important ways from that of the client mining company and it is these differences and the reasons for them that must be understood by the client if severe difficulties and misunderstandings with the contractor, starting at the beginning of contract negotiation and continuing through design and construction to final startup are to be avoided or minimized. Often enough, the difference is in degree, not kind, which only serves to obscure the fact that a difference exists.

Jan 1, 1975

By Arthur S. Radtke

The structural setting of disseminated-replacement gold deposits of the Carlin-type and other aspects of their genesis are closely related to events which took place during the evolution of the Basin and Range province. The deposits formed as a result. of chemical and physical processes which took place at shallow depths in the roots of hot spring systems at moderate temperatures (about 200°C) and low pressures (about 25 bars) (Radtke and Dickson, 1974). Locations of Carlin-type gold deposits in the Basin and Range province are shown in Figure 1. Most of the block-faulted mountain ranges in the Great Basin formed by tectonic activity that happened since Miocene time, although faulting in some places probably began in Eocene to Oligocene time (Hamilton and Myers, 1966). The Carlin-type deposits are spatially related to Basin and Range-type faults: Many deposits, such as Getchell, Pinson, Preble, and Cortez, occur along the flanks of ranges, while other deposits, including Carlin (Radtke, 1974) occur within the ranges in areas characterized by crosscutting and intersecting high-angle or Basin and Range-type faults. The association of the ore deposits with Basin and Range-type faults is evidence that ore deposition is young, Miocene or later. The steep, high-angle faults played three roles: first, they provided deep channels for upward-flowing solutions; second, in preparing the rocks for fluid penetration by brecciation and general rock dislocation; and third, they moved sedimentary carbonate rocks, favorable for ore deposition, from deep levels to near-surface positions where the physico-chemical conditions were more suitable for the deposition of ore.

Jan 1, 1976

By Legett Garrett

Texas Utilities Generating Company (TUGCo) surface mines lignite for use as a boiler fuel at mine mouth generation stations. Currently, the annual lignite production requirement of approximately 28 million tons necessitates mining across approximately 1,600 surface acres each year. The mining operations, located in Freestone, Panola, Titus, and Hopkins counties, Texas, have drastically disturbed some 13,000 surface acres to depths of up to 110 feet since initial startup in 1971. The TUGCo mining philosophy, a commitment made prior to initiation of mining operations and prior to any mining regulations, includes a return of mined-out land to private ownership in the most useful state possible. In the areas of TUGCo operations, the local economies are based upon agricultural production. Historic land use surveys have typically shown a trend from row crop production to pastureland for cattle production. During the 1960?s, the percentage of acreage devoted to row crop production approached zero with respect to the total acreage devoted to agriculture. TUGCo reclamation operations have therefore emphasized restoration of land to a state that is favorable to cattle production

Jan 1, 1982

By C. N. Bailey

Let's review the economic factors in mill design. Talking about engineering economics in mill design reminds me of an old' saying "There are several ways to handle women but nobody knows what they are." I'm sure that the same economic factors do not apply to each of our mill designs, but for the sake of emphasis, it is well to review a few of them. They are so simple that we are apt to feel they are not important. Other speakers today are talking about the engineering factors of mill design, but I'm asking the question "Have we checked the economic factors involved in these designs? Have we checked the obvious? Many great discoveries have resulted from analysis of the things that appeared to be obvious all the time. What are some of these economic factors? Perhaps the most basic one is simply the value of minerals in place if minerals have value in the ground, they have value only because many important and different considerations add up to the probability that the minerals can be mined, beneficiated and disposed of profitably. The size formation and quality of the ore body, the distance from market, and the transportation available to the market area, depreciation rates, taxes, and the ownership interests involved are but some of the factors that must dovetail into the answer of profit, an answer prerequisite to hoped-for financing.

Jan 1, 1961

By Jess W. Smith

The carbonaceous Monkemeyer sandstone member of the Creede Formation on Bachelor Mountain hosts alteration and mineralization which contrasts with other silver deposits of the Amethyst system. More than 20 million ounces of silver are contained in disseminated mineralization in the volcaniclastic conglomerates and sandstones. Hydrothermal fluids entered the Creede Formation directly from the Amethyst fault system and mixed with flowing meteoric ground waters trapped beneath the Monkemeyer sandstone. Portions of the basal rocks of the Creede Formation were argillically altered by more dense acidic fluids generated by boiling. The carbonaceous base of the Monkemeyer and much of the conglomerates below were mineralized and well silicified. Deposition of the mineralization resulted from two processes: (1) reduction by carbon in the Monkemeyer, and (2) fluid mixing in the conglomerates. Monkemeyer mineralization is confined to the carbonaceous basal material and silver content is relatively consistent. Silver is contained in acanthite which is commonly associated with traces of galena, chalcocite, covellite and sphalerite. Fluid mixing and mineral deposition in the poorly sorted conglomerates was controlled by the highly variable porosity and permeability. Anomalous silver contents are dispersed throughout a large volume of conglomerates but zones of higher silver content reflect the crude layering of the conglomerates. Acanthite is finely disseminated in pore spaces and partly replaces some detrital magnetite. other metallic minerals are rare in the main zone of mineralization.

Jan 1, 2013

By Thomas E. Howard

Engineers today face a tremendous challenge. Growing population and rising standards of living all over the world are creating unprecedented and accelerating demands on and for all kinds of technology. At the same time, the public is becoming more and more conscious of--and concerned with--the impact of technology on human welfare. The growing controversy over the Supersonic Transport is a case in point, It is clear that the modern engineer must expect to spend a growing share of his time considering this dilemma and evaluating the tools that are available to him, not only with respect to their adequacy for the job at hand but also their capability for meeting the increasingly demanding--and, in many cases, conflicting--requirements of the future. This meeting seems a particularly appropriate place to speculate about the future of mining technology. The summary of the state-of-the-art in surface mining contained in the papers scheduled for the International Conference, together with the recently published Surface Mining volume, constitute not only a major contribution to the technical literature but also form an impressive record of technologic progress. That record, and the advanced technology displayed in the exhibits, and to be discussed in the SME technical sessions demonstrate engineering achievement in which the mining community can justly take pride.

Jan 1, 1968

By Paul E. Epstein

Despite the controversies that have surrounded asbestos over the past 20 to 30 years, no knowledgeable authority has doubted the usefulness of this material. Were it not for the health risks associated with the manufacture and use of asbestos products, its physical and chemical characteristics would continue to be hailed as an undeniable boon to mankind. However, it has become clear over the past 30 years that like other major contributors to our modern industrialized society, asbestos must be handled responsibly and with the full understanding that lack of care can lead to injury, suffering and death. In this sense, asbestos shares characteristics with nuclear power, pesticides and even motor vehicle usage. It is unlikely that modern society would be willing to walk away from the benefits bestowed by any of these valuable resources. Rather, the appropriate response to the identification of danger is to define the type of risk, quantify its incidence, search for methods of decreasing the risk and implement programs to achieve the goal of minimization of risk. We should recognize at the outset that the risk cannot be diminished to zero without elimination of the material entirely from our midst. The concept of acceptable risk is a complex issue involving medical, legal, financial, moral and even psychological factors that defy precise quantification. In essence, the major danger produced by exposure to asbestos is its potential effects on the respiratory system. Despite the fact that asbestos workers have constant skin contact with the material and porbably swallow it in the course of their activities, inhalation of the fibers is recognized as the major health risk associated with its use. Aerosols of asbestos are inhaled not only by miners, millers and fabricators but also by urban dwellers who have no direct occupational contact with the material. This occurs because asbestos has been applied to our buildings and has been used in a wide variety of products that touch our daily lives. While it is estimated that three to four million people in the United States have been occupationally exposed to asbestos, the number who have been non-occupationally exposed is many times that number.

Jan 1, 1984

By James M. Baylor

Ladies and geltlemen, it is indeed a privilege and a pleasure to be here in Denver with you. I want you to know too I'm not a stranger out here. Golden, Colorado is the headquarters of A. T. Massey Coal Company's Western Division, headed by Vice President, Gregory H. Hoyl. I also have a very close friend and fraternity brother who works and lives in Denver so I could talk on and on about this area and our western coal properties, but it's Massey's coal terminal business I'm to focus in on today, and that's a horse of a different color. So on to the subject of my address: MASSEY COAL TERMINAL INVOLVEMENT As I have stated on other occasions, A. T. Massey Coal Company, for better or for worse, is in the coal terminal business.

Jan 1, 1981

By Henry P. Ehrlinger

These are exciting times for those of us involved in the discovery, development, beneficiation, sales and end uses of industrial minerals. The known sources of traditional raw materials are rapidly being consumed or covered up with highways and urban developments. We would never knowingly cover up a source of gold, silver, diamonds, or even base metals with a shopping center, but it has been difficult to justify not locating construction atop a limestone, granite, or sand dune deposit. During the last ten or so years most of the users of significant amounts of industrial minerals have established task forces made up of geologists, mining engineers, beneficiation experts, ceramic and refractory scientists, and senior members of their purchasing departments whose duty it is to determine where the raw materials for their particular finished products will come from now and farther down the road, like 20 years from now. Likewise, these same ceramic and refractory scientists are developing new materials which require a never ending change into different raw materials and the traditional materials must be refined by selective mining, exotic beneficiation practices and expensive but necessary post-beneficiation treatments to produce minerals for commercial use that were either theoretical minerals or at best showcase specimens when most of us here today were in school studiously acquiring a vocabulary which included Calcite, Magnesite, Dolomite , Feldspar, (Labradorite had the play of colors the prof could see but which I rarely focused on) Wollastonite, Celestite, Chromite, Olivine, Barite and Lepidolite to name a few.

Jan 1, 1976

By R. C. Runvick

Gypsum resources are significant in the midwestern United States, with specific deposits varying in "place value" relative to the major markets served. Underground and surface mining operations produce gypsum from sedimentary rocks ranging in age from Silurian through. Jurassic. Although reserves tend to be limited at individual operating properties, potential resources are vast and future development will hinge principally on market growth and changing economic conditions. Most critical of the variables affecting the industry in both the short and long term will be the availability, type and cost of energy and both processing and distribution.

Jan 1, 1980

By V. E. Cole

For the successful execution of a major project, the project team must be thoughtfully organized, manned, instructed and motivated. This is true of both the engineer/constructor team and the mining company team. Then these teams must be carefully related so that they function effectively as one organization on the job. This paper describes the organizing techniques and the human ingredients and know-how of a successful project.

Jan 1, 1980

By Allison L. Hornbaker

Millions of years ago, in late Cretaceous time before man existed on Earth, tremendous orogenic forces began to change the face of the western part of the North American Continent. Catastrophic events marked by huge uplifts of thousands of square miles in the Cordilleran Belt, some of which are barely discernible in the geologic record, were accompanied by long periods of batholithic intrusions and volcanic eruptions. These events produced the great Rocky Mountain systems, which were at the time even higher and more rugged than they are today. Such activity continued into Tertiary time, and during the Pliocene and Pleistocene periods millions of tons of volcanic ash were hurled skyward by explosive volcanic activity and carried by the westerly winds to the east where it settled out of the atmosphere and deposited over thousands of square miles of the high plains. Unusually heavy rains, probably caused in part by the volcanic activity itself, together with high winds, reworked and redeposited the freshly fallen ash into lakes and depressions of varying sizes and shapes. Subsequent deposits of sand, gravel and loess covered the deposits of volcanic ash, preserving them in the condition in which they are found today. In many places erosion has cut through the sand, gravel, loess, and volcanic ash so that in favorable localities on hillsides and gullies, exposures of volcanic ash can be seen interbedded with sand and gravel.

Jan 1, 1970

By J. R. Knudson

A major contribution to the art of blasting was made at the Cleveland- Cliffs Iron Company?s Hawkins Mine in Cashwauk, Minnesota during April of 1956. It was here that the first experiments with fertilizer grade ammonium nitrate were conducted-experiments which led to the development of the ammonium nitrate and fuel oil method of blasting which has been eagerly adopted by open pit and quarry operators throughout the United States. While this new blasting agent was a more or less natural outgrowth of the Akremite Process devised by Maumee Colleries of Terre Haute, Indiana; no one, to our knowledge, had used this particular combination of ingredients prior to this time. Certainly this was a "break-through" as far as the Lake Superior District was concerned. Akremite consists of a mechanical mixture of grained ammonium nitrate and a solid carbonaceous material packed in a plastic bag. At the time of its introduction to the Mesaba Range, Akremite sold for 10.5 cents a pound as compared to the 18 cent powder previously used in both wet and dry large hole blasting. The discovery of this agent was indeed a remarkable achievement, one that afforded a substantial reduction in blasting costs. However, Akremite proved to be only an intermediate step in the evolution of our present low cost explosives. Cleveland-Cliffs utilized prilled ammonium nitrate and fuel oil and then eliminated the mixing and packaging plant entirely by combining the two raw materials in the field at the drill hole collar or in the hole itself. Thus we have approached the ultimate in simplicity, for the blaster and his helper now manufacture their own explosives not only as they are needed but where they are needed, and at a cost of under 4 cents a pound. This two-man crew may charge and explode as much as 8 tons of ammonium nitrate in an eight-hour shift and in so doing break some 65,000 tons of ore.

Jan 1, 1959

By Don Muraoka

Soda ash, anhydrous sodium carbonate, is produced from underground trona deposits occurring in the Green River Sasin of Southwestern Wyoming. Stauffer Chemical Company of Wyoming, a jointly owned subsidiary of Stauffer Chemical Company and Rocky Mountain Energy Company mines the trona and processes it into high-purity soda ash. Stauffer Wyoming has been in operation since 1962 with a current production capacity of approximately 2.2 million tonnes (2 million short tons) per year of soda ash. The Refinery has five parallel operating trains utilizing the monohydrate process which is a series of chemical processing unit operations described below. Screening and Crushing the Trona The mined trona is brought to the surface in two counterbalancing ore skips. The ore is initially screened with Refinery feed, less than peagravel size material, entering the process while the oversize is conveyed to an outdoor stockpile.

Jan 1, 1984

By William W. Shriver

When the Henderson Project is completed in 1975, it will become one of the Free World's largest primary molybdenum producers. The Henderson Mine will be located approximately 50 miles west of Denver, Colorado, on the eastern slope of the Continental Divide. Ore reserves are currently estimated to be 303,000,000 tons with a grade of 0.49% MoS2. The mill and tailing area will be located approximately 14.5 miles from the mine in the Williams Fork Valley, which is on the western slope of the Continental Divide. Ore haulage from the mine to the mill will be by ten miles of underground railroad and 4.5 miles of surface railroad. The concentrator has been designed to mill 30,000 tons per day and will yield approximately 50,000,000 pounds of contained molybdenum per year. This paper is concerned with the tailing and water supply system for the Henderson Project and in particular the environmental considerations affecting their design.

Jan 1, 1970

By Homer S. Anderson

To clarify what r mean about this long title, I would like to define the term technology. A standard definition of the word "technology" is "a technical method of achieving a practical purpose". Incidently, another definition of the term is merely "technical language". The same dictionary defines the word "technology" as "having a special, usually practical, knowledge of mechanical or scientific subject." Naturally, the practical purpose of the subject with which we are concerned is solving of problems we encounter in the mining industry. I might further describe the subject of this discourse by defining the term "manager". An old definition, "one who dispenses the duties of his position with care and economy." In line with the above definition most of the technology with which we in the mining industry are confronted with deals with some form of cost reduction. This may be related to the speed of doing an operation or to saving of labor or supply costs. These can be improvements of an existing method or the result of new processes or inventions, such as new machinery.

Jan 1, 1974

By Ronald L. Haxby

This report presents a refractive seismic technique for evaluating the strength of rock within an open pit bench. A concept of correlating rock strength and seismic velocity is discussed and a method of predicting the degree of fragmentation of a pit bench is introduced, Figure 1 shows the area of interests [ ] Most of the work was performed while completing graduate studies at the University of Arizona.

Jan 1, 1967

By G. M. (Frits) Swinkels

The Apex property, mined in the early Twentieth Century for direct shipping copper, also contains gallium and germanium in iron oxide minerals. In 1982, Musto Explorations Limited began an exploration program to define reserves. A metallurgical process was developed, and a production decision was reached in late 1983. This text describes the process development and design. The Apex mine, located near St. George in Southwestern Utah is owned by St. George Mining Corporation, a subsidiary of Musto Explorations of Vancouver, B.C. Musto acquired the property in early 1982. A pilot plant was operated by Hazen Research, Inc., Golden, CO later in 1982. In late 1983 sufficient information had been developed for St. George to proceed with the project. The final process design was prepared by G. M. Swinkels of Vancouver, consultant to Musto, and Hazen Research. Process engineering was done by Hazen Research, and St. George acted as its own contractor. Commissioning of the plant began in October 1985.

Jan 1, 1986

By J. D. Forrester

I have availed myself of the opportunity to prepare, and to give this talk because, as incumbent Chairman, I am directed by the Bylaws of the Council of Education to make an Annual Report of the Council activities which have transpired during the past year. In addition, and inasmuch as I have this captive audience, I am taking the liberty to express also some beliefs I hold about various other elements of Mineral Industry education. First, my report is that constructive progress has been achieved in the Council of Education during 1960-61. These advancements have been particularly notable through projects carried on by the Committee on Meetings and Programs, by the Student Chapters Committee, by the Accrediting Affairs Committee and by the Committee for Securing Better Representation of Mineral Industry Colleges. I believe each of these groups will report concerning details of their respective programs at the Business Meeting of the Council. On the other hand, not as much has been done in some areas of work as I had hoped would be the case when I took office as Chairman last February. Let me make clear that these delinquencies, for the most part, have resulted through my ineptness in handling of affairs; they are not caused by the failure to perform various assignments which I have given to council members.

Jan 1, 1961