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By J. M. Cases

Diffuse - reflectance Fourier - transform infrared spectroscopy, Hallimond tube flotation and microelectrophoresis have been utilized to investigate the reactions involved in the adsorption-abstraction of K-amylxanthate on finely ground galena and pyrite. In order to work under well-controlled conditions both minerals were wet ground in a specially built laboratory stainless steel or iron mill. Four surface products were found to be formed on galena: monocoordinate lead xanthate, non-stoichiometric lead xanthate, dixanthogen, and amyl carbonate disulphide. Only dixanthogen was observed on pyrite after using stainless steel rods, while ferric iron xanthate was found when iron rods were utilized.

Jan 1, 1989

By Chris C. Sundberg, Ronald E. Heuer, Stanley L. Paul, Peter M. Douglass

Use of prestressed concrete cylinder pipe (PCCP) for pressure tunnel liners is gaining popularity with contractors, engineers, and owners. This paper presents loading considerations and a beam-spring computer model approach to tunnel liner analysis, together with ultimate strength (US) and service load (SL) procedures for liner design. The US procedure is best suited to check for adequate liner strength under extreme loading conditions. The SL procedure, based on conventional pipeline design practice, is considered more appropriate when addressing crack control and serviceability under normal working load conditions. Other design and construction considerations are discussed and a design example is presented.

Jan 1, 1987

By Z. Eisenstein, H. K. Heinz, F. M. Kuwajima

Due to its complex rheological behaviour, shotcrete induces a ground-structure interaction that differs significantly from other types of tunnel linings. For the same reason, the instrumentation of shotcrete linings presents special problems, particularly when it comes to estimating the stresses transferred to the lining during construction. The shotcrete characteristics which affect the stress distribution are initially discussed. Measurements obtained in a recent soft ground tunnel are also presented. The conclusions are aimed at introducing practical recommendations for the design of tunnels where shotcrete is used as initial and/or final support.

Jan 1, 1991

By E. G. Kelly, D. E. Walsh

The behavior of gold particles on a spiral was studied using radioactive gold tracers. The method allowed the effects of particle size, particle shape, pulp density, feed rate and splitter settings to be studied. Although the method has been successfully applied to other gravity concentrators, it was found that reliable results were more difficult to obtain on the spiral. However, these preliminary results show that, with suitable precautions, the technique is capable of providing valuable information, unobtainable from conventional studies, that could be used to better optimize spiral performance.

Jan 1, 1993

By Charles Merguerian

In medium- to high-grade metamorphic terrains such as found in New York City(NYC), rock mass texture and mineralogy are important factors in predicting TBM penetration destiny. Integration of data from over two decades of traditional field and tunnel mapping suggest that hard-rock TBM penetration in the NYC area depends upon textural, mineralogic, and structural control. The bedrock of NYC consists of many different lithologic units of varying age, composition, texture, and metamorphic grade including many varieties of intrusive rock. In addition, brittle faults of numerous orientations cut the polydeformed crystalline bedrock, producing zones of highly fractured and disturbed ground and high water inflows. Pre-bid compilation of published bedrock data, drill core analysis by geologists to establish lithologic and mineralogic trends, integrated surface geologic mapping along a proposed alignment, and targeted petrographic and geotechnical investigations to characterize the rock mass conditions together constitute an important prelude to successful subsurface bidding and tunneling. A carefully planned program of as-built geological mapping, structural analysis, fracture class mapping, and monitoring of machine performance data provide important information for adjusting to changed conditions. In complex terrains, a clear understanding of the structural geology of any proposed tunnel line is the simplest and most cost-effective method to mitigate losses encountered during TBM tunneling.

Jan 1, 2005

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

By Z. Kowalski

In the non-operational ?Górka? quarry, there are situated both a waste disposal site of an area of 6.7 ha, containing approximately 1 million ton wastes from high aluminium content materials (incl. about 400000 t of wastes from aluminum hydroxide production), and a pond of an area of roughly 3 ha, up to 15 m deep, with about 400000 m3 of polluted water and infiltrates from the disposal site mentioned. The basic problem related to the effluents in the Górka pond is both their high alkalinity (pH 12-13.4) and a variable analysis of pollutants whose level increases appreciably with the pond?s depth. The solution offered provides, first of all, remedial pumping and a treatment of effluents retained in the Górka reservoir. Effluents would be treated in a reverse osmosis plant according to a process verified so far on a quarter-commercial scale. The treatment process by-product, a brine solution (containing about 25% NaCl) whose amount may reach up to 100000 m3 might be supplied to the Debiensko Mine, which produces technological salt from salt-bearing mine waters. In parallel, an intake of underflows of infiltrates would be provided (previous geochemical identification) in order to take them away from the high aluminum site (by means of deep wells, and possibly girdling ditches). Such effluents would be subject to treatment. The successive stage is the utilization of approx. 50000 m3 of bottom slurry, left in the emptied reservoir, in the production of self-solidifying mixtures, which would be then used for sealing the bottom and the banks of the Górka reservoir. The empty and sealed reservoir would be filled up with a volume of approx. 600000 t of ashes, coming from coal burning in the thermal-electric power station. For the last stage, instead, is scheduled the rehabilitation of the entire waste disposal site in the Górka quarry. The site will be drained, covered with a leveling, sealing and rehabilitating layer, which will allow to introduce plants on the rehabilitated waste site. Later on, the area could be turned into a town park

Jan 1, 2006

By Pat Wilmoth, Joseph P. Gildner, Dan Nowak, Shane Yanagisawa, Don Z. Painter, Gordon F. Revey

Frontier/Traylor is presently completing construction of twin tunnels for the Tri-County Metropolitan Transit District of Oregon’s (Tri-Met) westside lightrail system. The tunnels are each 4,550 m (14,935 ft) in length and 6.48 m (21.29 ft) in diameter. The 1/3 of each tunnel was driven from the west portal using drill and blast methods and the remaining 2/3 was driven from the east portal using a TBM. The paper describes: The difficulties encountered by the TBM mining the weathered Columbia River Basalts. The execution of drill and blast work despite challenging ground conditions, stringent noise and vibrations specifications, and public relations problems. The excavation and lining of the Washington Park Station 79 m (260 ft) below the park zoo.

Jan 1, 1997

By E. Topuz

The objective of mine ventilation is to provide suitable environmental conditions in working places at an economical cost. Maintaining a stable air flow, i.e., a flow quantity and the direction, is of vital importance. In practice, however, air flow quantity in underground openings varies continuously. Therefore, the stability of air flow means relative stability that is the flow in a branch moves along a certain direction while the variation in air quantity stays within acceptable limits. Many underground mines have low stability of mine air flow because almost all types of ventilation systems involve complex diagonal branches through which air flow quantity and, more importantly, the air flow direction may change easily. This creates extremely hazardous, unstable conditions, especially during emergencies. This paper deals with the directional stability of air flows in underground mines in single or multiple fan systems. It examines the rules of directional changes of air flows in diagonal branches, and proposes a method of calculating the stability conditions. It provides a criterion that may be used in designing new mine ventilation systems to ensure a desired degree of stability or in improving the existing systems.

Jan 1, 1986

By Chee Theng

"It is not surprising that the most popular key takeaway from the Developing Diversity in Mining workshop (see box) held on the first day of the SME Arizona Conference in December was, “Have more parties!”The adage that mining professionals work hard and play hard was clearly demonstrated at the two-day conference in the JW Marriott Tucson Starr Pass Resort & Spa in Tucson, AZ. Nearly 550 participants, some of whom had left behind frigid temperatures and thick parkas in their hometowns, attended a full slate of technical sessions, shared industry experiences and knowledge, reconnected with buddies in the industry, and made strategic new contacts in the conference’s collegial environment, aided by the mild Arizona winter.To start off the technical sessions, John Mansanti, president and chief executive officer of Crystal Peak Minerals and 2017 SME president, entertained a packed lecture room with his keynote lecture on “Tariffs, Embargos, and Cartels ... Oh My! A Perspective on Potash.” Mansanti gave the audience the benefit of his more than 35 years of experience at companies including Barrick Gold, Newmont Mining Corp., Placer Dome, Freeport-McMoRan and Intrepid Potash, where he was senior vice president for operations, technology and strategy. At the luncheon, Justin Cross, general manager of Freeport-Mc- MoRan’s Bagdad operations, spoke on how the role of a leader in mining is transforming from one based on technical expertise to one based on the ability to collaborate, to lead and to adapt to changes in technologies and skill sets, in his talk on “Knowing When to Learn, When to Lead and When to Manage.”"

Feb 1, 2019

By Christopher J. Bise

INTRODUCTION Traditionally, the purpose of mine ventilation has been defined as diluting, rendering harmless, and sweeping away hazardous gases which may accumulate in the mine workings. In addition, the ventilation sys- tem must keep the mine air as close as possible to the composition of the outside air in order to provide a healthy environment for mineworkers and to prolong the useful life of mine equipment. When plans are being developed for opening a new mine, sound engineering dictates that a calculated estimate be made of both the maximum air quantity requirement and the accept- able mine pressure (head) loss related to the under- ground layout and projections. For efficient mine ventilation, the two problem areas that demand constant attention are (1) the control of fugitive air (through short circuiting or leakage) and (2) the provision of ample airway capacity. Fugitive air is that quantity of air which enters the mine but short-circuits the mine ventilation system through improperly constructed stoppings, doors, overcasts, etc.; it represents an investment in power consumption (to move the air by the fan) while providing little, if any, return on the investment. Typically, efficient mines are those that can deliver 50% of the air handled by their fans to the working faces. Paying close attention to a new mine's ventilation system at the outset can provide numerous benefits during the later stages of mine development. It has often been noted that the main cause of trouble in many mine ventilation systems can be found within a radius of 2500 ft from the fan installation. Ample airway capacity is essential to maintain the mine's head loss within manageable limits. Similar to an industrial ventilation setting, the mine's headings are the ductwork for the handling of air. The difference between normal industrial ventilation and mine ventilation is apparent when more capacity is needed; a plant can install new or larger ductwork, but it is difficult for a mine to install new entries or enlarge existing entries. Air velocities are usually maintained under 800 fpm to limit the stirring up of dust in the intakes. With this in mind, it is usually simple to estimate the number of entries required in the ventilation system. The problem that often arises, though, is when the system's capacity is overestimated and the required head loss to achieve the desired quantity is excessive. Experience has shown that problems are often encountered when the mine's condition requires much more than three inches of water gage to ventilate the mine on a day-to-day basis. Thus, if proper attention is not paid to these parameters in the preplanning and initial development of a new mine, it may take an extremely high water gage to achieve the ultimate quantity. This chapter will not delve deeply into the theory of mine ventilation; many other books have been writ- ten on that subject. Instead, the following sections will point out the important considerations that should take place before the development of a mine ventilation system, as they relate to normal industry practice. FUNDAMENTALS OF AIRFLOW Volume Versus Water Gage The common method of measuring ventilation pressure is in terms of inches of water gage (wg); one inch of water corresponds to a pressure of 5.2 psf (pounds per square foot). Further, airflow follows a square-law relationship between volumes and pressures where, as shown in the previous section, a doubling of quantity requires a quadrupling of pressure. Table 1 shows how heads and quantities are related. Using Table 1, it is readily apparent that, for the same mining conditions, an increase in pressure from one inch wg to three inches wg results in only 34,640 cfm when the initial quantity is 20,000 cfm. Pressure Losses Pressure losses in mine ventilation systems are caused by friction between the heading walls and the air stream and by shock losses due to abrupt changes of the air stream caused by obstructions. The common pressure-loss formula for mine ventilation is: [ ] where H is the pressure loss in inches of water gage, K is the coefficient of friction, L is the length of the airway in feet, 0 is the airway perimeter in feet, V is the air velocity in feet per minute, and A is the cross-sectional area of the airway in square feet. Table 2 lists the US Bureau of Mines schedule of friction factors (K) for mine airways. Recent research indicates that the values of K are slightly less for coal mines than those presented in the USBM Schedule, and Table 3 should be consulted in this instance. It should be

Jan 1, 1986

By Robert A. Jankowski, John J. McClelland, Charles Babbitt

The purpose of this study was to develop guidelines to enable mine operators to maximize longwall dust reductions, while optimizing the use of ventilating air and shearer water consumption. A recent investigation by Foster-Miller Incorporated, under a Bureau of Mines contract, quantified the effect of increased face airflow and shearer water supply on face dust concentrations. A 70 pct reduction in respirable dust levels was achieved at the shearer operator's position during tail-to-head cutting by an incremental increase in average face air velocity from 83.8 m/min (275 fpm) to 123.4 m/min (405 fpm), while holding shearer water consumption constant. A 60 pct reduction was achieved through an increase in shearer water pressure and flow from 9.1 kg/cm2 (130 psi) at 0.19 m3/min (50 gpm) to 19.7 kg/cm2 (280 psi) at 0.28 m3/min (75 gpm), holding airflow constant. The combined effects of increasing both parameters produced an 85 pct reduction. Optimal usage of ventilating air and shearer water consumption can be achieved by defining a "point of diminishing returns" above which further increases no longer reduce dust concentrations, proportionately .

Jan 1, 1987

From a vast army of workers to gargantuan machines to immense volumes of material being moved, almost everything about the Port of Miami Tunnel (POMT) project points to tunneling on a massive scale. Almost.The star of this underground and underwater show is a Herrenknecht tunnel boring machine (TBM,) nicknamed ?Harriet? by a local Girl Scout troop. With her 12.9-m- (42.3-ft-) diameter cutting head and a total length of 139 m (457 ft), Harriet is boring through thousands of cubic meters of clay, dirt and sand, which is often mixed with coral and other materials, to create two 1,280-m (4,200-ft) traf?c tunnels connecting Watson Island and the Port of Miami (Dodge Island) beneath Biscayne Bay, FL. But in the midst of all of the oversized equipment and machines, a strong contender for the best supporting nod goes to a relatively tiny machine: the Brokk 400. Bouygues Civil Works Florida crews are using the compact, remote-controlled and electric-powered machine to excavate five cross passages between the twin traffic tunnels. The pas-sages will be essential to the safety of people who drive their vehicles under the bay every day.

Sep 1, 2013

Reaction kinetics for gold dissolution in acid thiourea solutions were investigated using formamidine disulfide as an oxidant. For the conditions studied it appears that a surface reaction limits the rate of gold dissolution. The rate was found to be first order with respect to thiourea concentration and half order with respect to the concentration of formamidine disulfide; the apparent activation energy for the reaction was 10.40 kcal/mol (43.40 kJ/mol); and the reaction rate was independent of pH for the pH range 1.0 to 3.0.

Jan 1, 1999

By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991

By Richard L. Wedertz

Although the physical appearance of excavating equipment doesn't seem to have radically changed over the past decade, important changes within the products and an innovative attitude on the part of the engineer in his design approach is becoming increasingly evident. The new philosophy is to go beyond simple refinements of existing designs that simply produce a machine which further reduces overall cost per ton or per cubic yard of material moved and to do it more efficiently than ever before. Standard ideas and preconceived notions have been discarded and have given way to providing a design and a machine that is best suited to get the job done. Understanding that the application will not always fit the machine, but, in most cases, the machine should fit or suit the application is a foremost consideration in the engineers' design criteria.

Jan 1, 1973

By Donald C. Rotherham

The Endako, British Columbia, deposit was initially discovered in 1927 by two local men, Charles H. Foote and Alf Lagdon, who were at that time on a hunting expedition. Four mineral claims were located to cover an area of quartz-molybdenite float that was centered on two small ridges. They subsequently uncovered a 0.5-m (1.6-ft) wide vein on which an inclined shaft was sunk to a depth of 8.3 m (27.2 ft) in 1934. Additionally, a short adit was driven to intersect another vein. Numerous trenches and small pits were also dug. Small test shipments of vein material from this early work were sent to G.S. Eldridge and Co. in Vancouver for metallurgical testing. A concentrate assaying 89.2% MoS, was produced with a recovery reported as 93.3%. The concentrate was essentially free of copper, arsenic, and phosphate. The property was examined by many geologists and engineers during 1934 to 1952, but the only work done was undertaken by the owners in order to maintain their claims in good standing. In 1952, Kennco Explorations (Canada) Ltd. carried out a limited program of bulldozer trenching, sampling, and geological mapping before relin- quishing their option. In 1956, American Standard Mines Ltd. acquired an option on the property, but no assessment work was apparently recorded and the property was allowed to lapse. The key claims were restaked in 1959 by C. Riley and H.T. James of Vancouver. The property was optioned from the new owners by Andrew Robertson in July 1961, and a small amount of trenching was conducted. Robertson, on behalf of his own company, R & P Metals Corp., reoptioned the property in January 1962. The initial results of this work were favorable and justified further exploration. The additional finances required to continue the program resulted in the formation of Endako Mines Ltd. (N.P.L.) on June 21, 1962. Field work by R & P Metals and the first Endako Mines exploration was directed by Bob Couts.

Jan 1, 1991

By M. Karmis, C. Haycocks

The evolution of longwall mining is briefly traced from its inception in England in the 1620's. In the beginning this method recovered 90% of coal with roof closure controlled by packs and walls. Mechanization began with kerf cutting, crude face conveyors, and improved face support. Full face mining was accompanied by the introduction of self- advancing hydraulic supports. U. S. longwalls evolved a retreating system to recover blocks of coal outlined by room and pillar panels. Computer control combined with the most modern technology have greatly increased productivity. Past trends are used to predict future technological directions.

Feb 24, 1997

By S. B. Kim, J. Hong, K. Park, W. Kim, H. Kim, Y. Han, J. Choi

"For the first time, the influence of stearyl trimethyl ammonium chloride (STAC) as a collector, on the flotation behavior of lepidolite (Uljin, South Korea) was systematically examined in Denver Sub-A cells. Flotation tests were carried out by varying amount of STAC (50–200 g/ton), feed size (-65, -100, -150, and -200 mesh), and solution pH. The impeller speed of 1000 rpm, flotation time of 10 min and AF-65 (a frother) of 250 mL/ton were invariably applied. In order to complement flotation experiments, zeta potential measurements and XRD analysis were conducted. XRD results showed that the ores were mainly composed of lepidolite, muscovite, quartz, calcite and albite. In addition, zeta potential results showed that isoelectric points were about 2.5, 2.3, and 9.7 for quartz, albite, and calcite, respectively, and lepidolite was determined to be less than 2. Overall, the results of 3-stage flotation showed that Li2O grade and recovery tended to increase with increasing STAC dosage and decreasing feed size. In addition, Li2O grade increased with decreasing pH. The results were explained by the extent of the interaction between STAC and each mineral.INTRODUCTION A great number of potential applications of lithium are being developed currently by the thermonuclear fusion power generation industry(1,2) as well as by the battery and fuel cell industry(3). Even though lithium is mainly consumed in the form of lithium metal and some lithium compounds, about 10% of total lithium production is consumed directly as mineral concentrates by the ceramic industry for the manufacture of special ceramics and mica based glass-ceramics(4). Granitic pegmatites normally contain feldspars, quartz, and mica in addition to lithium-bearing minerals such as spodumene (LiAl(SiO3)2), petalite (LiAlSi4O10), and lepidolite (KLi2Al(Al,Si)3O10(F,OH)2). The amount and grade of metallic minerals tend to gradually decrease and become lower, leading to the increase in the price of base metal or metallic compound(5). Accordingly, recent studies have been extensively devoted to developing the technique to improve the grade of metallic minerals from low grade metallic ores(6,7). Nevertheless, studies regarding the improvement of Li grade from lepidolite ores are very scarce. Lepidolite is a phyllosilicate mineral of the mica group and is often associated with other minerals such as calcite, muscovite, feldspar, and quartz, which need to be separated for lepidolite enrichment(8). Many studies have reported the flotation techniques for separating calcite, muscovite, feldspar, and/or quartz from various targeting minerals(9-11); however, there has been no attempt to investigate physico-chemical properties of lepidolite and its separation from such types of gangue minerals through flotation. Hence, in this study, for the first time, flotation has been carried out for the quaternary ammonium salts (stearyl trimethyl ammonium chloride (STAC, (CH3)3CH3(CH2)16NCl))-lepidolite system based on only the electrokinetic property of minerals that consist of lepidolite ores without adding any depressant to get an initial insight on its flotation behavior. The experimental variables that influence the lepidolite flotation such as amount of collectors, feed size and solution pH have been also examined."

Jan 1, 2015

By K. Y. Haramy

A scale-invariant theory of the strength and deformability of rock masses in static equilibrium and at incipient failure is proposed. The theory provides a rationale for designing structures in rock. This paper presents results of experiments conducted by the U.S. Bureau of Mines and theoretical methods to determine and interpret in situ strength of rock masses using the borehole shear tester.

Jan 1, 1995