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By E. J. Owen, A. Appah, I. C. Sanchez, K. T. Stafford, N. Hurtig, R. Otoo, N. A. Iverson, S. A. Moses, V. T. McLemore

New Mexico lies at the eastern edge of one of the world’s great metal-bearing provinces hosting numerous Laramide and Paleogene mineral deposits. Southwestern New Mexico contains Laramide porphyry Cu (±Mo, Au) and Paleogene Mo-W deposits. Porphyry deposits are generally large, low-grade deposits containing Cu, Fe, Mo, Au sulfides (and other metal sulfides) associated with porphyritic intrusions and exhibit characteristic alteration styles. Porphyry deposits can also be spatially and temporally associated with skarn deposits and polymetallic veins. All of these deposits have the potential to host various critical minerals, including Cu, Zn, Bi, Co, Ni, rare earth elements (REE), Te, and W. Critical minerals may be found as substitutions within ore minerals or as separate mineral phases. These deposits are constrained using 40Ar/39Ar dating into three ore-producing magmatic pulses: 1) ~78–71 Ma Laramide pulse, 2) ~59–50 Ma, Laramide pulse, and 3) ~40–30 Ma Paleogene pulse. New and historic whole-rock geochemical data have highlighted areas with critical minerals potential that require further study.

Feb 1, 2025

By Shunji Sukizaki

Recently development of cheaper and cleaner energy sources has become a more important and urgent issue, because of the soaring crude oil price and environmental problems such as global warming. In this social context, to establish basic technologies and solve fundamental issues associated with environmental impact assessments, the Environmental Impact Assessment Group of the Research Consortium for Methane Hydrate Resources (MH21 research consortium) in Japan has conducted a number of research and development activities since FY2001. These activities include: 1) surveys of the marine environment that will form the basis of environmental impact assessments associated with methane hydrate development; 2) the development of core technologies to monitor deep-sea environments; 3) research of major issues related to environmental impact assessments; and 4) the development of numerical models to predict the deformation of seafloor sediments containing methane hydrates.

Jan 1, 2008

By H. Keith Henson

The purpose of this paper is to describe the possible application of two relatively new technologies: flat load cells, and improvement seeking computer programs (referred to in the literature as heuristic programs); to a very old problem, inventors control of ball mills. The combination of these two technologies seems most applicable to grate discharge mills operated closed circuit. It is possible that other applications such as controlling the inventory of autogeneous mills might also be found. Direct control of ball mill inventory has been the goal of a number of investigators over many years. Many patents and articles on the subject have claimed success, but operating installations are hard to locate. An excellent review of the advantages and problems of direct inventory control is contained in an article by Oswald and Ziegler (1). Figure 1 is a conventional representation of throughput vs. inventory with other factors such as slurry consistency and rock twee held constant. There are common sense, physical arguments? and experimental evidence supporting the existence of a unimodel curve of this twee? though direct measurement of the shape is difficult and how it moves as rock type changes is riot well known. Figure 2 represents the problem faced by all mass measurements of inventory, a tare weight of about 25 time the inventory mass. Worse yet, the tare is variable due to ball and liner wear and the Periodic addition of balls. The problem then breaks down into two parts: 1) obtaining enough mass

Jan 1, 1977

By Floyd L. Prestridge

A test of a solvent extraction (SX) pilot plant featuring electrostatic coalescence has been performed by C-E Natco at the United Nuclear uranium mill in Church Rock, New Mexico. Operating in parallel with the United Nuclear SX system, the C-E Natco electrostatic SX pilot plant exhibited comparable extraction efficiency to the United Nuclear system which utilizes conventional mixer-settlers. The C-E Natco pilot, however, operated at much higher liquid loading rates and exhibited less communication between the aqueous phases of the extraction and stripping circuits.

Jan 1, 1983

By Joseph M. Morrison

This paper offers a comprehensive solution to the problem of dust emissions at belt conveyor transfer points. It discusses details of enclosure design and presents a straightforward procedure for calculating required dust control exhaust volumes. Many design variables are taken into account which heretofore have been commonly ignored or inadequately considered. These include belt widths, belt speeds, enclosure openings, material flow rates, material bulk densities, material lump sizes, height of material fall, material temperature, and ambient air temperature. All of these quantities are handled by means of a "fill-in-the-blanks" type of calculation form which permits quick, reliable solutions by relative "non- experts".

Jan 1, 1970

By A. S. Kastrinos

There are many concepts of preventative maintenance. The basic objective of all maintenance organization, however, is the efficient (accomplishment and control of all) inspection, repair, overhaul, material and preventative maintenance functions necessary to maintain facilities and equipment in a condition that will meet operating requirements at a level consistent with low costs and high availability. To formulate a preventative maintenance program requires sound judgment and the ability to apply in a practical manner a system that meets Plant operation requirements, based upon organization, experience, conditions, design and historical data. A maintenance program must be divided into to categories consisting of: 1. Scheduled tasks to be accomplished at planned intervals. The objective of these tasks is to maintain reliability and prevent as much as possible abnormal failures. 2. Non-scheduled tasks that result from periodic reports and which can be scheduled to fit in conveniently with other routine work. The non-scheduled work items may include long-range preparation for lenghty shutdowns requiring Engineering and Shop services.

Jan 1, 1975

By Richard B. Berg

California was a major talc-producing State until the late 1980s when production from the deposits in the Death Valley area ceased because of a number of factors which included pressure to discontinue mining in and around Death Valley National Monument, and health concerns affecting markets for tremolitic talc. The states of Montana and Texas now account for slightly more than half of U.S. talc production. Deposits in an area encompassing southern Death Valley and extending east into the Kingston Range were formed by contact metamorphism of carbonate beds in the Precambrian Crystal Spring Formation next to Precambrian diabase sills. These deposits contain ore ranging from high-purity, fine-grained talc to platy, tremolitic talc with high brightness. Deposits of tremolitic talc and talc schist in the Silver Lake District in San Bernardino County resulted from metamorphism of Precambrian carbonate beds intruded by granitic plutons. Northeast in Esmeralda County, Nevada hydrothermal alteration related to Late Jurassic plutons caused talc replacement of Precambrian to Early Cambrian dolomite. A hydrothermal origin is also indicated for talc deposits in the lnyo Range just north of the Death Valley District where bodies of unusually pure talc occur in Paleozoic lime- stone near Jurassic granitic plutons. Talc is now mined from a deposit in the foothills of the Sierra Nevada Range southeast of Sacramento where quartz-mica schist of the Permian Calaveras Formation has been hydrothermally altered to talc. Replacement of magnesite of the Precambrian Allamoore Formation produced talc deposits mined in the Allamoore District of west Texas. This dark-gray talc of low iron content with carbon- aceous material and dolomite is ideally suited for use in ceramics where it makes a white product when fired. Small bodies of platy light-pink to white talc suitable for use as an extender in paint are also mined in this district. In the Llano District of central Texas talc has replaced impure carbonate rocks and serpentinite. All Montana talc production is from deposits in the southwestern part of the State that formed by Precambrian hydrothermal alteration of dolomitic marble. This alteration produced material with high purity that ranges from very fine-grained, massive talc to coarser grained, foliated talc. Markets include pitch control in paper, paint, cosmetics, ceramics, rubber and plastics. In southwestern and northeastern Oregon, talc has replaced serpentinite in the vicinity of Mesozoic plutons. Soapstone for carving is mined from a southwestern Oregon deposit. Deposits of similar origin occur in central and northwestern Washington.

Jan 1, 1995

By John B. Pate

In a recent issue of the Mining Congress Journal, J. L. Gilliland discussed the relationship of air quality criteria, standards, and regu¬lations (1). As he pointed out, The Secretary of the Department of Health, Education, and Welfare is charged with issuing "Air Quality Criteria" which are statements concerning the concentration-effects relationship of an air pollutant. These "criteria" provide the states with a basis for their air quality "standards," which may lead in turn to emission "regulations." He further cites a list of major factors described by the National Air Pollution Control Administration, which must be considered in developing criteria. These are: properties of pollution; responses; measurement methods; exposure parameters; and characteristics of receptors. Although we briefly discuss the first two items, the principal concern of this paper is with the third item, the methods of measurements. In attempting to define responses, it has proven surprisingly difficult to establish a clear-cut cause-effect relationship between air pollutants and impairment of health. It is perhaps not too surprising that the ecological approach currently in fashion seems to be a much more powerful tool in defining cause-effects relationships. Without belaboring the point, we would like to point out that establishing such cause-effect relationships have tremendous legal and financial implications e.g., consider the possible establishment of such a relationship between pollution and inadvertent weather modification.

Jan 1, 1970

Engineering programs usually do not provide sufficient opportunities for students to develop written communication skills. The responsibility for developing those skills is frequently delegated to the humanities faculty, who in a single technical writing course are supposed to transform engineering students into proficient communicators. A general template which was developed for report writing in our senior level capstone design courses is discussed. Students have improved their writing skills by using the template. The writing assignments have provided the students the opportunity to write and revise more technical reports that communicate their design.

Jan 1, 1995

By J. W. Leonard

Breakage, handling and treatment techniques that result in the placement of greater quantities of coal in fixed volume haulage units such as ships, railroad cars, trucks, mine cars, shuttle cars and scoops can do much to increase productivity by improving bulk density to reduce delivered cost, surprisingly enough, only in steel industry by-product coking has this subject been investigated and applied to practice, where as much as 20% or more productivity has been achieved. Research at UK Mining using popular coal mine loading cycle simulators shows that for typical Central Appalachian mining conditions a 10 to 20 percent gain in bulk density can produce a 15 to 30 percent increase in the loading cycle time of fixed volume shuttle-car/scoop based mining systems.

Jan 1, 1989

By A. I. Makhin, S. M. Sablukov, V. K. Sobolev, V. A. Larchenko, V. S. Shchukin

The kimberlites of northern Europe are related with a large crustal block having a northwest-southeast orientation. Kimberlites penetrate the Archean formations of crystalline basement, Late Proterozoic rocks, which are overlapped by Middle Carboniferous and younger deposits. The kimberlites bodies include pipes, dikes and sills of Upper Devonian age. Within the region, rocks of two magmatic series form diamond-bearing kimberlites. Aluminum rocks form a new type of diamond-bearing rock that is not found in other diamond provinces. Kimberlites of this region are characterized by highly developed deuteric alterations, a low content of associate minerals, the presence of two diamond generations and an increased content of jewelry-grade diamonds.

Jan 1, 1997

By J. M. Mutmansky

Introduction Since the Hardy Cross numerical algorithm was applied to the solution of mine ventilation networks, numerous developments have taken place in ventilation network analysis procedures. The Newton-Raphson method, the linear theory method and the second-order approximation method are three of the additional approaches that have been applied. The efficiency of a ventilation network analysis procedure depends not only on the method of solving the system of equations derived from ventilation networks but also on the method of deriving the equations through selection of the meshes. This paper investigates the impacts of three mesh selection methods on the efficiencies of four ventilation network procedures. The minimum-resistance spanning tree method is the most popular procedure for selecting meshes. The shortest-path method was suggested by Epp and Fowler (1970) for improvement of the Newton-Raphson method. The minimum-resistance-path method is suggested here as the third method of selecting meshes. The effects of these three methods on the Hardy Cross method, the Newton-Raphson method, the linear theory method and the second-order approximation method are analyzed in this paper. These network analysis methods have been summarized in the paper by Kim and Mutmansky (1991). Mesh selection methods A procedure for mine ventilation network solution based on mesh equations typically consists of two steps: • the mesh selection step and • the network solution step. The mesh selection step establishes a set of independent equations to solve the network. The resulting equations are nonlinear. One method of solving nonlinear equations is to linearize the equations and iteratively solve these linear equations. The four analysis methods previously discussed in this paper use this approach. The linear equations required for solution can be written in matrix form as: P•dQ = dF (1) where P is the pseudo-resistance matrix, Q is the quantity matrix, and F is the Jacobian matrix (Kim and Mutmansky, 1991). The efficiency of the solution method depends on the characteristics of the P matrix, which in turn depend on the method of selecting meshes. To understand the impacts of the mesh selection methods on the efficiency of the ventilation network analysis procedures, the characteristics of the P matrix must be understood first. The diagonal elements of the P matrix, m in number, are the sums of the pseudo-resistances of the branches contained in the m meshes necessary for solution. The off-diagonal elements are the sums of the pseudo-resistances of the branches shared by two meshes. For example, P12 (first row, second column element of the P matrix) is the sum of the pseudo-resistances of the branches common to mesh 1 and mesh 2. When solving the system of equations expressed in Eq. (1), three of the iterative procedures (the Newton-Raphson, the linear theory and the second-order approximation methods) use the direct factorization method (Burden and Faires, 1985) on the P matrix. When the direct factorization method is used, the computational efficiency is enhanced by larger diagonal elements and a sparser P matrix. Generally, the sparsity of the P matrix is more important than the size of the diagonal elements. There is no known mathematical method of predicting the efficiency of these procedures, but heuristic methods can be used to study the efficiency. The Hardy Cross algorithm applies the Gauss-Seidel method of splitting the P matrix and applies the Newton-Raphson procedure. The efficiency of the Hardy Cross method depends on the spectral radius of the matrix[[D-L]-1U], where D is the diagonal, L is the lower triangle and U is the upper triangle of the P matrix for the Newton-Raphson method (Ortega, 1972). The smaller the value of the spectral radius, the faster the convergence. As with the other three methods, larger diagonal elements and a sparser matrix aid in faster convergence. With the Hardy Cross method, however, the size of the diagonal elements is more important than the sparsity of the matrix. Remembering that each of the diagonal elements of the P matrix is the sum of the pseudo-resistances of the branches in a mesh and that each off-diagonal element is the sum of the pseudo-resistances of the branches shared by two different meshes, the following strategies can be used: • Avoid having branches with larger resistance values shared by multiple meshes. This increases the size of the diagonal elements and reduces the chance of off-diagonal elements being large.

Jan 1, 1993

By W. E. Benton

The name Perlite applies to both a hydrated volcanic glass containing from 2% to 5% combined water and to the lightweight material that is produced from expanding the sized volcanic glass. Upon heating, Perlite expands to about twenty times its original volume which results in a material of low density, low thermal conductivity, and high sound absorpt'ion. Perlite ore is mined by open pit methods and is crushed and sized to provide specific gradations for expanding into products used in acoustical tile, built- up roofing, filtration, lightweight concrete and horticultural applications, among others. In 1983, the U.S. production of crude Perlite came from 12 mines and 6 western states, with apparent consumption and production estimated to be about 6% lower than 1982. The average price per ton was slightly higher than in 1982.

Jan 1, 1984

By Harry R. Dahlberg

Heap leaching is discussed as a unit process. Five factors are identified as the principal elements that can be measured and/or controlled. These are: 1. Material Size 2. Volume of solution 3. Tonnage of heap 4. Time 5. Solution concentretion. The Rate of Extraction Curves obtained from an actual heap or column tests describes the economic viability of the unit process. By analysis of these curves and the five factors end their inter-relationship it is possible to determine how the extraction rate can be increased. The practice of leach and rest used by many operators is analyzed and shown on a hypothetical rate of extraction curve. The influence of the driving force of the hydrogen ion and ferric Lon as Lixivants and its effect on the rate of extraction curve is discussed.

Jan 1, 1979

By R. R. Godard

The practice of dust abatement or control is not new to any operation of United States Steel Corporation. This report will review those activities, past and present, within the five operating districts of United States Steel-Coal Operations with specific reference to mechanical and continuous mining, and including both the health and safety aspects of the problem. Obviously, the first principle of dust control is to inhibit its formation If this is not practical, steps may be taken to prevent its becoming airborne. Airborne dust control can be realized by either collecting it at the point of generation, diluting it with large volumes of air to reduce concentration, settling it by various means, or with reference to ignition hazard only, render it incombustible by neutralization with an inert material. These basic principles have been verified by the work of many, including the Bureau of Mines, U. S. Department of Interior, Bituminous Coal Research, Inc., and the Mining Research Establishment of the National Coal Board of Great Britain. Their application to every day mining problems is best illustrated by the following examples.

Jan 1, 1967

By Leo J. Miller

Sulphur deposits occur within the upper Salado and Rustler gypsum beds. The formation of a sulphur ore deposit requires large quantities of oil and /or gas, which must find a permeable pathway into the gypsum beds. The Permian beds weathered for 90 million years in an arid environment prior to the advent of a more humid climate at the beginning of the Cretaceous Period. The first Cretaceous rivers enlarged the sinkholes and caverns of the Karstified Permian terrain and deposited coarse conglomerates and sands into the subsurface gypsum beds. The resulting network of caverns and sinkholes, filled with permeable sediments, permitted the free flow of hydrocarbons through gypsum. All sinkholes and caverns infilled with Cretaceous sediments that have penetrated beds of gypsum are associated with sulphur deposits. The Castile gypsum lies directly upon the oil bearing Bell Canyon formation. Sinkholes and caverns filled with Cretaceous sediments occur in the lower Castile. Biogenic calcite and sulphur are adjacent to these sediments. However, faults assume the major role in generating the initial permeability, allowing hydrocarbons to penetrate the lower Castile gypsum. The largest faults are associated with biogenic calcite and sulphur for a distance of 250 meters up from the bottom of the Castile gypsum. It is apparent that two dynamic geological processes are generating permeability within the gypsum beds: (1) the Cretaceous sands decending with difficulty into gypsum and (2) the faults creating permeability in the lower Castile but losing energy through soft bed deformation in the overlying gypsum. Both of these sulphur ore controls are mappable, but another large sulphur deposit of the magnitude of the Culberson Sulphur Mine has yet to be discovered. It appears that massive sulphur deposits are associated with the largest scale examples of each system, that is (1) high densities of deep sinkholes and separately

Jan 1, 1992

By A. C. Alexander

Chevron Resources Company owns and operates an open pit phosphate mine and mill 11 miles north of Vernal, Utah. The plant currently produces 500,000 tons per year of concentrate and has the capacity to produce 750,000 tons per year. The operation is currently being expanded to 1,300,000 tons per year of concen¬trate in order to supply a new fertilizer plant being constructed by Chevron Chemical Company in Rock Springs, Wyoming. A 10-inch, 96-mile pipeline is being built to transport the concentrate from Vernal to Rock Springs. The present and expanded operation will be discussed. HISTORY In 1915, Harry Ratliffe staked nearly 15,000 acres of low to medium grade phosphate rock along the southern flank of the Uintah Mountains. This deposit became the largest privately owned phosphate deposit containing approximately 700 million tons of reserves. Initial development of the deposit began in 1958 by San Francisco Chemical, a joint venture between Stauffer Chemical Company and Mountain Copper Limited. In 1968, Stauffer Chemical Company bought out Mountain Copper Limited and became sole owner and operator. In 1981, Chevron Resources Company bought the property from Stauffer and has operated the mining and milling operations since.

Jan 1, 1985

By Bernie W. Martin, Jesus Schabib

The East Side Access (ESA) Project in New York will be the largest tunneling project ever undertaken by a US railroad. The objective of the ESA project is to connect the Long Island Rail Road (LIRR) Main Line and Port Washington Line in Queens to Grand Central Terminal in Manhattan. The Project is divided into two distinctive segments: Manhattan and Queens. The Queens segment is subdivided into two major components; cut and cover tunnel construction and bored tunnels. The bored tunnels in Queens consist of five tunnels driven from a launch shaft and traverse a railway storage yard, Sunnyside Yard and terminate under the multitrack mainlines of Amtrak and LIRR at portals in the heart of Harold Interlocking where1200 trains pass every day. The soil consists of remnants of glacial till moraines and of outwash and till deposits of inter layered gravel and fines, with the occasional boulders and cobbles and with a high ground water table. It is anticipated that a Pressurized Face Machine, either slurry or Earth Pressure Balance equipped with roller disks to mine the boulders encountered as well as the mixed face, will be used to mine the tunnels. One pass reinforced concrete gasket bolted liner will be used. The cut and cover construction consists of an approximately 21.3 m (70 feet) deep excavation supported by slurry walls and jet grout columns. The slurry walls, in combination with overlapping jet grouted columns, are installed to top of rock forming a closed bathtub to control external groundwater drawdown. Maintaining the groundwater level near its original elevation is of paramount importance in order to prevent undesirable settlements and migration of groundwater that could be contaminated. Mitigation measures to prevent the migration of nearby plums are contemplated for all types of tunneling and excavation work in this site of the ESA project.

Jan 1, 2001

By D. M. Stephens

Feeder-Breakers were an unknown but much needed piece of machinery when U. S. underground coal mines started converting to more efficient belt haulage of the R.O.M. coal as compared to conventional methods that the 1950's offered. These simple electromechanical machines offered efficiencies in three areas: (1) they contained a surge hopper that allowed a "load' of coal to be dumped without delay; (2) this material was fed horizontally by a drag chain conveyor into a rotating carbide pick breaker that broke all oversize material into a beltable size, and (3) it fed this broken material onto the belt conveyor at a rate conducive to its design. Since its introduction, the Feeder-Breaker has evolved from that first low capacity, low breaking force machine to today's model capable of breaking materials up to 5 MOHS in hardness and having throughput capabilities exceeding 3,000 TPH with availability in the 90 percentiles.

Jan 1, 1985

By R. A. Halatchev

Historically two basic approaches of production sequencing have been formed in the theory of open pit mine design. The first approach implements a technological discretization of the pit space within the ultimate pit outlines where the minimum working width is the limiting technological factor. The second approach uses a pseudo-economic discretization based on the implementation of analytical methods for designing intermediate/ultimate pit outlines and the concept of pit shells generation. The paper offers an elaborate analysis of both approaches used currently for discretization of the geological medium into working benches and modelling the working zone of open pit mine. The analysis is extended with a new vision for unification of the mining systems in open pit mine design under the form of a classification. A comparison of the approaches is provided to illustrate their advantages and disadvantages with regard to the implementation of the principle of waste deferment as one of the main principles of mine planning that exploits the time effect of money.

Jan 1, 2003