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By Robert N. Evans, Delon Hampton

During construction of the Washington Metropolitan Area Transit System, the hand-mining of a mixed-face condition was anticipated on a portion of tunnel located in the downtown area of Washington, D.C. The Section, consisting of two circular tubes, extends from Station 12+80, heading in a westerly direction, traverses along a curve under Lafayette Square, and ends in a northwesterly direction at Station 37+62 (see Fig. 1a). It was near the northernmost portion of the section that the mixed-face condition was encountered. Decomposed rock was first encountered in the invert at Station 31+00. From this point the rock gradually increased in height until it intersected the springline at Station 37+62, the project limit. Summarized within this paper are measurements of the soil load on a horseshoe-shaped portion of tunnel located in the mixed face condition. These measured loads are compared to the soil load on tunnels as determined by current design methods. The paper also discusses rib and surface movements associated with the post loading process. Comments will be made on how the presence of a mixed face condition might help or hender the tunnel design and construction procedures.

Jan 1, 1974

By J. Herbst, I. Heber-Panu, Dan G. Cojocariu, E. Ene-Danalache, G. Poling

A general model which represents not only batch but also continuous flotation in multi-cell machines is presented. This model considers both the size distribution and the distribution of flotabilities in a size class for valuable mineral particles in the pulp. The general expression is shown to reduce to several previously reported models. In addition, a number of new models are found to arise for different specific assumptions concerning the flotability distribution and/or the size distribution of the particles undergoing flotation. Several of these new models are tested experimentally using laboratory-scale batch and pilot-scale continuous data. Model parameters are estimated from this data and a comparison of calculated recoveries and those experimentally determined are presented. Finally, the influence of the feed rate, aeration rate and valuable mineral content of the feed on the recovery is examined.

Jan 1, 1976

By S. C. Suboleski, J. W. Oberholzer

This paper describes research being undertaken by the Chamber of Mines Research Organization (COMRO) to assist the continuous miner operator and section foreman in the performance of their jobs. The project will initially provide visual assistance to the miner operator, and later it will semiautomate the mining (cutting) process. Using a technique known as "RF tagging," the project will also provide the section foreman with real-time or near-real-time information about the performance of the loading and hauling units. This data will allow the section foreman to quickly detect problems and take action where appropriate. The project is based upon the application of currently available technology, and in-mine testing results from the first phase are now available.

Jan 1, 1994

Up to the middle of 19 14, when I had reached what seemed like the advanced age of 30, I had enjoyed far more than my share of success and a lot of minor adventure. But the exciting experiences in distant lands that Soldiers of Fortune had made me long for had not yet materialized. And I had not accomplished the two goals that Mrs. Hughes' geography class at Belmont had set up for me. They were to see In its tropical home the enormous yellow bill of the toucan bird and to ride on a straw "bolsa" on Lake Titicaca. These aims were gratified In the next five years that were the epitome of "romance" in its German connotation of facts seen through the rosy glasses of imagination. Dr. Louis Ricketts was to a large extent responsible for my opportunity. I had been lucky enough to do a lot of work for and with the Doctor, as he was affectionately called by the mining men of the southwest. My association was in connection with his work with John Greenway on the complex metallurgical problems at Ajo. Soon after the Ajo investigation Ricketts had been made chief consultant for the Anaconda Copper Co. When Anaconda decided to undertake a cam- paign of exploration of the west coast of South America Dr. Ricketts thought of me and arranged with Greenway to give me a leave of absence from my Calumet and Arizona job. It took three days in New York in June 1914 to arrange the expedition. Ben Thayer, executive vice president of Anaconda, did most of the planning and I was to report to him. T.H. France, a 45-year-old mining engineer who had been driven out of Mexico by the Madera Revolution, was to accompany and help me. He spoke excellent Spanish and his years of Mexican experience had taught him how to get along with Latin Americans. He went ahead to Bolivia, our first target, to get an idea of the country and the problems. This was lucky as I hardly knew where Bolivia was.

Jan 1, 1976

By Lit-Mian Chan, David H. Carlson, John H. Johnson

This paper presents an apparatus and procedures to implement a methodology for controlling ambient air quality in a confined working environment, such as an underground mine, an underground storage area, or a tunnel. The air quality control methodology is directed at limiting the quantities of exhaust pollutants emitted by diesel-powered vehicles into the confined space by identifying vehicles that are excessive polluters. The methodology is based on tailpipe and ambient air measurements in the confined space, and the ambient air threshold limit values (TLVs) for the various diesel exhaust pollutants. The methodology consists of two computational methods; a deterioration criteria computational method to identify excessive polluting vehicles, and an engine performance computational method to determine engine performance and to provide information needed to diagnose engine faults. The methodology is designed for implementation in conjunction with a preventive maintenance program. The first part of the paper describes the mine air and tailpipe emissions measurement apparatus and techniques used to obtain data. This is followed by sections discussing the deterioration criteria and the engine performance computational methods. A section discussing some common engine emissions-related faults is also presented. Lastly, a proposed procedure to implement the methodology including a possible hierarchical structure for mine personnel involved to implement the procedures is presented.

Jan 1, 1993

A charge of the Research Council of the Society for Mining, Metallurgy and Exploration, Inc. (SME) is to ?? identify longer term research ideas/needs, that in the perception of the SME Research Council, could represent significant technology breakthroughs ?? (SME, n.d.). In 2008, the Council decided that instead of unilaterally developing a list of top priorities, it would involve the entire membership of SME in identifying the top priorities. Additionally, it decided to keep the list short. This paper describes the process and results from that exercise.

Jan 1, 2010

By V. A. Evans, D. L. Hellier

Introduction Preparing a report on fluorspar economics in the US could have been somewhat complicated at one time. This was because the number of producers, both large and small, derived production from different locations through-out the western US and the southern Illinois and western Kentucky fluorspar districts. Companies, such as Allied Chemical and Williamson Mining, operated in the Jamestown district of Colorado. In Walden and Salida, CO, the Colorado Fluorspar Co. operated mines and mills. In New Mexico, both Du Pont and Allied had mines and mills. In the Illinois-Kentucky district, US Steel, Rosiclare Lead and Fluorspar, Minerva Oil Co., and Marathon Oil all produced spar for the US market. Now all of the companies are out of the fluorspar business and, with the closing of the Seaforth Mineral Co.'s Inverness Mining Co., only Ozark-Mahoning Co. survives as a domestic producer. History Ozark-Mahoning Co., as it now exists, was formed in 1946 by the merger of Ozark Chemical Co. and Mahoning Mining Co. Ozark Chemical Co. was started in the 1920s to produce sulfuric acid for two refineries located in Tulsa, OK. Mahoning Mining was originally formed by the founders of Ozark Chemical Co. and the Youngstown Sheet and Tube Co. to produce fluorspar and associated minerals from properties in the southern Illinois and western Kentucky fluorspar district. In 1937, Mahoning Mining started an exploration program, employing contractor-operated churn drills to look for reserves in Hardin and Pope Counties in southern Illinois. Based on known reserves in the area and the results of the exploration program, work was started in the fall of 1938 to build a selective flotation plant at Rosiclare, IL. The mill was completed and put into operation in August of 1939. The company's first mining efforts were in the Cave-In-Rock district just north of Cave-In-Rock, IL. The deposits in this area were of the Manto or bedded type. They have been the mainstay of the company's operations in the Illinois-Kentucky fluorspar district. In 1950-51, the company expanded its operations by purchasing fluorspar properties from Colorado Fluorspar Co. at Walden, CO. This location was operated from 1952 through 1958 and from 1968 through 1973 when it was closed permanently. In 1974, Ozark-Mahoning Co. was purchased by Pennwalt Corp. Presently, it is a wholly-owned subsidiary of that corporation. As the only major domestic producer of fluorspar in the US today, the company's ability to survive under the flood of imported material is directly related to the four major segments of its operations. These are: exploration, mining productivity, maintenance, and marketing. All are done in-house. Exploration The Southern Illinois fluorspar district is located in the most complexly faulted area of the central US. The formations are sedimentary in nature and range in age from Devonian through Pennsylvanian. The deposits are small, they range in size from a few thousand tons up to 900 kt (1 million st), with the average minable deposit being around 544 kt (600,000 st). The ore occurs in both nearly vertical vein deposits and in Manto or flat lying bedded deposits. Due to the relatively small size of the deposits and the depth at which they occur, a good low-cost exploration program is essential to ensure that new finds of ore are equal to the mining extraction rate. Ozark maintains a leased land position in Pope and Hardin Counties that will fluctuate somewhere between a low of 40 km2 (10,000 acres) up to a high of 129 km2 (32,000 acres), depending on total size of tracts leased. Most all lands are obtained through a standard lease purchase option, with a small minimum royalty per acre during the normal 10-year option period. All leases are standard and without deviation to control land cost. All land leasing is done through Ozark's geological staff, who also

Jan 11, 1986

By David B. McWhorter, John D. Nelson

INTRODUCTION The quantity of seepage that will be released from a tailings impoundment depends not only on the characteristics of the seepage control system, but also on the properties of the foundation soil or rock beneath the impoundment and the nature of the groundwater in the area. The interaction between various elements of the seepage control system and the influence the various characteristics of the site and impoundment have on seepage are the subject of this paper. The results of analyses are presented herein to indicate the nature and magnitude of the effect that the various factors will have on seep¬age losses. Analyses were conducted for a uranium mill tailings impoundment located in an area characteristic of many found in the western United States or Canada. A typical seepage control system consists of placement of either a clay or synthetic liner beneath the impoundment. In some cases an underdrain system may be placed on top of the liner to collect drainage from the tailings. The parameters that were varied in the analyses included those pertaining to the liner, underdrains and foundation strata. In general, it is shown that the seepage losses will vary in a complex manner depending on the interaction of the elements of the site and the seepage control system. As may be expected, the liner and underdrain systems have the most pronounced effect on controlling seepage. This paper deals with the quantity of seepage released from an impoundment However, the impact that seepage losses from an impoundment will have on the surrounding environment will depend on the rate at which contaminants will enter the groundwater and the nature of the groundwater flow itself. Consequently, when considering these results with regard to environmental impact they must be interpreted along with considerations of geochemical factors. MECHANICS OF SEEPAGE The mechanics of seepage and methods of analysis that were used will be discussed briefly herein. For a more detailed discussion the reader is referred elsewhere (McWhorter and Nelson, 1978, 1979, 1980). A general column through the impoundment was considered to be as shown in Fig. 1.

Jan 1, 1980

By L. G. Stolarczyk

In-mine Continuous Wave (CH) Radio Imaging method (RIM) instrumentation has the capability of measuring EM wave propagation constants in layered formations. The RIM method is based upon the fact that seams of coal, trona, potash, quartzite, gilsonite and oil bearing sands form natural waveguides for low loss transmission of electromagnetic (EM) waves. The waveguide forms whenever the seam is bounded by more conducting claystone, mudstone, shale or in the case of oil/gas traps, by a floor of saline water. Disturbances caused by faults, shear zones, paleochannels, sills and dikes significantly alter the propagation constant. The analytical values of the EM wave propagation constants depend on the physical and electrical parameters of the seam. The values are presented in this paper in a graphical form to assist in the interpretation of RIM tomographic images. This paper compares in-mine geologic mapping obtained during mining to tomographic images of the geologic disturbance zones in a Central Utah coal mine.

Jan 1, 1989

By Norman K. Olson

Hard-rock phosphate was formerly the chief source of all phosphate in Florida. Its mining began as early as 1883 or 1884, reached a peak level in 1907 and ceased in 1966. Production began and ended in the Dunnellon area (Marion County). Nearly all the hard-rock was exported because its P205 value per unit weight is generally more concentrated than that of other phosphate rock. Maximum production, achieved in 1907, was greater than 600,000 tons; the total value for that year was more than $4,000,000. The Florida hard-rock phosphate, considered to be of middle Miocene to early Pliocene age, has an intermittent narrow, linear northwest-southeast trend. The Ocala uplift controls the phosphate distribution for more than 200 miles. Other known, isolated hard-rock areas appear to be related to minor folds on the Ocala uplift. The hard-rock phosphate deposits are a heterogeneous mass of sedimentary fluorapatite, chert and quartz with textures ranging in size from clay to boulder, and in thickness from 0 to 40 feet. Phosphate compounds, principally fertilizers, have been in oversupply since before 1968, but by the middle 1970's some experts forecast a supply-demand balance. A brighter future for exploitation of Florida hard-rock phosphate depends upon one or more of these factors: 1) depletion of present premium grades (74 percent BPL and above) of land-pebble; 2) cheaper electric power from nuclear generators for profitable electric furnace operation; 3) supply and price of sulfur; 4) manageable rail-water transportation costs; 5) development of less costly mining and separation methods; and 6) minimum competition from high-grade foreign phosphate.

Jan 1, 1972

Mill #4 processes mildly refractory ore from Carlin Trend deposits. Diagnostic analysis of plant operating data was used to generate a mathematical model containing the key parameters influencing the gold recovery. The model was used to direct modifications to plant operating practice. The cyanide dosing strategy was changed to reduce preg-rob gold masses and cut reagent consumption A finer grind was achieved without capital investment. The density in CIL was lowered, and tighter control was exercised over plant throughput. These changes resulted in a recovery increase of at least 2%, worth $111,000/month at $300/oz, and concomitant reagent cost savings of $55,000/month.

Jan 1, 1999

By Kurt Egger, Emily A. Baker

Rehabilitation work at the Cameron Run Tunnels entailed the restoration of seven heavily deformed, approximately 69 m long, steel liner plate supported culverts through a CSX Railroad embankment near Alexandria, Virginia. A custom fabricated expander, equipped with four 200-ton hydraulic jacks on two expansion arms was used to push back the liner plates encroaching into the proposed tunnel profile and install the steel set support. In a second phase the tunnels were then lined with 16 cm of fiber reinforced shotcrete. Geotechnical instruments both in the tunnels and on the railroad embankment were used to monitor the effects of the rehabilitation work on the two CSX Railroad tracks above the tunnels. Freight and passenger trains were required to run uninterrupted and at maximum speeds throughout construction.

Jan 1, 2003

On my arrival in New York after the Russian examinations John D. Ryan, president of Anaconda, asked me what my plans were. I told him I wanted to be useful somehow in the World War that we had entered while I was away, but I did not know how. Ryan and Thayer told me that the new American Air Corps was gathering a group of executives, most of them young, to go to France as Army officers to help with the industrial side of our aviation activities. This would include construction of military airports, maintenance, and supply for our rapidly growing Air Corps. They thought I might be accepted in this group of about 30. It seemed to be just what I wanted, and I put in my application at once. My application was accepted about three weeks later and I was told to come to Washington to take physical and other tests and to meet others of the group. I liked them. They were a cross section of competent American manufacturers, bankers, automobile executives, and merchants. I was the only miner. I had many discussions in the days in Washington with members of our organization and others I knew who were going into war service. Attitudes were very different from those 55 years later. There was no discussion as to whether war was right or wrong. We were in it and must do all we could to help. At the same time there was a holdover from the days when, at least for the elite, war was high adventure. Even the most high-minded did not then realize that war is a horrible form of wholesale murder and, in 1917, it would have been treason to suggest this. I had two weeks before our industrial group was to start work which gave me time for a hurried trip to Berkeley where Dorothy and I announced our engagement.

Jan 1, 1976

By S. E. Phifer

The Haile gold mine was the largest gold producer east of the Mississippi River before 1942. It was the first gold mine in the Southeast to reopen following deregulation of the gold price by the United States Government. The Haile mine was also the first gold mine in the Southeast to use heap leaching and carbon recovery for gold production. Current production involves mining and heap leaching about 1.8 kt/d (1600 stpd). Carbon is used as a recovery medium. Due to the clay and excessive fines in the oxidized ore, agglomeration using portland cement is required before leaching. Agglomerated ore ranges in screen size from 50 mm (2 in.) to less than 75 µm (200 mesh). The agglomerating step combined with certain other conditions has enabled Piedmont Mining Co. to achieve recoveries of about 90% or better.

Jan 1, 1987

By Gary Bennethum, L. Courtland Lee

INTRODUCTION For any identified mineral resource to qualify as a minable reserve, it must contain legally and economically extractable mineral at the time of determination. As competition for land has increased, the legal complexities have more than kept pace, frequently becoming the most important determinant in mineral exploration and development projects. Rarely will developers of a project avoid having to obtain numerous federal, state, and/or local permits while acquiring the necessary legal permission to begin mining. Each site must be selected carefully, not only for economic feasibility, but also for legal feasibility. Although it is impossible to present site-specific solutions for all potential underground developments, certain generalizations may be applied to specific land categories, particularly federally owned land. Such federally owned land includes more than 33% of the land area of the United States and many of the areas potentially attractive for future development. State and local restrictions affect a large portion of the nonfederal land, and those restrictions are equally important even though their diversity and current status require more regional study than can be provided herein (the list of references include sources of additional information). Each potential mining site requires a title search of the land status to determine the land ownership and the conditions affecting development. In addition, appropriate data concerning the mineralogic and economic potentials of an area must be collected. As listed in Table 1, many sources of public information are avail- able to aid potential developers. Fig. 1 illustrates a typical federal master title plat. HISTORICAL PERSPECTIVE The settlement of the United States reflects a fascinating history of public-land laws and subsequent mineral-disposal laws. Most of the statutes of the eighteenth and nineteenth centuries sought to dispose of land for the purpose of generating revenue to the federal government. The underlying need for general revenue contributed directly to numerous and often conflicting land policies. More recently, diverse federal programs such as environmental legislation have transcended the need for revenue in forming the framework that determines who has power over mineral developments and where those developments can take place. In 1812, the General Land Office was established under the Treasury Dept. At that time, English common law prevailed, entitling the owner of the surface to whatever was contained within the surface boundaries from the surface to the center of the earth. Unless a distinct title separated the mineral estate, it was included in the surface-land ownership. However, gold and silver were the property of the crown and were controlled by sovereign prerogative. Early state legislation on the subject of mines and minerals may be classified as legislation providing for the sale of state lands with a reservation of the minerals and legislation recognizing or asserting the sovereign prerogative for precious metals. In 1781, a Pennsylvania statute reserved 20% of all gold and silver ore for the use of the commonwealth. Thomas Jefferson suggested that a portion of all gold and silver be retained by the federal government. These early rules affecting land in the eastern states, now privately held, have been re- pealed, declared obsolete, or largely ignored. Federal legislation prior to 1848 and affecting mining may be classified as legislation reserving the minerals to the United States and legislation authorizing the disposition of reserved minerals by sale, lease, or grant. With many modifications, these basic policies remain in effect at the present time. A 1796 act provided for the sale of the Northwest Territory and for the establishment of the present system of rectangular survey for public lands. The Lake Superior copper region was the scene of "wild and baseless excitement in 1837" when the attorney general concluded that the president had the power to lease lands in Wisconsin; this opinion soon was overturned by another attorney general. By 1846, Congress had passed legislation authorizing the president to sell reserved lead mines "as soon as practicable" since the system of granting Leases had proved to be unprofitable to both the government and the lessees, many of whom refused to pay the rent. The general practice of early federal Legislation was to make a distinction between mineral lands and other lands, deal with them separately, and generally withhold mineral lands from disposal except through special legislation dealing with particular land. In 1848, following the treaty of Guadalupe Hidalgo, a vast land area was ceded to the United States by Mexico. This area included the present states of California, Nevada, and Utah, as well as portions of Arizona. Colorado, New Mexico, and Wyoming. This abolished the Mexican laws and customs relating to mining and preceded the adoption of the miners' own rules and customs. The adoption of those rules and customs followed a hard-fought battle between western congressmen and the eastern establishment. The western congressmen advocated adopting local customs through a location patent system, while the eastern establishment, particularly in Ohio and Indiana, favored an all- leasing system to pay off Civil War debts. The first mining law was passed in 1869 as an amendment to an act granting right-of-way to ditch land owners, and it was followed by the 1872 Mining Law. Precedent was established for the first categories of protected lands in the opening words of this act, which included the phrase "all unreserved" lands. Reserved lands subsequently defined included military and Indian reservations and were excluded from location since they were determined to be reserved lands. However, the overriding purpose of the mining laws was to settle the western lands and generate revenues for the federal

Jan 1, 1982

By J. C. Yingling, R. J. Sweigard, P. W. Conrad, J. M. Ringe, D. H. Graves

Much of the land reclaimed since enactment of the 1977 Surface Mining Control and Reclamation Act is overcompacted. Research has shown that excessive compaction in replaced growing media is detrimental to the establishment of trees. If trees are to be grown on reclaimed surface mined sites, something must be done to alleviate this excessive compaction. Dry bulk density and penetration resistance are two soil parameters that can be used to indicate the level of compaction in reclaimed growing media. The University of Kentucky developed test cells on reclaimed areas at a surface mine in eastern Kentucky to determine the impact of tillage (ripping) on soil compaction and tree survival rate. The ripping methods being evaluated include shallow tillage using conventional farm equipment and deep tillage using a dozer with a ripping arm. Each test cell was planted with various species of trees, and for the first two years of tree growth, data were collected at these test cells for soil dry bulk density, penetration depth and resistance, and survival rate of trees. These data were statistically correlated to determine how ripping affects the relationship between soil compaction and tree survival rate.

Jan 1, 2003

By J. P. Barbosa, R. V. V. Araújo, R. B. E. Trindade

Bromide stabilizes the auric or aurous ion by forming a stable complex in acidic aqueous solution. The oxidizing agent normally used for the process is bromine, which is a corrosive liquid with high vapour pressure. This is, in fact, the main reason why it has not found acceptance yet as an industrial oxidant for gold. Ferric ion with hydrogen peroxide and/or sodium hypochlorite have already proved to be effective oxidants for the dissolution of gold from a rotating disc in a bromide-containing aqueous solution. In the present work, preliminary tests with four selected ore samples were tested to evaluate the dissolution of gold with the same system already tested with the rotating disc (Br-/Fe3+/H2o2/NaCIO). Compared to the conventional cyanidation, results were superior in one instance only. The major obstacle seems to be the maintenance of a suitable potential to allow the complex formation. However, the studied system may be interesting, is in some situations it may yield better results than conventional cyanidation; therefore, further investigation seems to be worth doing.

Jan 1, 1995

By J. M. Velazquez, J. H. Meza Viveros

This paper describes some of the parameters and technologies used at the Mexicana de Cobre smelter, and discusses the principal design parameters and new technologies that are being implemented in a smelter-expansion project designed to increase the production capacity of anode copper from 180 to 300 kt/year (200 to 330,000 stpy). In addition, some parallel projects under construction in the smelter plant are described.

Jan 1, 1999

By John L. Burnett

Field criteria are needed to help the prospector recognize a potentially expansible shale, clay, or slate. Certain criteria have proven useful in California even though the physical-chemical mechanisms of expansion are not thoroughly understood. Three conditions must be satisfied before expansion can take place, The raw material must partially fuse at a low temperature (1800-2000°F.), Concurrently a gas must form. The raw material must be sufficiently impermeable to trap the gas within the particle. Low temperature melting, which is controlled by bulk chemical composition, is difficult to assess in the field but most common shale, clay, and slate is suitable in this respect, The presence of organic carbon, the most common source of an expanding gas, is indicated by dark color of the rock, A large proportion of clay-sized particles promotes impermeability; fine grain-size is indicated by conchoidal fracture, The shape of the expanded particle is commonly indicated by the texture of the raw material. Rocks with well-developed slatey cleavage produce accordion-shaped particles; massive rocks tend to form rounded particles. Undesirable materials commonly present with expansible shale include: weathered shale; sandstone and other coarse-grained sediments; and limestone, Weathering, which is indicated by color, reduces or eliminates expansion; therefore, surface samples seldom are representative of the shale found at depth. Sandstone does not expand and will increase the average weight of the finished product, Limestone or particles of carbonate minerals can be actively harmful because they are converted to free lime (CaO) during the firing process, If free lime is present in concrete, hydration will cause expansion of the lime particles which result in surficial ?popouts.?

Jan 1, 1963

By G. E. Slagel

On August 3, 1987, a hearing was held by the House Subcommittee on Energy and the Environment to commemorate the tenth anniversary of the Surface Mining Control and Reclamation Act (SMCRA). Four panels of environmental/citizen group representatives went before the Subcommittee to report on the state of affairs (from their perspective) of the coal industry and the Office of Surface Mining, Reclamation and Enforcement (OSMRE) As expected, these groups had little positive news to report and continued to focus on glaring deficiencies within the surface mining program. They indicated that gross abuse of SMCRA has continued over the past ten years and the states have performed poorly. Congressman Udall's opening comments perhaps best characterized the mood of the group with his statement that "The Act has not accomplished what I or the people of the coalfields had hoped." and " ? a segment of the coal industry has continued in its bitter and implacable opposition to the most basic of environmental controls."

Jan 1, 1988