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By Robert B. Crookston

Oil from shale has been produced in foreign countries for more than a hundred years; however, except for short-lived, small operations, no commercial quantity of oil shale has yet been produced in the United States. Efforts to develop a viable oil shale process have been underway domestically for many years. At the present time, with the need for energy so urgently upon us, almost a dozen development ventures are underway or planned in Colorado and Utah. Of these several ventures, only Colony Development Operation has completed the development, testing and design of a ready-to-go 50,000 barrel per day com¬mercial project. Colony is a joint venture of the Atlantic Richfield Company, Ashland Oil Company, Shell Oil Company and The Oil Shale Corporation, more commonly known as TOSCO. TOSCO is the exclusive licensor of the TOSCO II retorting process and other oil shale technology, which includes mining, crushing and spent shale disposal techniques. This paper will deal, however, with only the materials handling aspects of the commercial oil shale operation. Oil shale handling for this infant industry is unique in that an understanding of the physical characteristics of the ore and the demands on material handling to the plant must he understood. Colony Development has completed ten years in the research and development of techniques and processes for mining, crushing and retorting raw oil shale and the disposal of spent or processed shale. A great deal has been learned about oil shale, in many cases confirming our intuitive analyses and the work of others, but more specifically we have brought it all together to a point where equipment performance and the specifications have been established and a design for the first commercial plant is now mature.

Jan 1, 1975

By Immo H. Redeker

This is a final progress report on a cooperative project conducted by three private feldspar companies,** North Carolina State University, and the federal Bureau of Mines. The object of the project was to reduce the feldspar tailings disposal problems at the flotation plants in the Spruce Pine area of North Carolina. The initial phase of the project revealed that high tonnages of saleable feldspar and quartz were lost in the tailings and the three feldspar companies are now concentrating their efforts on feldspar recovery, either by reclamation from the tailings as suggested by the Asheville Minerals Research Laboratory or by improvements in metallurgy in the existing plants.

Jan 1, 1970

By W. C. Dailey

The National Steel Pellet Company is owned by National Steel Corporation, managed by the M. A. Hanna Company and located near the town of Keewatin in northern Minnesota. Annually, the concentrator processes 15.24-Mt (15.0 million It) crude taconite with eight 8.2-m diameter by 5.5-m long (27 ft x 18 ft) wet semi-autogenous (SAG) mills to produce 4.57-Mt (4.50 million It) of iron ore pellets. To improve operating costs and primary mill grinding circuit efficiencies, a task force on liners was formed with the operation, maintenance and engineering staff at N.S.P.C. along with the local supplier of mill liners. Results of the task force recommendations since 1980 along with improvements made in the primary circuit operations, are presented. Mill Liner Design and Metallurgy Changes The primary mill liner task force was formed in 1977. Its function was to improve the operating costs and milling efficiencies of the ten 8.2-m x 5.5-m (27 ft x 18 ft) wet SAG mills that were operating at the time. The SAG mills are driven by two 3500 HP motors drawing a total of 5450 kW at 76% of critical speed.

Jan 1, 1985

By R. Bruce Thorndycraft

Heap leaching should not be chosen for development of a property solely on the basis of paper studies. Management should be made to understand where the risks are in heap leaching, and management should be alerted to the variability of costs in heap leaching, many of which are based upon company philosophy. These concepts are complex, but easily illustrated with guided tours of existing heap leach facilities.

Jan 1, 1998

By G. H. Friedrich

The distribution of mercury in soils, rocks, and ore was studied in three areas of the Pachuca-Real del Monte District: (1) An area north of the town of Pachuca where ore veins have been found at or near the surface. The mercury content of soil samples taken near the vein zones is far above the background value. The highest value was 1900 ppb (parts per billion) mercury in a soil sample above Veta Vizcaina; the background is about 50 ppb Hg. (2) In the area north of the town of Real del Monte where only a few of the veins are known to crop-out. Regardless of exposure, soils collected over veins show anomalous mercury values ranging from 250 ppb to 1900 ppb. (3) In an area south of the town of Real del Monte. Here, although vein outcrops are lacking, mineralization is known at a depth of about 120 m. All soil samples taken at 50 m. intervals along an east-west traverse contain anomalous amounts of mercury, with peaks corresponding with the known location of the veins.

Jan 1, 1965

By Madan M. Singh

A new mining project can raise questions about what effect it will have on the community after it closes. Historically, little was done by communities to plan for and accommodate the changes in the economic infrastructure when a mine project is finished either after the ore runs out or if market conditions deteriorate and make it unprofitable. Projects that were underfunded were generally unable to withstand periodic market downturns. However, data in a recent study conducted by the Seidman Research Institute leads to the conclusion that, even when a mining project is terminated, there can be (and, in the specific case studied, is) a residual beneficial economic effect in the community, which lasts for a long period of time.

Jan 1, 2010

By F. Brost

In 1976, a decision was made to install a conveying system to transport ore 10.3 km (6.4 miles) from the new Eisenhower Partnership Mine to Twin Buttes. The system, supplied and installed by Cable Belt Limited, of England, represents a radical departure from conventional conveyor systems. The driving tension is applied through two endless wire ropes while the belt acts only as the carrying medium. Features of the system are a single 2240 kw (3000 hp) drive and a 60° angle bend. Construction was completed in two years. Full production was attained after several months' operation.

Jan 1, 1979

By David G. Chedgy

It is probably safe to assume that most operating personnel working in coal preparation plants are exposed to noise levels in excess of the MESA Noise Regulations unless they are wearing ear protection. The excessive in-plant noise levels have received little attention until recently. Noise control has not been an important design consideration in existing coal preparation plants. This situation is rapidly changing as plant owners and plant operators are requiring that new coal preparation plants be designed to provide a safe noise environment for operating personnel and also meet MESA Noise Regulations. This paper discusses the noise exposure hazards, noise generating mechanisms, and some possible noise control solutions for typical coal preparation plants.

Jan 1, 1975

By Henry Chajet

Good morning, it is truly an honor to have been invited to speak before you today Before I begin my update on MSHA's activities, I?d Like t o quickly say a few words about the American mining congress and its mission in Washington, AMC is a national trade association representing most of the producers of the nation's metals, nonmetals and coal, we also represent the manufacturers of mining equipment and supplies and the financial and consulting institutions which service the mining industry. It is the diversity of our representation which gives us our greatest strength in our petitioning efforts, the administration and the members of congress know that an AMC position is the result of the careful consideration of a vastly diverse group of mining concerns. Our president, Al Overton, perhaps has the best description of AMC when he speaks of us as "the mining industry's eyes and ears and its collective voice in Washington."

Jan 1, 1981

By S. Acar, P. Somasundaran

Results of selective flocculation of natural ores containing two or more minerals and of synthetic mineral mixtures do not usually agree with what is expected on the basis of the results from single mineral tests (Acar and Somasundaran, 1985). This is mainly due to the ionic species released by the minerals, which act differently under different pH values. The objective of this investigation was to study 1) the surface chemical composition of selected sulfide minerals-natural chalcopyrite and pentlandite and synthetic covellite, millerite, and pyrrhotite-and 2) the changes brought about by the dissolved mineral species. Electron Spectroscopy for Chemical Analysis (ESCA) was used to perform the surface analyses.

Jan 1, 1991

By C. D. Harrison

The 1990 Clean Air Act Amendments specify national objectives for reducing sulfur dioxide emissions from coal-fired power plants System-wide reductions can be achieved by combining various emissions controls technologies and allowances, or compliance credits, that can be purchased, sold, or traded. As part of the Coal Quality Expert development project funded by U.S. Department of Energy and the Electric Power Research Institute (EPRI), Black & Veatch has developed an interactive computer tool, the Acid Rain Advisor (ARA). ARA allows the user to develop integrated system-wide compliance plans by comparing the costs and emissions reduction benefits for emissions allowances and various SO2 control technologies such as coal cleaning, fuel switching, and scrubber retrofits.

Jan 1, 1992

By Chee Theng

"Keep calm and carry on mining. That has long been the conventional wisdom in the mining industry, a largely cyclical one that has weathered roller-coaster booms and busts. But in the years from 2002 to 2016, an unprecedented steep rise in commodities prices that lasted a decade and then took a sharp turn downward had made it hard for gold and silver miners to stay the course.“The last 15 years highlighted some of the structural and inherent challenges that our industry has, from product price uncertainty to long lead times to the capital intensity of our business,” said Mitchell Krebs, president and chief executive officer of Coeur Mining, who was the luncheon speaker at the American Exploration & Mining Association’s 122nd Annual Meeting held Dec. 5-9, 2016, in Reno, NV.Looking back, Krebs said, “We were given this enormous gift of a commodities super cycle, and the industry kind of blew the opportunity.” While gold prices rose 319 percent and silver prices rose more than 200 percent over the 2002 to 2016 period, the XAU index of 30 gold and silver mining companies’ stock prices went up by only 20 percent.Entering 2016, precious-metals prices have made a comeback, with gold rallying strongly from a six-year low at the start of the year. This time, the industry is ready. Companies are leaner and meaner, with lower costs, reduced debt and an increased focus on higher grades and quality ounces. Although opportunities were missed in the past, the industry has got its act together and is now well positioned to take advantage of a price upswing and even to show profits when prices fall, as they did in August 2016, pushed down by a strong dollar."

Feb 1, 2017

By E. C. Winegartner

In producing and selling coal, the coal company is faced with many different parameters by which the quality of its product is evaluated. One type, which we choose to call the economic parameters, includes moisture, ash, sulfur, and Btu's. These are reasonably well understood by both the coal supplier and the customer, and the dollar values can be placed on them. This is the group of parameters of primary interest to most purchasing agents buying coal. A second group of parameters governs how the coal will behave in the boiler itself and is of primary concern to the engineers designing the boiler and to the men who must operate and maintain it. Since we have not yet learned to put dollar values on these parameters, they generally show up in coal contracts simply as cutoff points, the purchaser simply saying that he will not accept coal outside of certain limits.

Jan 1, 1975

By Richard M. Crowell

"As thorough sampling is usually expensive, the cost of a complete job is often unwarranted, and a cheaper approximation must be substituted. The engineer should, however, weigh the situation thoroughly before subscribing to an alternative other than an accurate assay basis on which to build his conclusion." Examination and Valuation of Mineral Property. R. Parks, 1949

Jan 1, 1994

By C. Waddell

PDMI mines five different grades of ore. Shovel operators were experiencing problems differentiating one material type from another. In 1997 PDMI decided to try GPS ore control to aid operators in identifying material boundaries. Computer generated ore control maps and GPS data defining the shovels' position is fed to a computer on board the shovel. A monitor, located near the shovel operator, displays material types, their boundaries, and the shovels' position and movement in relation to the mining face. This information has reduced errors in material identification by 50%.

Jan 1, 1998

By Brent Chamberlain

MARY KORPI: As has been typical today, our next speaker is filling in for one of his co-workers. Scott Lawson will be discussing "The Role of the Supervisor in Mining Operations" written by Brent Chamberlain of Independence Mining Corporation. Scott has more than 25 years in human resources management in the mining industry. He has worked in surface and underground mining environments in both precious and base metal mines. A graduate of Ohio University, Scott is currently manager of human resources at the Independence Mining Company's Cripple Creek and Victor Gold Mining operation located in Victor, Colorado. The only direction that I received from Scott was that he has to leave by 11:45 a.m. as he has a tee-off time with his boss at 1:00 p.m. Thank you to Scott for filling in today.

Jan 1, 1998

By Ruichen Ren, Xu Han, Caixia Li, Zengchuan Yue

In this paper, the size-density distribution of coarse middling coking coal (CMCC) with different grinding fineness and flotation concentrates was investigated. Then, the flotation behaviors and liberation characteristics of different size-density fractions in ground CMCC were analyzed, and the different size-density fractions were divided into five categories: mostbeneficial, secondary-beneficial, poorly liberated, insignificant-pollution, and serious-pollution. Based on the content of particles with different liberation characteristics, an evaluation index of the liberation characteristic of ground CMCC, namely, the liberation perfection index (LPI), was proposed. The results indicated that grinding changed the size-density composition of CMCC, which affected the flotation performance. Insufficient grinding and overgrinding were not beneficial to flotation. Insufficient grinding caused a higher content of poorly liberated particles and a lower content of most-beneficial particles. Overgrinding increased the content of serious-pollution particles and reduced the content of most-beneficial particles. The size order of the LPI values of different ground CMCC was consistent with the flotation efficiency, and the LPI values of the other two similar samples were overall positively correlated with their flotation performance, suggesting that the method is universal.

Feb 14, 2023

By James A. Clum

The shift to lower grade iron ores, e.g., magnetic taconites, resulted in a shift towards agglomeration practices which could effectively deal with the fine particle sizes generated in the liberation and concentration processes. If the iron bearing particles are not extremely fine, e.g., -1/2 in + 100 mesh, sintering is an adequate means of agglomeration.(1) For the more dispersed ores which result in fine concentrates (more than 80%,-325 mesh), the fine particles must be agglomerated by mechanical means before final hardening, e.g., pelletizing.(1) In the pelletizing process, the essentially mechanical step of balling is extremely critical since the strength of the pre-fired pellet determines the firing conditions. The ability of the proper amount of moisture to hold together a ball of the very fine ore concentrate particles has long been recognized. It is a charac¬teristic of the reaction at the interface between the ionic solid of the ore concentrate and the polar water phase which overlays the solids. The strength in such moisture laden balls, the green strength, is a strong function of the water content (Figure 1) and thus deteriorates rapidly for either a small excess or a small deficiency of moisture. For purposes of commercial practice, the control of green ball handling properties by accurate control of ball moisture is too demanding. Moreover, as the ball is heated towards its hardening tempera¬ture, e.g., 1300'C, there is a substantial drying reaction which would lead to such a low dry strength of the ball that it would not support its own weight much less the weight of other balls in a firing furnace.

Jan 1, 1976

By Edward R. Mueller

As an alternative to a million dollar, sensor based, computer dispatching system, Cyprus Pima Mining Company has installed a home¬made analog computer. The device is used in conjunction with a standard radio-dispatching system; it is inexpensive and very simple to build and operate. It enables the dispatcher to make near opti¬mum dispatching decisions and to identify all off schedule haulage trucks. Since installation, Cyprus Pima has experienced significant increases in pit productivity.

Jan 1, 1977

By D. L. Moellenberg

Under various state laws enacted mostly within the last 20 years, reclamation requirements and standards for hard-rock mining operations have been established virtually everywhere in the western United States. Unlike the uniform and detailed coal mine reclamation requirements under the federal Surface Mining Control and Reclamation Act ( "SMCRA" ) and state programs mode led after SMCRA, the various state law hard-rock mine reclamation requirements are based upon a variety of objectives, and therefore are subject to varying standards from state to state. While the diversity of reclamation requirements complicates the determination of what reclamation measures will be required at any particular mine, there are valid reasons for this diversity. There are dozens of different commodities mined in the United States, and mining methods are different for each commodity. Local natural conditions such as climate, precipitation, geology, hydrology, and biology vary widely across the county. Site-specific conditions also affect mining and reclamation methods. Also, factors such as economics, land use, and environmental protection issues receive different priorities in different states and communities within those states. State reclamation requirements in general provide the flexibility to consider site-specific circumstances, allowing operators to design and engineer the best reclamation measures for each mining site. To the mine developer or manager, reclamation requirements must be translated into design, operational, and closure measures for mine planning. Each of these measures must then be assigned additional costs to be factored into the economic decisions for a particular mining operation. On a broader level, reclamation costs must be factored into decisions such as where to invest in exploration and mine development. The purpose of this paper is to provide a summary of the state non-coal mine reclamation requirements in twelve western states. This summary comparison may be useful as a starting point in considering how local reclamation requirements will impact potential mining costs.

Jan 1, 1994