Search Documents

By Bob Rautenberg, Luminita Calin

The Tunnel and Reservoir Plan (TARP), commonly known as the Deep Tunnel Project, was developed by the Metropolitan Water Reclamation District of Greater Chicago as a two-phase solution to the problem of waterway pollution and basement flooding due to sewer system backups created by the combined sewer overflows. With only one contract left before completion of the Phase I tunnels—the 12.4 km(7.7 mi.) long Little Calumet leg—the pollution control phase of the 175.7 km(109.2 mi.) long system will be 93% complete, once the Torrence Avenue tunnel project comes to an end. This paper describes the Torrence Avenue tunnel project, currently under construction by the joint venture of Kenny (Sponsor) / Kiewit / Shea. Mining of the10.4 km (34,151 feet) long and 8.3 m (27'-4") diameter mainline tunnel was completed in a record thirty-one-weeks period and the concrete lining is nearing completion. Details on the complete muck handling system, numerous mining and concrete lining records will be given.

Jan 1, 2001

By W. M. Shaver, R. Letourneau, W. R. Dengler

Dynatec Mining Limited contracted to sink a 1500 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.5 ft) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (15 ft.) diameter double-drum hoist to sink the shaft with 12.5 tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1991

By L. M. English

When plotted as head vs. volume, fan curves start high and decrease in head with increasing volume while mine head curves start low and rise with increasing volume. Their intersection is the system operating point But wait a minute: Isn't head loss a negative number, a debit? And isn't fan head an energy addition, a credit? This, as every ventilation instructor knows, is often a stumbling block to student or audience comprehension. It is possible to use the intuitively correct curves -pressure losses as negative values and energy additions as positive values -and still obtain the correct operating point: adding the two curves produces a third curve that intersects the x-axis at the operating point, the point at \\tIich the fan energy input exactly matches air circulation energy loss. Using this technique also makes it easier to account for outside influences on the system, such as natural ventilating pressure; with the standard approach it is quite easy to add or subtract such influences to the wrong curve. This approach can be extended to the graphical solution of any series/parallel circuit or ventilation net\wrk. The results are the same, and the approach is logically consistent and less confusing.

Jan 1, 1997

By J. Kalliokoski

As part of a funded project we have completed a comparative literature survey of the US regional Proterozoic geology. For our com¬parative study model we used the geological settings of the very large pitchblende deposits in Saskatchewan, Canada and the Northern Terri¬tory of Australia. These occur in a variety of Archean and Lower Proterozoic host rocks, at and below a regional unconformity that is capped by subhorizontal Middle to Upper Proterozoic conti¬nental sedimentary rocks. We find that there have been recorded in some parts of the US similar unconformable sequences of Middle to Upper Proterozoic continental sedimentary rocks that overlie older basement rocks.

Jan 1, 1979

By Terry Ramsey, N. Finkelstein

INTRODUCTION The Cyprus Pima Mine is located 20 miles southwest of Tucson, Arizona and about fifty miles north of the Mexican border. The Cyprus Pima orebody was discovered in 1950. Feasibility studies were begun in 1952 employing underground development. Economic studies showed open pit operations to be feasible and stripping of overburden was begun in late 1955. The first ore was reached in October of 1956. A 3,000 tpd (tons per day) concentrator was completed and began operation January 1, 1957. From these beginnings, Cyprus Pima Mining Company has expanded into a plant processing approximately 54,000 to 56,000 tpd. Four expansions were required to bring the plant up to its present capacity. Each expansion incorporated what had been learned in previous operation of the plant. The first expansion was completed in August of 1963 doubling design capacity to 6,000 tpd. In reality, because of softer than average ore, capacity was closer to 8,000 tpd. Expansion I1 was completed in July 1966 bringing design capacity to 18,000 tpd. Expansion I11 followed immediately. Completed in the summer of 1967, this expansion increased the design capacity to 30,000 tpd. The actual dry tonnage of this portion of the operation in 1974 averaged 38,400 tpd, again, primarily as the result of treating softer than average ore. The latest expansion (Expansion IV), completed in December 1971 and utilizing a semi-autogenous grinding circuit, is located in a separate building (Mill 11) approximately 200 yards southeast of the original mill (Mill I). Expansion IV was designed for 14,000 tpd, but after circuit modifications, averaged 16,500 tpd in 1974.

Jan 1, 1976

By Robert Smith

Deposits are global, said Barrick Gold's Smith. This means that the mineral industry, by necessity, is global. "Manufacturers have considerable freedom to decide exactly where they wish to produce whatever it is that they sell," he said. "What we sell, on the other hand, must be produced where nature chose to lay it down. The question is not so much, whether to go global, as when to do it and how to go about it." The timing of international expansion depends on external factors, often political, Smith said, and on internal ones that relate to the company's size and stage of development. "In deciding how to expand, a company is largely deciding how to adapt its existing business strategy to activity on the world stage," he said Barrick entered 1997 with 1.58 kt (51 million oz) of reserves, Smith said, annual production of 93.3 t (3 mil- lion oz) and cash flow of $463 million. Reserves in- creased 40% in 1996 and production will begin to rise again significantly in 1999. "We believe our fundamental strategy is responsible for our early development and subsequent success," he said. Barrick entered the gold-mining industry in 1983. Its corporate mandate was to create shareholder value, Smith said. From the beginning, the company took a different approach - businesslike, entrepreneurial, strategic and focused. "Many mining companies start out with a technical team and develop business and financial expertise thereafter," Smith said. "In 1983, Barrick had the business people, and then moved into mining." First, it acquired part interest in two small operations, one in Alaska and one in Ontario. Then, in 1984, it merged with Camflo Mines, which operated a low-cost underground operation in Quebec.

Jan 1, 1997

By V. G. Medina

The 15 000 t/d La Coipa mine initiated operation in July of 1991. The complex consists of a conventional, open-pit mining operation and a mill employing cyanide leaching with Merrill-Crowe gold and silver recovery. The process plant includes a primary crushing circuit, a 15,000 t (live) covered stockpile, a semi-autogenous mill/ball mill/crusher or SABC grinding circuit, a leach circuit, a belt filtration/washing circuit, a zinc precipitation circuit and a "dry" tailing disposal system. The process plant is described in detail with major design considerations used in the selection of the processes and equipment. The unique methodology employed in the disposal of the filtered tailings is also described.

Jan 1, 1992

By P. Raffinot, C. H. G. Bushell, S. Hodgson, E. F. Milner, H. J. Bosshardt, N. Draper, D. E. Pickett, Edwin T. McKnight, J. Prieto

Zinc ranks third and lead fourth in world nonferrous metal conumption. In 1972 the free world consumed 3,333,000 mt of refined lead and 4,422,000 mt of refined zinc. The lead tonnage was divided into the following end uses: storage batteries (42%), lead allows (7%), pigments and chemicals (11%), cable sheathing (9%), gasoline additives (13%), pipes and sheets (8%), and miscellaneous uses (10%). The corresponding distribution of zinc uses in 1972 was galvanizing (39%), die casting (26%), brass (15%), rolled zinc (8%), oxide excluding American Process zinc made directly from concentrate (6%), and other uses (6%). The pattern of usage of lead and zinc varies considerably from country to country. During 1972 in the USA 49% of refined lead was consumed in storage batteries, 19% in gasoline additives, and only 3% in cable sheathing, whereas in the United Kingdom 28% of the lead was consumed in batteries, 14% in cable sheathing, and 14% in gasoline additives. For zinc the major US uses were die casting (41%) and galvanizing (37%), with about 3% consumed as rolled zinc; corresponding usages in the same applications in France were 12, 28 and 28% and in Australia 12, 67, and 3%, respectively. The outstanding resistance of lead to corrosion, its density, and

Jan 1, 1985

By W. S. Fyfe

Gold is mobilized or made soluble under all crustal conditions given appropriate fluid chemistry with molecules which complex gold. In the surface environment chloride, thiosulphate and a host of organics may mobilize gold. In the epithermal range bisulphide appears effective as shown by the classic studies in the Taupo volcanic zone of New Zealand. In the high grade metamorphic to igneous ranges little is know but it appears that gas molecules in the system CO2 -CO-H20-S-C1 can do the job. Precipitation may occur by changes in P-T-EL-pH or boiling where such changes influence the liquid concentration. Of the known regimes information is good for epithermal systems, poor for surface lateritic environments, inadequate for high-T systems. Gold is often concentrated in bio-systems both living and dead. The influence of biosystems is little appreciated. There is a great potential for the discovery of new types of gold deposits and in particular, gold in weathering environments, gold in very high-T environments, gold in strike-slip faults and thrust regimes, and gold as a by-product in materials like coal and other organic debris. By the year 2500 we may find our noble metal resources in the asteroids.

Jan 1, 1987

By Andrew J. Petruska, Rik Banerjee

This study explores implementing a machine learningbased system to generate a 3D surface repre- sentation of the roof and support straps in the mine. Event cameras have been chosen for their performance in high-dynamic-range lighting conditions and for their low latency. To enable automated drilling and bolting, 3D vision using eventbased cameras has been developed. A ground-truth set is created using two, time-synced event cameras and a LiDAR camera. These sensors are used to construct a ground-truth dataset of corresponding event- camera images and surface maps from the LiDAR. The network is tested with stereopairs of event images and produces a depth image with ±5 mm RMS error on average across 1000 test images.

Feb 1, 2024

By K. N. Han, M. C. Fuerstenau, T. B. Onlin

A mathematical model describing the concentration profile of fine particles in the axial direction in liquid fluidized beds has been developed for the removal of fine particles. A forward finite differentiation technique has been used to solve a continuity equation with a source term to predict the concentration profile and, hence the recovery as a function of time. With the aid of experimental results obtained using a fluidized bed of 3-cm diam, dimensionless parameters were identified. These parameters were used to predict the concentration profile of fine particles in fluidized beds of larger sizes. Four different sizes of fluidized beds, namely, 1.3, 3.0, 4.0, and 7.5 cm in diam, were used in this investigation. The amounts of bed particles used included 4, 8, 16, 24, 59, and 120 g, and the size of bed particles were 48x100, 100x150 and 150x200 mesh.

Jan 1, 1987

By Donald C. Moore

Asamera Minerals Cannan Mine has been producing a 170 g gold/tonne (5 oz gold/ton) siliciaus flotation concentrate since July 1985. Flotation concentrate is shipped to a smelter for gold recovery. Numerous processes have been investigated to economically produce bullion on site. This paper describes the laboratory and pilot plant test results of a bacterial assisted oxidation of the refractory minerals. Economic comparisons with autoclaving and roasting processes are included.

Jan 1, 1989

By Ted Budd, Vladimir Goubanov

The East Central Interceptor Sewer, commonly known as the ECIS Project, is the largest public works construction project awarded by the City of Los Angeles. The complexity of this $240 million project, together with the challenge created by the mandated 1,000 calendar days for construction completion, make this project a major interest for the tunneling industry. This paper will describe the ECIS tunnel project, currently under construction by the Joint Venture of Kenny (Sponsor) / Shea / Traylor / Frontier-Kemper. Mining of the18.5 km (about 11 miles) long and 4.7 m (15ft-4in) diameter tunnel is underway with four Tunnel Boring Machines mining at the same time. Details on the mining machines, muck handling systems, innovative construction sequence, together with mining progress will be given.

Jan 1, 2003

By Nasri Munfah

Long Island Rail Road’s (LIRR) service to New York City is limited to Penn Station on the West Side of Manhattan, which is operating at its practical capacity for the commuter railroad. This situation imposes serious considerations for future growth and limits the destination of many Long Island commuters. The East Side Access Project will provide a connection of the LIRR to the landmark Grand Central Terminal (GCT)on the East Side of Manhattan. The construction of the connection will require significant tunneling and underground work utilizing a variety of construction techniques. In Queens, the connection will require five soft ground tunnels using pressurized face tunnel boring machine. In Manhattan, the connection will require a series of rock tunnels and caverns connecting to two deep large station caverns under GCT to accommodate eight tracks with four platforms in a stacked configuration. The caverns housing train rooms are connected to the lower level of GCT where a large concourse will be provided. With a budget of $4.3 Billion, The East Side Access Project is the largest transportation project ever undertaken in New York City. This paper provides an overview of the project, discusses its environmental and the engineering challenges, and provides an insight into the design development to date.

Jan 1, 2001

I reached New York at the start of my second South American adventure on Jan. 9, 1916. In the Anaconda office I found that we were not to take the steamer for two weeks which gave me time to study reports on Potrerillos and Corocoro. Reno Sales, whom I had met in Butte only casually, was to go with us to South America. Though he was only a little older than I, he was already an unquestioned leader of our profession, and we became and remained good friends. William Braden was in New York and would return to Santiago with us. Tom Hamilton would also be returning from a vacation. Leighton Stewart, a young engineer who was to work for Braden, was going on the steamer with us, taking along his wife. And of course Dr. Ricketts would go along. He had just become engaged to John Greenway's half sister, Kate Greenway, and in order not to be away from her longer than was necessary, he did not reach New York until a day before we sailed. This made eight of us who would be in the party. We were to go to Corocoro first, as Braden had taken an option on the Chilean company there. Development was already under way. As reports came in by mail we tried to get as good an idea of the property as we could before the actual examination. Mr. Thayer "put us up" at India House, one of the best lunch clubs in New York, and Reno and I ate our lunches there almost every day. Thayer, Braden, and Cornelius Kelley, who was to succeed Mr. Ryan as president of Anaconda, joined us when they could. At the lunches they told us about the under- ground war in Butte a few years earlier. When I wrote my chapter on the Butte wars in Romantic Copper more than 15 years later I could not help being biased a bit by my friends, all of whom were on the Anaconda side. But their opponents in the Clark and Heinze camp were just as biased in their comments on my book.

Jan 1, 1976

By Corby G. Anderson, Sheikh Abdul Rezan Sheikh Abdul Hamid, Sanjith Udayakumar, Ahmad Fauzi Mohd Noor, Teuku Andika Rama Putra

Chemical and mineralogical characterization of Malaysian monazite, a phosphate mineral, bearing rare earth elements separated from the tin tailings originated from Ipoh, Perak, Malaysia, was performed in this paper. The study aims to collect detailed information on the chemical composition, crystal phases, and microstructure of the mineral monazite concentrate that would aid to optimize the subsequent hydrometallurgical processes for high-efficient separation of thorium and other associated rare earth elements. A systematic characterization study of the concentrate was conducted using techniques such as optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). These techniques analyzed the morphological details on the surface, elemental analysis, and mineral association assessment and identified the surface functionalization groups. The bulk composition and the mineral phases in which the elements are present were studied by wavelength-dispersive X-ray fluorescence (WD-XRF) and X-ray diffraction (XRD) studies respectively. The XRF analysis confirmed the presence of Ce, La, Nd, Pr, and Y (rare earth oxides: REO’s ~ 60 wt.%) while thorium dioxide (ThO2) accounted for 7 wt.% of the total composition. Traces of Ca, K, Al, Fe, Ti, and Mn were also confirmed by SEM elemental mapping. The XRD results confirmed that the concentrate was primarily composed of monazite (Ce, La, Nd, Th (PO4)) along with minor impurity phases of quartz. Automated mineralogical analysis was used as a confirmatory tool to corroborate the preliminary evidences. Based on the particle size distribution analysis supported by SEM, the majority of monazite grains were found to be present in the size range of 170–210 μm. Strong bands of PO4 and SiO4 were observed in the IR spectra corresponding to the phospho-silicate matrix of the REE mineral.

By Isabel F. Barton, MarkD. Barton, Christian A. Rathkopf

Molybdenite is the world’s principal source of rhenium (Re), a critical element in multiple high-tech applications. However, the Re contents in molybdenite vary by orders of magnitude on scales ranging from single grains to whole deposits. In order to better understand the systematics of this variation and what geochemical factors control molybdenite Re concentration, and hence overall Re resources, we examine global patterns in molybdenite Re contents through a compilation of > 3000 measurements of Re in molybdenite from > 700 mainly ore-bearing moderate- to high-temperature hydrothermal systems of different types. Our results are similar to but expand on those of earlier studies. Rhenium concentration in molybdenite has a lognormal distribution and varies systematically with type of geologic system, intrusive lithology, and Mo grade. The lowest-Re molybdenite occurs in greisens (geometric mean 1 ppm ± a multiplicative standard deviation of 9), quartz vein-hosted W-Sn deposits (2 ± 5 ppm), unmineralized granites and granodiorites (12 ± 8 ppm), intrusion-related deposits (24 ± 8 ppm), and porphyry W-Sn deposits (16 ± 11 ppm). Rhenium is most enriched in molybdenites from volcanic sublimates (23,800 ± 5 ppm), with skarn Fe and Au (560 ± 5 ppm and 540 ± 3 ppm respectively) and porphyry Cu and Cu-Au deposits next (470 ± 4 and 430 ± 7 ppm respectively). Among porphyries, skarns, and quartz vein-hosted deposits, Re is most highly concentrated in molybdenites from Cu and Au systems and its concentration decreases systematically through Cu-Mo, Mo, Sn, and W deposits. In nearly all cases, molybdenites from systems associated with intermediate igneous rocks contain more Re than molybdenites from systems of the same type with more felsic rock associations. The disparity between Re contents of molybdenite in felsic and intermediate systems is largest for porphyries, quartz vein-hosted, and skarn deposits and is near zero for subeconomic or barren granite and granodiorite Mo systems; felsic intrusion-related deposits have slightly higher molybdenite Re than their equivalents associated with intermediate intrusions. In most systems, molybdenite Re content does not correlate with metal grade, but may have an inverse correlation with Au grade in intrusion-related deposits (based on a small number of data points) and does exhibit a strong inverse correlation with deposit Mo grade. Dilution of Re through larger amounts (higher deposit grades) of molybdenite explains about 40% of this correlation, but the relative enrichment of Re in molybdenite from low-Mo deposits must also reflect some selective enrichment of Re/Mo in porphyry Cu systems compared to porphyry Mo systems. We found no evidence for secular increase or other systematic temporal variation in molybdenite Re content. The data regarding the use of molybdenite Re content as a proxy for mantle influence are ambiguous. Nearly all observed empirical correlations can be traced back to differences in redox state and sulfide concentration, the two geochemical factors identified here and by previous experimental work as the controlling influences on Re mobility under hydrothermal conditions. Hydrothermal systems with reducing conditions (W- and Sn-rich) tend to have low molybdenite Re even though compiled whole-rock data indicate that their source rocks have as much or more Re as those of more oxidized systems (e.g., Cu-rich). Vapor-phase exsolution, crustal assimilation, and mixing with external fluids may all enrich molybdenite Re concentrations in individual deposits and deposit types, but their extent and importance in overall hydrothermal concentration of Re is uncertain. Thus, it appears that the available molybdenite Re resource in an ore deposit largely depends on how the deposit’s redox and sulfidation conditions have varied over time and space during the timespan of hydrothermal activity. Oxidized, high-sulfide conditions tend to concentrate Re in molybdenite, whereas reducing conditions tend to leave Re dispersed at low concentrations in the bulk rock.

By R. B. Hoy, Stanley J. LeFond, Unni H. Rowell, K. Reckling, Derek G. Fullerton

In 1989 natural industrial diamonds counted for 55% of the world's natural diamond production. Australia is currently the leading producer (35%). Zaire is the second largest producer (19%). of what is primarily industrial grade rather than gem grade. Botswana (17%) is third, with the former USSR (15%) fourth, and the Republic of South Africa (8%) fifth. Diamonds are also mined in Angola, Namibia, the Ivory Coast, the Central African Republic, Ghana, Tanzania, Guinea, and other African countries. In the Western Hemisphere, Brazil is the principal producer, with some production from Venezuela and Guyana [(Fig. 1)]. A very small output of diamonds is mined today in India, which was the first source of commercial production. In the United States, efforts at commercial diamond mining have been confined to a small area near Murfreesboro, AR. The first diamond was found in a pipe there in 1906. Small scale trial mining has not, however, proved economical. Since diamonds were first discovered more than 2,000 years ago, only about 380 t have been mined. In order to obtain 1 g (5 metric carats) of diamonds, it is necessary to remove and process approximately 25 t of rock. Recovering this small percentage involves a combination of highly developed techniques in mining and extremely sophisticated processes in diamond recovery. END USES Diamonds are used for two unrelated end uses: gem diamonds are jewels of great beauty, while industrial diamonds are essential materials of modem industry. Although imitation stones are substituted for the gem diamond, none of these matches its properties sufficiently well to offer real competition. Synthetic industrial diamonds are now of a quality and size that permit them to be substituted for natural diamonds in numerous industrial applications. For example, synthetic diamonds are available today in sizes up to 100 stones per carat (1.2 to 1.4 mm). In addition, polycrystalline synthetic diamond inserts, such as De Beers Syndite", General Electric's Compaxa and Stratapax", and Megadiamond's Megapax" have replaced natural diamonds in turning tools, mining and oil drilling bits, and dressing tool applications. Industrial Diamonds The diamond is by far the most important industrial abrasive. As recently as 50 years ago, consumption of industrial diamonds was less than that of gem diamonds, but since that time, industrial use has grown to a position of great dominance. During the six-year period 1929 to 1934, the material produced for industrial use amounted to about 74% by weight of the world's total output of diamonds. In 1989 the percentage of natural industrial diamonds mined in the world was 55%. When synthetic industrial diamonds are added to the natural industrial diamond figures, this percentage becomes 87% of total world diamond production including gems, near gems, industrial, and synthetic stones. The many uses responsible for these significant increases are dependent on the properties of the diamond, including hardness, cleavage, and parting, optical characteristics, presence of sharp points and edges, and capacity for taking and maintaining a high polish. The utilitarian role of the diamond was confined primarily to lapidary products until the industrial revolution, which created the first demand for diamond as an industrial tool. In 1777, a British inventor and instrument maker, Jesse Ramsden, used a diamond to cut a precision screw for an engine that he had invented. The first authentic description of industrial diamonds being set in a saw was recorded in 1854 by a Frenchman, Durnain. Eight years later a Swiss watchmaker, Jean Leschot, developed the first diamond drill bit for use in a hand operated machine, which was employed to drill blastholes in rock. In 1864, diamond bits were put to their severest test up to that time in the construction of the Mont Cenis Tunnel in the Alps. A few years later a steam-powered diamond drill with a speed of 30 rpm was able to penetrate rock at the modest rate of 0.3 m/hr. As the industrial revolution gained momentum on both sides of the Atlantic, metal replaced wood and machines replaced people. Thus the foundation was laid for precision engineering and the recognition of diamonds as an indispensable tool of industry. The next major demand for industrial diamonds came after World War I with the development of cemented carbide cutting tools. Diamond was found to be the most effective medium for finishing and grinding the new ultrahard metal. This discovery rapidly increased the demand for industrial diamonds. The availability of inexpensive diamond material inspired tremendous research into applications. By 1935, the first successful phenol-resin grinding wheel containing diamond had been marketed. Soon afterward, the metal-bonded and vitrified diamond wheels were produced, and, as the matrices and bonds that held the diamond grit in place began to improve, the popularity of diamond grinding wheels grew. The outbreak of World War II, and the accompanying increase in use of hard-metal tools in the munitions industry, increased the demand for industrial diamonds. Since about 1950, the development of ultrahard ceramics, semi- conductor materials, plastics, and exotic metal alloys has further consolidated the diamond's position as an indispensable tool of industry. Only diamond is hard enough to cut these superhard materials with the precision, speed, and economy that industry demands today. Special machines equipped with industrial diamonds are used to remove bumps from concrete runways and highways and to modify highway surfaces in order to prevent skid accidents. Many skids are caused by hydroplaning, a phenomenon that occurs when the roadway is wet. Tires mount a film of water and virtually lose contact with the road surface. Diamond machines cut neat, narrow

Jan 1, 1994

By N. Aouad

The deployment of large machinery for low cost, bulk surface mine production operations has resulted in high-impact shovel loading operations (HISLO). In extreme cases, shovels load large dump trucks with 100-ton (or more) passes generating high-impact forces under gravity. HISLO generates high-frequency shockwaves that cause severe truck vibrations exposing operators to whole body vibrations (WBV). Current research study in this area has established that the vibration levels affecting the operator?s seat, lower-back, lumbar and cervical regions fall within the extremely uncomfortable zone compared to the ISO 2631 comfort zone. These results pose health threats to truck operators over long-term exposure to these vibrations. In this paper, the authors will examine engineered solutions to mitigate these health threats.

Jan 1, 2011

By Alfred Jr. Petrick, William A. Vogely

INTRODUCTION The scope of mineral finance extends beyond the economic aspects of property evaluation to all of those activities involving acquisition and utilization of funds with an objective to optimize the value of the firm. It must, therefore, en- compass consideration of the overall financial goals of the firm, decisions involving external versus internal growth and domestic versus foreign investments, management of working cap- ital, efforts to minimize the cost of capital, and decisions with regards to the instruments of long- term debt and equity financing. The scope of this section is limited to considerations of special interest to the mineral or petroleum engineer, which include the following aspects of mineral finance: (1) The technical aspects of mineral or coal property or oil and gas reservoir evaluation which provide the basis for estimation and forecasting of revenues and costs. (2) Estimation and forecasting of costs and prices in a inflationary economic environment. (3) Calculation of cash flows which model .. , the investment in minerals, coal or oil, and gas. Such models require assumptions as to the timing of cash flows, escalation of capital and operating costs, base prices, and escalation, the tax regime, royalties, division of profits and the economic aspects of loans. (4) The role of discount rate in the economic analysis of an investment which requires consideration of the opportunity costs of the firm, cost of capital, risk premiums. (5) Risk analysis including application of the concepts of conditional net present value, expected value, and risk preference as well as the application of the techniques of sensitivity and simulation. (6) Selection of application criteria for in- vestment decision making. (7) Capital structure with particular reference to the effect of debt financing. (8) Consideration of sources of funds utilized by the minerals industries. (9) Long-range planning including portfolio analysis. This section is limited to principles, methodologies, and trends in mineral investment, finance, and long-range planning in the United States with a perspective from the year 1984. Consideration of the key concepts is supplemented by case examples of investment risk analysis and financial structure. Important factors affecting mineral investment evaluation during the 1980s include volatile metals prices, cost inflation, and the introduction of techniques requiring the computer and its capacity for improved technical and economic analysis into the hands of those who know most about the industry. The personal computer is replacing the calculator on the desk of the individual analyst and is rapidly becoming a required tool for the study of engineering and economics. Examples of change brought about by the micro-computer include greatly improved techniques of cost estimation, wider application of the computer for project analysis, computer graphics, reserve estimation, geostatistical analysis, mine design and other techniques that capitalize on the ability of the computer to handle

Jan 1, 1985