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By M. G. Ayat

I have been following the discussions on coal degradation started by the article "Degradation process in coal slurry pipe-lines," by M.G. Ayat and B.C. Scott. I agree with Mr. Dasher's comments in January that the title of the article was perhaps misleading as the information appeared to pertain more to processing the coal than to transportation. Specifically, the authors' conclude that the cyclone had an important impact on the degradation. Dr. Ferri's comments on degradation in other physical processes was very correct, handling of coal in a turbulent manner has an impact on the size distribution of the coal. This is one reason that when I design a coal system (mine to rail car) I try to minimize the total number of transfer and processing steps consistent with achieving the desired product specifications. Another area, mentioned in passing in the article, the impact of natural causes and the mining step, is of particular interest to me. A mine in West Virginia had a variation of 50% in the -6.35 mm (-0.25 in.) raw coal depending upon the direction of mining. Since it was a single unit mine, this significantly impacted the final product. Two articles on mining's impact on size distribution are: • Stefanko, R., Chopra, I. K., and Ramani, R. V., 1974, "Mining influence on size consistency and washability char¬acteristics of coal," SME Fall Meeting. September; and • Albrecht, M., and Olsen, D., 1980, "Mining methods impact on coal preparation plant design." 1st International Mine Planning and Development Symposium. September. Both articles presented information on variation of size distribution and cleaning plant performance on a coal depending on the mining method used. Both articles considered a single coal seam at one mining operation. Stefanko's article considered continuous and conventional mining of coal in Pennsylvania. Albrecht's article considered surface, underground continuous, and underground hydraulic mining of a coal in British Columbia. Both concluded that mining methods do impact coal characteristics. I agree with Mr. Ayat's comments in reply to Dr. Ferri's discussion, "... degradation is a multi-faceted phenomenon involving many natural and man-made factors." As efforts are being made to produce a higher quality (lower sulfur) coal, this topic becomes even more important

Jan 1, 1990

By Earle Faig

Along with other transportation modes, the barge industry will be greatly effected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country's energy program. Perhaps even more significantly, a series of events have caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of our long experience in moving large quantifies of coal, the barging industry is in an excellent position to capitalize on coal's increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to the barging industry. Barge companies operate on a 40.23-Mm (25 000 mile) river system which includes the East and West Coasts and the Mississippi River System. Included in the Mississippi River System are the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior - Tombigbee and Mobile Rivers as well as some smaller tributaries. The Gulf Intracoastal Waterway, which stretches along the Gulf Coast from Brownsville, Texas to Apalachicola, Florida, is also considered part of the inland waterway system.

Jan 1, 1981

By L. Meier, M. Dennis, J. Schieffer, K. Murray

"INTRODUCTION Contrary to popular belief, Arizona State Trust land is not public land. All uses of the land must benefit the Trust, a fact that is considered with the review of each application received for sale, lease, or permit. This includes applications for activities ranging from commercial development to recreation. In 1863, the Territory of Arizona was established by an act of Congress. This act reserved sections 16 and 36 in each township to be held in trust for the benefit of the common schools. Later, the Enabling Act of 1910 allowed the Territory of Arizona to prepare for statehood. This act reserved the additional sections 2 and 32 of each township for the common schools and granted another 2,350,000 acres to be held in trust for other beneficiaries. In all, Congress granted the State of Arizona almost 11 million acres. The State was to manage those lands and maximize revenue for 13 separate beneficiaries. To meet this mandate, the State established the Arizona State Land Department (ASLD) in 1915. During fiscal year 2015, the ASLD contributed $136 million to the permanent fund, bringing the total value to over $5.1 billion, through the sale and leasing of the land and natural products which includes minerals. The current inventory of State Trust lands includes 9.2 million acres representing about 12.7% of the State.The ASLD Minerals Section manages the exploration, development, and leasing of mineral products on State Trust land. We are not a regulatory agency, but a department guided by our fiduciary responsibilities to the Trust. Our mineral programs include: Exploration Permits, Mineral Leases, Mineral Material Leases, Geothermal Leases, Oil & Gas Leases, and Special Land Use Permits. INDUSTRIAL MINERALS ON ARIZONA STATE TRUST LAND Industrial minerals fall under the category of either Mineral or Mineral Materials Leases. Common industrial minerals found on Arizona State Trust land include potash, limestone, gypsum, salt, specialty clays, zeolites, crushed stone, and sand and gravel."

Jan 1, 2016

By G. W. McMahon

Following the Sago Mine accident, the U.S. Mine Safety and Health Administration (MSHA) asked the U.S. Army Engineer Research and Development Center to study several possible methane explosion scenarios in the Sago coal mine. The study used a 0.3-m (1-ft) resolution map of the mine to produce a 3-dimensional (3 D) model of a portion of the mine, including the sealed area where the explosion occurred. An advanced 3 D computational fluid dynamics (CFD) code was used to calculate the explosion pressures within the sealed area, on the mine seals and in nearby regions of the mine. Based on the best available information on methane concentrations and assumptions on homogeneity and on layering and mix composition, three separate initial conditions of methane-air concentrations and location were studied. This paper discusses the CFD modeling technique, the results of the calculations, the challenges of conducting this type of modeling and the advantages and limitations of CFD modeling of accident investigations of mine explosions.

Jul 1, 2010

By John G. Kuhm

INTRODUCTION The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an orebody, no more and no less. This cost of development drilling represents a large part of the total development budget. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. This high development cost factor has produced a quantity of research to develop techniques, for efficient control of drilling programs. Recent mining literature is full of articles describing methods for measuring and increasing the effectiveness of these expensive projects. The method described in this paper was developed during the latter part of a major development drilling project at the Christmas Mine of Inspiration Consolidated Copper Company in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. This technique was used at Christmas as a practical means for evaluating adequacy of drilling on an individual hole basis, and it was possible to eliminate several previously approved holes. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous orebodies of the porphyry-copper type would be the most likely candidate for application of the technique. Discontinuous orebodies would not be amenable to this technique. The method is based on the measurement of the linear correlation between the spatial distribution of two sets of data. The Pearson product-moment correlation coefficient is used. This is a standard statistic commonly used to measure linear correlation between two sets of data. The statistical significance of the correlation coefficient at a 95% confidence level is the main criterion for controlling the project. For purposes of reference we will call our technique the "correlation method" in this paper.

Jan 1, 1971

By W. M. Husslage

The permeability in the blast furnace shaft is adversely affected by low temperature reduction degradation of sinters. The fundamental cause is an expansion of the iron oxide phase resulting from reduction of hematite to magnetite. The present study showed that expansion behavior during the hematite / magnetite reduction step and the resulting microstructure are strongly influenced by the reduction temperature (viz. partial oxygen pressure), the reducing agent and the nature of the hematite. The reduction rate is of minor importance. A reduction mechanism is proposed, explaining the dilation behavior and the magnetite microstructure. The results can provide better insight into reduction degradation behavior.

Jan 1, 1998

By Elgin D. Bell

Within the next, year or two, Western Canada should overtake Mexico and France. to become the worlds second largest producer of elemental sulphur, surpassed only by the United States, By 1965, it should produce about 25% of the world's total elemental production and, about 10% of sulphur produced in all forms. In 1952 Alberta had but one small sulphur recovery plant. By 1962, it had fifteen plants with a total designed capacity of almost 6,000 long tons of sulphur per day and actual production of almost one million long tons per year. This decade of dynamic growth was the result of Alberta's rapidly developing natural gas industry. More particularly it was the result of approval in 1960 to export natural gas in large volumes into the United States. Prior approval to export gas from Alberta to eastern Canada and relatively modest volumes to the U. S. had resulted in the construction of several plants but none were of the scale required to serve the U. S. market.

Jan 1, 1963

By Xinyang Wang

It is believed that sulfur and volatile matter contents in coals are the main intrinsic properties to cause the self-heating of coal. Their oxidation at lower temperatures than that of fixed carbon to initiate coal's self-heating should be quantified. This study is aimed to improve the previous mathematical model developed by the authors for studying the coal's propensity for spontaneous combustion. It enhances the model's ability to consider the effects of sulfur, volatile matter and moisture contents in the coal - three important factors affecting the coal's self-heating process. Sulfur exists in coal primarily in the form of pyrite which will be oxidized rapidly under suitable conditions. Volatile matters, higher in low rank coals, are more easily to be oxidized. Heat of water condensation provides initial energy for low temperature oxidation. Heat release rates for pyrite oxidation and moisture condensation are built in the model. Finally, the simulation results in terms of time versus temperature on pyrite oxidation and moisture condensation are validated with the adiabatic testing data respectively.

Jan 1, 2013

By F. Calizaya

A booster fan is an underground fan installed in series with a main surface fan and used to boost the air pressure of the ventilation air passing through it. To accomplish this objective, the fan is installed in a permanent stopping and equipped with airlock doors, a monitoring system, and interlocking devices between main and booster fan controls. The stopping and doors are used to prevent flow recirculation, and the monitors to ensure safe operation of the fan. A booster fan, properly sized and sited, can be used to create safe work conditions and allow the extraction of minerals from areas that would otherwise be uneconomic to mine. In deep and large mines with heavy emissions of air contaminants, the required quantities of air can only be supplied by using high pressure fans. These fans will inevitably induce significant losses of fresh airflow through the stoppings and doors. For well defined ventilation circuits, booster fans can be used to decrease the main fan pressures and reduce the leakage flows. However, this will require a good understanding of the correct ventilation practice, from planning to operation and maintenance of booster fans. The objective of this study is to investigate the conditions under which booster fans can be used safely and efficiently in underground coal mines. Specifically, the study is directed at (1) collecting reliable information on airway resistances and flow requirements from two large U.S coal mines, (2) collecting fan performance data from one or more existing coal mine where booster fans are used regularly, (3) monitoring the performance of booster fans in a laboratory model and an experimental mine, (4) developing a booster fan selection method to assist the ventilation engineer at the planning stage, and (5) training six M.S. or Ph.D. graduate students in advanced mine ventilation.

Jan 1, 2010

By T. M. Yegulalp

A new explanation of the scale dependency of the strength properties of rock is presented based on the theory of extremes. A review of past work on specimen size strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect on the statistical properties of the strength distribution. It is shown that the weakest link theory is directly related to extremal statistics and properties of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1992

By Paul H. Johnson

Chemical mining may be defined as the in-place extraction of metal values from ores located within the confines of a mine (that is, broken or fractured ore, stope fill, caved material, or ores in permeable zones) or ores located in dumps, prepared ore heaps, or tailing ponds. The term solution mining has, in general, been used to mean the in-place dissolution of water-soluble mineral salts with leach solutions. Chemical mining is presently in its embryonic stage. Basic research needs to be done to understand the influence of physical and chemical factors in chemical mining, and applied research needs to be done on both a small and a large scale to develop practical techniques of field practice. The areas of research include the following: (1) Leaching chemistry, the influence of physical, chemical, and biological factors in in-place leaching (2) Hydrodynamics of chemical mining systems (3) The development of new, as well as old, leaching agents for use under chemical mining leach conditions (4) The development of new means of contacting fine and coarse materials (with solutions) under static leach conditions (5) The development of new processes for generating and regenerating chemical mining leach solutions (6) The development of metal recovery processes

Jan 1, 1969

By C. L. Lin

The characterization of rare-earth resources in 3D is now possible using high-resolution X-ray microtomography (HRXMT) to describe ore texture and mineral phase composition. In addition, detailed texture analysis, including grain exposure and mineral association, can be described. Preliminary examination of a sample of Mountain Pass ore is reported to describe the spatial distribution of the mineral phases (calcite, barite and bastnaesite), particularly the grain size distribution of bastnaesite. The examination includes analysis of selected particle size classes to determine the appropriate size for liberation of the rare-earth mineral bastnaesite. Good liberation is expected to be achieved if the material is ground to a top size of -150 µm.

By Peter Bush

The deposition of metastable carbonate minerals in ar. aid, sheltered, coastal environment, leads to the formation of a flat, coastel, sabkha plain. The ground waters of the sabkha plain are modified by evaporation, precipitation of salts and reaction between ions in solution and the host carbonates. The resulting brine is similar to those found in fluid inclusions associated with Mississippi Valley type deposits. The aragonite and high magnesium calcite found in the sediments can concentrate lead and zinc from sea water. On diagenesis the lead and zinc are released into the sabkha brines.

Jan 1, 1979

By J. G. Groppo

A series of performance studies have been conducted using counter-current column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia and utilized a 0.15m (6 in.) I.D. column that was 5.79m (19 ft.) high. The refuse streams tested included both thickener feed and classifying cyclone overflow with a typical size distribution of 100 mesh X O. The percent solids of the column flotation feed varied from 1.5 to 15% while the ash content ranged from 30-60%. The concentrates produced contained 2-10% ash with BTU recoveries of nearly 90% using 0.12-1.25 kg/ton (0.25-2.5 lbs/ton) fuel oil and 0.12 kg/ton (0.25 lb/ton) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from 7 different seams are discussed as well as scale-up relationships utilized to design a full scale installation presently in operation.

Jan 1, 1990

By H. Sevim

In a recently developed long term open pit production planning model, the optimum plan is found by exhaustively searching through nested pits of maximum-metal contents. A more efficient, dynamic programming (DP) based search algorithm now replaces the exhaustive search algorithm which was requiring prohibitively long execution time in real life cases. The logic and the formulation of the newly developed search algorithm are illustrated through a small hypothetical case. A real life gold deposit is treated to demonstrate that the algorithm does indeed find the optimum production plan among all possible plans. A comparison, in terms of computational savings between the two algorithms is also given.

Jan 1, 1994

By Evan J. Owen, Virginia T. McLemore

Rare earth elements (REE) and critical minerals are increasingly becoming more important in our technological society and are used in many of our electronic devices (such as cell phones, computer monitors, wind turbines, etc.), batteries, and magnets. Measuring REE and critical minerals in ashed coal approximates the REE and critical minerals in the fly or bottom ash remaining after coal is burned at a power plant, where REE and other critical minerals could be leached. In New Mexico, there are 26 coal fields in Late Cretaceous rocks in the San Juan and Raton Basins. These rocks are being characterized as part of the DOE’s CORE-CM (Carbon Ore, Rare Earth, and Critical Minerals) program. Higher concentrations of REE (as much as 2103 ppm total REE) are found locally in ashed coals from the basins. More chemical and mineralogical analyses are required to fully understand the distribution and origin of REE in these deposits. As the demand for REE increases because of increased need and short supplies, the dollar value per ton of ore rises, enhancing deposit economics, perhaps even from coal.

Feb 1, 2025

By Connor Langford, Murray Gant, Ken Massé

For public organizations, preparing accurate project cost estimates is a critical component in capital project planning. Project delivery methods provide a structured approach to moving projects through the design and construction lifecycle, and typically use cost estimates as key inputs at each stage to determine if the project will advance. As design stages can occur years or even decades before construction contracts are awarded, estimates need to make reasonable assumptions about how the work may be executed (means and methods) as well as potential future market trends so that appropriate values for material pricing, labour costs, escalation, and owner’s costs can be included. This process is challenging enough during stable markets, as historic trends can often be misleading and require a suitable understanding of economic factors to use appropriately. When you mix in the market volatility that has been observed since 2020, developing accurate project cost estimates becomes even more challenging. In cases such as this, having a structured approach to cost estimating that includes an adequate risk-based reserves cannot be overstated as it provides the basis for ongoing project decisions. This paper explores some of the historic and more recent market trends that have impacted key aspects of project cost estimates for capital project planning. It also provides recommendations on how to develop cost estimates for infrastructure projects, with examples from Metro Vancouver, which plans for and delivers regional-scale services to 2.6 million residents. A brief commentary on the use of escalation clauses in contracts is also presented.

Jun 13, 2023

By T. N. Andersen

The history of gold and silver analyses shows an interesting duality. On one hand, classical chemical and instrumental methods have evolved to meet changing needs, but on the other hand, the age-old and somewhat empirical fire assay has remained a popular tool. Inasmuch as gold and silver generally have been present in ores at low concentra¬tions, methods have been challenged by a need for sensitivity and selectivity coupled with reasonable assay time. A progressive increase in the importance of low grade materials as ore sources has led to the need for improved methods. Assays of these materials are required for process control and accounting in operating plants as well as for guiding research and development activities. The analytical response to these needs is evidenced by numerous reviews published through 1977-¬e.g., cf Kolthoff and Elving (1966), Beamish and Van Loon (1966, 1972, and 1977), Young (1971) , Mallett (1970), and Sen Gupta (1973). In this paper we present a brief sketch of the history and status of various gold and silver methods. A more detailed summary of atomic absorption spectroscopy (AAS) is Given, as this method has gained in popularity more than other assay methods. AAS methods currently in use are summarized and discussed briefly. This paper is not meant to be a detailed review, as are the above mentioned publications. Rather, we borrow from those works and more recent papers to report trends in gold and silver analyses (particularly in AAS). Also, we discuss some selected poten¬tial problems, and problems that have been experienced by this laboratory.

Jan 1, 1981

By Dirk van Zvl

The design of cover systems for reclamation schemes in tailings requires estimation or determination of tailings materials properties such as compressibility, shear strength and consolidation characteristics. It is very difficult and expensive to obtain truly undisturbed tailings samples for laboratory testing. In situ testing methods have been developed for economically obtaining large amounts of information. Two of these methods are described, the piezocone and the flat plate dilatometer. Both of these methods provide a rapid means of detailed material identification in a nearly continuous fashion for the entire depth investigated. The equipment is described and typical data from a uranium tailings impoundment is presented. The results are compared and the advantages and disadvantages of these methods are discussed.

Jan 1, 1984

By James R. Walpole

Less than 100 years ago the first major federal regulatory agency, the Interstate Commerce Commission was established (in 1887), and since that time literally hundreds of other federal agencies have been created. The regulations set by these agencies tremendously affect the individual citizens of this country as well as U.S. institutions. A few examples of the myriad agencies established include the Food and Drug Administration. (1907), the Bureau of Mines (1910), the Federal Reserve System (1913), the Federal Trade Commission (1914), the Tennessee Valley Authority (1933), the Securities and Exchange Commission (1934), the National Labor Relations Board (1935), the Small Business Administration (1953), the Federal Maritime Commission (1961), the Equal Employment Opportunity Commission (1965), the Farm Credit Administration (1971), etc., etc. Eight years ago, on December 2, 1970, still another federal agency was established by the reorganization plan of President Nixon -- the Environmental Protection Agency (EPA). The Administrator of EPA was given authority to regulate certain activities affecting the environ-ment, which were formerly within the jurisdiction of the Department of Interior, the Department of Health, Education and Welfare, the Federal Radiation Council, the Atomic Energy Commission, the Department of Agriculture, etc. Within weeks after the formation of this Agency, Congress began to enact legislation which would be administered by EPA. Over the last eight years a considerable number of such laws have been passed, a few of which include: the Clean Air Act (1970), the Noise Control Act (1972), the Federal Water Pollution Control Act (1972), the Marine Protection, Research, and Sanctuaries Act (1972), the Federal Insecticide, Fungicide and Rodenticide Act (1973), the Safe Drinking Water Act (1974), the Toxic Substances Control Act (1976), the Resource Conservation and Recovery Act (1976), the Clean Air Act Amendments of 1977, etc. It may be helpful to review, in a summary fashion, the major provisions in some of these statutes, and accompanying regulations, as they relate to water quality control in the mining industry. The Safe Drinking Water Act and the Federal Water Pollution Control Act contain provisions to be examined, as well as the Resource Conservation and Recovery Act and the Toxic Substances Control Act. One other law, the Surface Mining Control and Reclamation Act (1977), is not administered by EPA although it does contain many provisions related to environmental control, and it will also be dis-cussed because of its importance to the mining community.

Jan 1, 1978