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By Donald Towse

Portland cement is a basic building material in every country in the world, and, fortunately, the raw materials required in its manufacture are widely distributed. It is a low-priced bulk commodity (price one cent a pound or less, with a density of 100 pounds per cubic foot.) Table 1. Approximate price per pound of selected mineral products. Copper 48 cents per pound Aluminum 27 Lead and zinc 15 Asbestos 3 to 18 Pumice 6 Sulfur 2 Bauxite (abrasive) 1.8 Barite 1 to 1.6 Cement 1 Primitive regions may get along without any Portland cement, but most countries use some, and it is one of the most widespread building materials, even if used in small quantities. Use of cement begins early in a country's development, and, because of local availability of raw materials, cement manufacture is one of the first heavy industries many countries desire. Use and manufacture of cement usually precedes other industrial materials such as steel and heavy chemicals, and consumption levels off for a long period during development of infrastructure and an economic base. With a mature economy comes a very high consumption. Per capita consumption varies ten times or more between nations (Figure 1).

Jan 1, 1970

By Richard F. Roethe

Surface coal mining productivity in the U.S. and Illinois has shown a general declining trend since 1969. The U.S. Department of Energy conducted an analysis in 1980 of the causes of declining productivity in different states. This paper presents a detailed analysis of changes in overall productivity and productivity in different functions such as overburden preparation, overburden stripping, reclamation, coal handling, etc. during the period 1970-1982. Statistical analysys techniques including multiple regression were utilized in the study.

Jan 1, 1983

By H. Habenicht

Requirements for full extraction in underground coal mining call for inexpensive, safe, techniques to be competitive with conventional methods. Longwall and shortwall systems are to some extent employed for this purpose. Another method would be rib pillar extraction (and pillar extraction). These methods are compared with each other with respect to procedure, equipment, safety, roof control, investment, output, performance, costs The advantages of r.p.e. show this method very attractive. Number and cost of equipment are lowest. Safety and roof control becomes improved by a mobile roof support recently developed in Austria. Its successful use in the R.S.A. is being explained.

Jan 1, 1986

By R. J. Morlock

Prior to 1912, coal research for Republic Steel, Corporation was limited to a periodic box test conducted in a commercial coke oven. Then in 1912, a Koppers movable-wall test oven was -built to research wall pressures for selected blends and to conduct other varied research work. In the 1950's economic pressures caused a reassessment of position resulting in the establishment of a Coal and Coal Chemical research group in 1956. In 1958 this group, along with other groups of research endeavor were incorporated into the new Republic Steel Corporation Research Center at Independence¬ Ohio. Currently this section is divided into four groups. 1) Coal Preparation, 2) Coal-Chemicals, 3) Coal Characterization, and 4) Coal Carbonization. The objective of each group is described, and a brief listing of the work done under the first three groups is indicated. A more detailed description of the studies by the Coal Carbonization group of the coking characteristics of Republic Steel Corporation's coals as blended among themselves or in conjunction with selected purchased coals follows. The wall pressure, contraction, and stability index criteria are specified, and the method of assessing these criteria as a function of blend composition is indicated.

Jan 1, 1963

By William L. Jude

INTRODUCTION Although the mining method described in this chapter is locally designated "modified Mitchell," there are so many features which are characteristic of square sets that the designation "modified square set" would describe the method equally well. The method was developed as a result of local operating experience with various mining methods, observing operations in mines in the southwest where Mitchell stoping had been thoroughly developed, and an exhaustive study of min¬ing methods literature. Since 1941, modified Mitchell stopes have con¬tributed over 50% of the total stope production and were largely responsible for supporting production dur¬ing the war years and period of declining manpower and increasing costs. GEOLOGY The community of Gilman is situated on Battle Mountain at an elevation of 2743 m (9000 ft) in the Battle Mountain mining district, about 45 km (28 miles) by highway north of Leadville, CO. The sur¬rounding area, including the Mount of the Holy Cross and Eagle River Canyon, is noted for its beauty and recreational facilities, both summer and winter. Massive sulfide ore bodies of the limestone replace¬ment type occur as chimneys and mantas or as blankets in strata dipping 0.19 rad (11°) northeasterly. A chimney is shaped like an inverted cone with shale, quartzite, and porphyry caprocks forming its base. This relatively impervious capping apparently blocked rising ore constituents which formed the chimneys and mantas. At the apex or lower extremity of the chimneys, the ore follows small fractures and bedding planes in under¬lying quartzite. Dimensions of chimneys vary, ranging up to 61 m (200 ft) vertically and 76 m (250 ft) horizontally near capping. The manta or blanket ore bodies vary in vertical cross section from one hundred to several thousand feet. One such manta was developed from its outcrop to its chimney source approximately 610 m (2000 ft) downdip. Another manta of substantial cross section and length did not follow shale but extended updip with limestone capping from its source at a lower horizon. All chimneys, however, make up to the shale¬quartzite-porphyry capping. Chimney ore minerals are mainly pyrite and chalco¬pyrite with accessory copper and silver minerals, surrounded by, and in places overlain with, marmatite, pyrite, and galena. Manganosiderite extends into the ore. It may or may not be impregnated with sufficient marmatite and galena to be of commercial grade. Ore may be massive, coarsely crystalline, or sandy, some¬times rubbly. Generally speaking, chimney ore masses are incompetent and of variable grade. Caprock is heavy and caves readily. Manta ore minerals are mostly marmatite, pyrite, and galena associated with manganosiderite. Structural characteristics of the ore are similar to those found in chimneys and where the manta contact shale capping the ground is unusually heavy. However, the large manta with limestone capping mentioned previously consisted of a hard strong ore mass in fairly strong host rock. Commercial ore contacts are fairly regular in this manta but in others the ore waste contacts along the walls are irregular with shaly limestone pendants extend¬ing downward into the ore at capping. Dolomite sand is also quite frequently encountered along wall contacts and less frequently overhead. MINING METHODS Practically all stoping in the Gilman ore bodies has been carried on with timber and fill methods and the features which have been briefly described have dictated the choice. Although at the present time modified Mitchell and underhand square-set stopes account for the total production, considerable production has been obtained from alternate horizontal cut-and-fill stopes with Mitchell truss stopes in the pillars. This method was highly satisfactory in the hard manta ore body mentioned earlier and where ore excavations 11 m (35 ft) wide and 23 m (75 ft) long required no auxiliary timber support. It was a pillar recovery application of the method devised by M. W. Mitchell at the Calumet

Jan 1, 1982

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By J. E. Lonergan

The in-pit placement of crushing and conveying equipment results in a flattening of the pit slope of a multiple-bench open pit mine. To maximize the economic benefit of lower haulage costs associated with in-pit conveying, one must minimize the cost of the flatter slope which is expressed in terms of additional stripping or tied up ore. A computer program that compares the tonnage aspects of various conveyor layouts will be discussed.

Jan 1, 1985

By L. R. Hossner

Chemical and physical properties of surface soils and overburden materials must be evaluated prior to strip mining activities. This information can be used to assess whether subsurface overburden can be equal in quality to the existing surface soils, especially when these soils are classed as prime farm lands. In Texas, materials from the Carrizo, Calvert Bluff, Simsboro, and Hooper Formations overlie the lignite. The Carrizo Formation consists of thick clean sands with poor water and nutrient retention capabilities. These materials are least suited for placement of the surface of reclaimed land. The oxidized, medium textured overburden from the Calvert Bluff and Simsboro Formations possess adequate water and nutrient properties and are better suited for sustained plant growth. Non-oxidized Calvert Bluff and Hooper sediments generally have acceptable properties for reclamation. However, caution must be exercised in vegetating these materials since they may contain acid forming sulfide minerals.

Jan 1, 1982

By S. W. Mao

Hydrologic and economic criteria figure in many obvious ways in water resources development, but they are rarely linked quantitatively, and most of the applications are pertinent only to the case-in-point. In the preparation of the Regional Plan for the massive program of ground water development in the Punjab, situations have arisen where the choice among two or more alternatives was made by analyzing the economic implications of critical hydrologic parameters. Two of these situations which are of more-or-less general interest are described herein. The first involves basic development policy -- whether ground water development should be based on the demand of the economy, or the conservation concept of safe-yield. The analysis demonstrated that mining of ground water is clearly indicated for areas where alternative supplies are unavailable. The second problem involves integrating hydrologic data into an economic model to determine optimum well design, From an analysis of all pertinent factors, a simple nomograph was derived which can be used to determine well specifications on-site during construction. The nomograph can be modified for use in any alluvial terrain.

Jan 1, 1967

By Rodney R. Krause

In attempting to tell the general public about the coal industry's land reclamation efforts, we have often said, "We're not doing things by the book, because we're still writing it." Like any good catchphrase, the statement is not only striking but true. It is particularly true in the mountains of Appalachia, where the problems of mining; and of reclamation are made more intense by the nature of the terrain. Mining and reclaiming the land "by the book' --which is to say by the methods of contour mining traditionally used in hill country--hasn't worked too well. So a lot of conscientious coal operators and associations are trying new methods--new ways of mining, new machines for seeding and planting, and new species to seed. Not all their experience can be transplanted to other areas, and of course I don't believe that Appalachia is the only place where new methods are being developed. Nevertheless, there's enough action in Appalachia to make a detailed examination rewarding, so let's focus on the hills to see what's new.

Jan 1, 1970

By A. Z. Dimitroff

Immediate detection of methane buildup or of sudden liberation of large quantities of methane in the face area is essential to avert disasters in coal mines. Proper timely detection and handling of methane have always presented problems in extremely gassy mines, and these problems have been magnified by present accelerated mining methods. Strict rules and regulations have been established by coal-mining companies, States, and the Federal Government, which provide for periodic inspections for methane in face areas when electrical equipment is working. Other provisions require the operator' to shut down electrical face equipment and change or adjust ventilation when more than 1.0 percent of methane is detected. Nevertheless, human failure to detect such conditions has been responsible for numerous ignitions arid explosions Recognizing this fact, Marling J. Ankeny, former Director of the Bureau of Mines, proposed in 1958 the development of an automatic methane-monitoring device. He envisioned such a device as being entirely dependable, capable of giving a warning when a predetermined concentration of methane in air is reached, and capable of deenergizing the equipment and rendering it inoperative when a dangerous concentration of methane is present in the air. Such a device has been developed by the Bureau of Mines Health and Safety Research and Testing Center in Pittsburgh, Pa.

Jan 1, 1967

By Joseph M. Chelini

Today, the two major operating costs of rubber tired off-road equipment are diesel fuel and tires. Mine Management has minimal control over the ever accelerating diesel fuel costs. However, they can exercise control over abnormal tire costs. Fortunately, with available technology and cost analysis methods, experience shows us the outlook for controlling tire costs is encouraging. Most earthmoving operations using off-road, rubber tired haulage and support equipment have abnormally high total tire costs. These costs, utilizing Tire Information Management, have been reduced more than 30%; 20% can often be guaranteed. Management Apathy on the subject of tires in a complex mining operation perhaps can be understood, but management apathy applied to an abnormally high operating cost, of which tires are, begs for a solution.' Tires have been professionally neglected for many years in most mine operations. This is exemplified in the January, 1982 issue of Mining Engineering by Charlie Son in his article Reducing Earthmoving Tire Costs. He compared the efforts to improve diesel engine costs to the same efforts given to earthmover tires.

Jan 1, 1983

By P. Rusin

Many oxide silver and molybdenum deposits remain undeveloped because chemical extraction yields poor recoveries or is environ-mentally unacceptable. Bio-reductive leaching of such ore samples at MBX resulted in high recoveries of silver and molybdenum. When baseline 3-day cyanide bottle roll tests were conducted on manganiferous oxide silver ore, 13.7% of the silver was extracted. In contrast, 86% of the silver was microbially solubilized into the organic growth medium by bio-reduction with 99.8% dissolution of manganese. A follow-up cyanide bottle roll test yielded an additional 8.5% silver recovery for a total recovery of 94.5%. Baseline 3-day acid bottle roll tests of the iron oxide molybdenum ore yielded 1.8% moly. However, bio-reduction solubilized 93.3% of the moly into the growth medium. An additional 0.3% moly was recovered during the follow-up acid bottle roll test. Microbial treatment of refractory oxide ores with bio-reductive bacteria resulted in higher recoveries of silver and molybdenum than conventional chemical leaching. The bioleaching process occurred at a near-neutral pH at ambient temperatures. The bacterial solubilization of silver and moly was achieved without the use of cyanide or sulfuric acid.

Jan 1, 1992

By G. M. Smith

Several significant past and present producers of high grade and bulk tonnage gold ore from southeastern California and southwestern Arizona can be empirically and genetically linked to regional peraluminous magmatism which occurred during the late Cretaceous and early Tertiary. Geological relationships and geochemical characteristics from the Fortuna Mine area will be described and compared to those of the Tumco Mines area. Each of these historical gold producers is viewed as a morphologic end member in otherwise genetically linked metallogeny. Cold-quartz veins at Fortuna can be directly linked to peraluminous pegmatites both physically and mineralogically. Silica-magnetite±spidote±garnet rock which occurs as relatively barren, discontinuous, foliation- parallel horizons at Fortuna, but as high grade gold ore at Tumco, is interpreted as replacement of calcareous units during the same episode of peraluminous magnatism responsible for the gold vein mineralization. Whole rock and trace element data from pagmatites and aplites of the Fortuna and Tumco areas, together with data from the Gunnery Range batholith of southwestern Arizona, indicate that the magma series (after Keith, 1984) responsible for the gold metallogeny is peraluminous calcic, and is quite rich in sodium.

Jan 1, 1987

By S. B. Keith

Cerro de Pasco Corporation operates five large base metal mines in Peru having a combined production of some three million tons of ore a year. An integrated complex of concentrators, smelters and refineries produces annually about 25,600 short tons of copper, 48,100 short tons of lead, 60,500 short tons of zinc metal, 102,300 short tons of zinc concentrate, 8,272,000 ounces of silver and substantial amounts of bismuth, cadmium and selenium. Geology plays an important role in these operations. The organization of detail geologic work in and around the Cerro mines was set up by John M. Boutwell in 1918 and a geology department was established in 1920. Growing through the years, the department technical staff now numbers over thirty men and. their work covers all phases of geological investigations. Many outstanding geologists of the past and present, too numerous to name here, have studied and contributed to the knowledge of the deposits and the ever growing list of Cerro "alumni" must rival that of any other mining organization. Numerous papers on the geology of Cerro's mines can be found in the technical literature and several doctoral theses have been presented on Cerro subjects as indicated in the attached bibliography, Specimens of Cerro's ores can be found in museum, college and university collections throughout the world. Yet, as with all mines and mining districts, the geologic knowledge of Cerro's deposits in Peru is being revised and added to constantly. This presentation cannot hope to cover adequately all the phases of the geology and mineralization. For a more complete background and discussion of the mine you are referred to the bibliography. Here I shall outline only briefly the more important geologic features and describe some of the newer developments of recent years The credit for the data presented here belongs to the many geologists who have worked or are now working for Cerro de Pasco Corporation, but I must assume sole responsibility for any omissions or variations in the interpretation of their work.

Jan 1, 1965

By S. R. Dindarloo

"Truck-shovel systems are the dominant material loading and haulage machinery in open pit mining operations. Optimal selection, sizing, and allocation of this capital intensive equipment is highly desirable for both achieving production targets and improving the mine’s economics. In this study, discrete event simulation technique was applied for modeling material transportation in Golegohar open pit iron ore mine in Iran. Direct observation of the material loading and haulage for duration of three months resulted in statistical modeling of the operation in the form of probability distribution functions. These probability models were used as the inputs of a stochastic simulation model constructed in GPSS/H simulation language. The model was validated through comparison with the actual operation and was used to test different what-if scenarios and sensitivity analysis of the current system. Some modifications in the number of trucks, shovels, and dispatching strategies were proposed. Simulation resulted in considerable improvements in the mine’s production and economics.INTRODUCTION There are three different mechanisms of discrete, continues, and hybrid material transportation in open mines, including but not limited to: i) in-pit crusher and conveyor belts (hybrid), ii) slurry piping (continues) and iii) truck-shovel system (discrete). Although, each mechanism has its advantages, the truck-shovel system is the dominant method of material loading and handling in open pit mines owing to its high production rate, excellent flexibility, relatively low operating and capital costs, and good maintainability. General objectives of optimal equipment selection include: i) meeting the long and short term requirements of production rates, ii) human & equipment safety, iii) environmental protection, and iv) economic operations (Figure 1).The two most important decision factors on a truck-shovel system selection and sizing are the equipment geometry and size. Geometry (equipment width, weight, turning radius, swing angle, etc.) is mostly controlled by mine’s designs and layouts, as well, as operational constraints. After selection of a favorable geometry based on the constraints; the next step is to select the equipment manufacturer. Once the geometry and manufacturers are selected; the next step is to decide on models (e.g. Bucket size) and required number of each unit"

Jan 1, 2015

By Werner Wenzel

Methods to increase the gas penetration through sinter layers. In the field of agglomeration, sintering has gained importance, specially in Europe; in Best-Europe this trend will continue till the year 1980, since it is quite probable that in the blast furnace burdens with 50-60 sinter, 10-20 % pellets and 20-25 % ore lumps will be employed. In order to meet this demand for sinter, new sinter bands with reaction areas between 300-400 m2 will be constructed. Chemical and physical phenomena during the Suction-Draught-sinter process. Iron ore sintering is generally considered as a burning process where the material contains 90-95 % ash i.e. non-combustible ingredients. Sintering represents a heterogeneous exothermic reaction in which the chemical phenomena as combustion, calcination, hydration, reduction and oxydation are superposed by physical phenomena. The physical phenomena are devided into material transport and simultaniously occurring heat transport processes. The velocity of these combined physico-chemical reactions i.e. the change in the reaction site per unit time determine the efficiency of the sinter process. The gas permeability as an important criterion of heat transport during the Suction-Draught sinter process.

Jan 1, 1971

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"There are three distinct producing iron ranges in Minnesota, the Vermilion, Mesabi and Cuyuna. In trend the Vermilion and Mesabi are approximately parallel (E.N.E. and W.S.W.) and about fifteen to twenty miles apart. The Vermilion lies farthest north, near the. Canadian boundary. It is from seventy-five to eighty miles due north of Duluth. The length of its productive part is about twenty miles.The Mesabi Range is from fifty to seventy-five miles north and northwest of Duluth. Its length along the strike is about 110 miles, and the length of its present productive area about eighty miles. The Cuyuna range lies southwest of Duluth nearly ninety miles, and is the last of the Lake Superior iron ranges to be developed. The relative positions of the ranges are shown on an accompanying map. The Mesabi Range is by far the largest producer and contains the largest ore reserves of the three. The Cuyuna is next in quantity of proven ore, and in production since 1916, while the Vermilion is first in average quality of ore.On the west, both Vermilion and Mesabi ranges disappear beneath heavy glacial drift; and on the east, extend into Canada, the so-called Gunflint range near the international boundary being an eastward continuation of the Mesabi formation. This latter range is of no economic importance, however, at present. The exploration and development of the Cuyuna range has proved up a considerable tonnage of manganiferous iron ore, besides ordinary merchantable iron ore."

Jan 1, 1920

By John J. Schanz

The ideal entering freshman for the College of Mineral Industries possesses the necessary aptitude to complete successfully a difficult technical curriculum, has a highly developed intellectual curiosity and adequate preparation in basic mathematics, sciences, and English, is enthusiastic about pursuing a career in the mineral industries, and puts forth a good academic effort while attending Penn State. The present programs of the University?s Division of Counseling and the College of Mineral Industries are directed toward providing the College with students who will meet these requirements. At present, freshmen are admitted to the Pennsylvania State University without entrance examination if they are in the upper two-fifths of their high school classes. All Pennsylvania students in the lower three-fifths are required to take the University Aptitude Test and all out-of-state students the College Entrance Board Examinations. Such students are admitted only if they score sufficiently high on either test to indicate the ability to do satisfactorily the work of University students. Only to this extent, are native intelligence and areas of greatest aptitude known for the Freshman prior to admission, and they are, therefore, largely beyond the control of either the Division of Counseling or the College of Mineral Industries. Because all freshmen, with exceptions that are numerically minor, are required to select a curriculum before admission to Penn State, each student who presents himself for required counseling during the summer, prior to his first semester, has already made a choice of his course of study. In many instances, such choices have been made without a rational and serious consideration of the student?s abilities and interests. Through tests given between the date of admission and the date of the counselling interview, it is possible to measure these characteristics and for the Division of Counselling to advise the student of his chances of success in his chosen curriculum. If he is qualified for the curriculum he has selected, Counselling Service goes on to direct the student?s attention to those other curriculums which are in the same general area as the one he has chosen and which will also challenge his abilities and correspond to his interests, Through this counselling, the curriculums of the College of Mineral Industries, which are often less well known to high school students than others for which they are no more qualified by ability or interest, are brought to the attention of the incoming freshman.

Jan 1, 1959