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By Robert E. Mead

During the past three years the New York Trap Rock Corporation has been restricting blasting operations to days when favorable atmospheric conditions prevailed. By favorable atmospheric conditions is meant the absence of temperature inversions or isothermals in the lower atmosphere or under 6,000 feet altitude. Strong wind and wind shear can also cause conditions unfavorable for blasting. As a result of this practice, there has been a marked decrease in the number of blasting complaints received. The New York Trap Rock Corporation operates four stone quarries on or near the Hudson River within 60 miles of New York City. The Company supplies approximately 7,080,000 tons of high grade, crushed and graded aggregate, rip rap and by-products to the New Pork City area annually, This stone is carried to the market by a fleet of company owned deck &cows which are moved by tugs of a subsidiary towing company. Stone from two of the quarries is diabase: and, from the remaining two, dolomite.

Jan 1, 1962

By Yuexin Han, Yanjun Li, Peng Gao, Yongsheng Sun, Qiang Zhang

The non-isothermal magnetization roasting process and isothermal magnetization roasting process of siderite ore were investigated using thermogravimetric (TG) analysis and a real-time infrared gas analyzer. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to analyze the characteristics of samples. The results showed that the decomposition degree and decomposition rate of siderite ore were vitally affected by heating rate and roasting temperature. It was determined that A1 reaction model (f(α) = 1 − α) and A3/2 reaction model (f(α) = (3/2)(1 − α)[−ln(1 − α)]1/2) were the most probable mechanism function of the non-isothermal decomposition process and isothermal decomposition process, respectively. The phase transformation and decomposition mechanism during the roasting process were evaluated. Siderite decomposed in the process of magnetization roasting, released CO and CO2, and transformed into strongly magnetic magnetite. The SEM images highlighted that as the decomposition progressed, the structure of roasted samples was destroyed, and an increasing number of cracks and pores emerged on the surface, which is advantageous to the following grinding process.

Mar 26, 2021

By T. M. Gurr

The United States is the world's leading producer of phosphate rock. In 1975 according to the U. S. Bureau of Mines' statistics, 44.3 million tonnes (48.8 million short tons) of phosphate rock were produced in the United States', which is 40.6 percent of the world's production2. The major phosphate producing areas of the United States are located in Figure 1 and the production for 1975 is listed as follows: Million Million Short Tonnes Tons Florida and North Carolina 36.9 40.7 Western States 5.3 5.8 Tennessee 2.1 2.3 All of these areas produce phosphate from deposits which are sedimentary marine in origin. Occurrences of phosphate exist throughout the United States in numerous locations that are of both igneous and sedimentary origins. However, these other phosphate occurrences vary greatly in extent and economic significance. Georgia, South Carolina, California, Texas, Arkansas, Kansas, Iowa, Alabama, Kentucky and Virginia are but a few of the states in which phosphate is thought or known to

Jan 1, 1977

By Richard L. Breithaupt

INTRODUCTION A shuttle car is a self-propelled rubber-tired haul¬age vehicle designed specifically for underground min¬ing, primarily in coal mines (see Figs. 1 and 2). The drive mechanism is located on the sides of the vehicle, and the load is carried in the center. A chain-and-flight conveyor distributes the load when the car is being loaded by a loading machine or continuous miner and also discharges the load onto a conveyor belt or into a mine car. As the name implies, the shuttle car shuttles back and forth between the working face and the un¬loading point and is not required to turn around. Shuttle cars have served as primary haulage in this country since 1940 and still perform this function in most coal mines today. TYPES OF SHUTTLE CARS Shuttle cars may be battery-powered, diesel-powered, or cable-reel electric powered. Battery-powered cars were used between 1940 and 1950, but are almost out of existence today because of their limited power. Diesel cars have been used in coal mines, but are used mostly in noncoal mines where rules and regulations are not as stringent. Also, objections by organized labor have limited the use of diesel-powered shuttle cars in coal mines. Today, the largest number of shuttle cars are cable-reel cars. Electric power is fed through a cable stored on a cable reel that may have a capacity from 152 to 244 m (500 to 800 ft), depending upon the size of the cable and the cable reel (see Table 1). This, of course, limits the travel of a shuttle car. However, time studies have shown that for the most efficient haulage cycle, the length of haulage should not exceed 91 m (300 ft). As haulage distance increases, the waiting time for the loader or miner becomes longer, and haul¬age efficiency suffers. Cable-reel cars are manufactured in standard hand and opposite standard hand models. A standard car has the operator's control on the left front side and the opposite standard car has the opera¬tor's controls on the right front. Generally a loader or miner operates with two shuttle cars, one of each type. This allows the trailing cable to lie on either side of the entry and prevents the cables from fouling each other. Shuttle cars are designed to operate with either dc or ac power. Cars using dc power are designed for 250-v supply and ac cars are designed for either 440, 550, or 950 v, three-phase voltage. Most coal mines that are relatively level can use dc cars where dynamic brak¬ing is not required. For mines having steep grades (in excess of 15%) ac cars are used because ac traction motors have inherent dynamic braking and are safer when tramming downgrade. A recent innovation in shuttle car design in the last five years has been the introduction of an ac/dc car. This design utilizes ac input power through the cable, and the power is rectified on the car to 250-v do for traction motors. The pump motor and conveyor motor are powered by ac voltage. The main advantage of this design is efficiency-a much smaller cable may be used and the smooth operating characteristics of the dc traction motor is obtained. This prevents shock loading on the traction drive train, which is an undesirable feature of ac traction motors. SHUTTLE CAR FEATURES Elevating Discharge Today, all shuttle cars are equipped with an elevating front conveyor that allows the shuttle car to discharge into a mine car or belt feeder without the use of ramps. Hydraulic Power System Today, all shuttle cars are equipped with an hy¬draulic power system. An hydraulic pump is driven by an electric motor which provides hydraulic power for steering, elevating the front conveyor, and powering the

Jan 1, 1982

By K. J. Sollman

With an ongoing concern for safety and health in the workplace, NYCO® requested three medical evaluations be undertaken to study possible health hazards of wollastonite. Two of the evaluations were conducted by the National Institute of Occupational Safety and Health (NIOSH). One was in 1976 (Ref. 1), and the second in 1982 (Ref. 2). The aim of the two studies was to answer the following two questions: 1. Do wollastonite workers exhibit more respiratory abnormalities than workers not exposed to wollastonite? 2. Is there a relationship between prevalence of respiratory abnormalities and accumulated expo-sure time to wollastonite?

Jan 1, 1988

Refractory gold concentrates often contain sub-microscopic gold that is encapsulated within the crystal matrix of iron sulphide minerals such as pyrite, pyrrhotite and arsenopyrite. To recover the gold, the host mineral must generally be broken down chemically, by oxidative processes such as roasting, pressure oxidation or bacterial leaching, which expose the gold for subsequent recovery by leaching in cyanide solution. The focus of attention in these pre-treatment processes is usually the oxidation of the sulphides to elemental sulphur, sulphur dioxide gas or sulphate ions. Less attention is paid to the deportment of iron and the changes in its oxidation state, although this can have a profound effect on gold and silver liberation, as well as down stream operating costs. Iron sulphide minerals break down completely during pressure oxidation, and dissolve in the sulphuric acid solution that is generated from oxidation of the sulphides. This liberates the tiny gold particles that were originally trapped in the sulphide crystals, and gold recovery during subsequent cyanidation is usually very high (>95%). Iron goes into solution in the oxidation process, initially as ferrous sulphate, but this is rapidly oxidized to ferric sulphate, which then hydrolyzes and re-precipitates. The form of the precipitate varies depending on the operating conditions in the autoclave and the presence of certain metal cations. When the acidity in the autoclave is quite low (<20 g/L H2SO4) and the temperature is high (>200OC) the formation of hematite is favoured. When the acidity is high (>20 g/L H2SO4) and the temperature is relatively low (160 to 200OC), the formation of basic iron sulphate is favoured. If the ore or the leach solution contain significant levels of certain cations (such as Na+, K+, NH4+, Ag+ or Pb2+) and the acidity is high (>20 g/L H2SO4), jarosite compounds are favoured. Hematite is the desired iron product in the autoclave discharge, for both metallurgical and environmental reasons, but it is difficult to operate an autoclave under the conditions required for effective liberation of gold without converting some of the iron to basic iron sulphate and/or jarosite. These compounds fall into a category of iron compounds known generically as iron hydroxy sulphates, all of which can cause significant processing and environmental problems in the downstream gold process. This paper deals specifically with basic iron sulphate; the conditions under which it is formed in an autoclave, the problems that are caused by its presence in the feed to a cyanidation plant, and possible remedial strategies that can be adopted, both in the autoclave and downstream.

Jan 1, 2010

By Patrick G. Hatcher

Studies of sedimentary humic acids by nuclear magnetic resonance (NMR), stable isotopes, and elemental analysis show they are derived by oxidative degradation of complex plant macromolecules that are insoluble in aqueous or organic solvents. The mechanism by which humic acids originate is fundamental to our understanding of the role of organic matter in ore deposition, because these substances can complex and mobilize a number of metal ions. The organic matter associated with uranium ores of the San Juan Basin, New Mexico and Carlin-type disseminated gold deposits of Nevada has certain organic geochemical characteristics that suggest an origin from humic acids.

Jan 1, 2013

By S. B. Patton, T. Novak

To fully utilize a ventilation simulator as a planning and production tool, the network database must keep pace with mining progress. By using AutoCAD&apos;s™ attribute-definition function, the branch data and node coordinates can be stored as part of the branch-diagram file and updated with the drawing. Attributes are drawing entities that contain text which can he extracted in a standard spreadsheet format or as an ASCII text file. The data can be subsequently loaded into a ventilation simulator. This paper presents the methodology for using AutoCAD&apos;s™ attribute feature in a ventilation simulation format.

Jan 1, 1995

By Basar Arioglu, Mustafa Tanriverdi, Seok Jae Seo

"INTRODUCTION Istanbul is a unique megalopolis connecting two continents. Population growth and economic development require permanent solutions and continuous investments on the transportation infrastructure. While the average population growth rate in Turkey is around 1.3% per annum, Istanbul is growing at an even faster rate of more than 1.5%. Even more striking is the fact that car ownership in Istanbul is increasing 5% a year, which is four times faster than the population growth. Although Istanbul Metropolitan Municipality (IMM) has worked persistently to improve the quantity and quality of the public transportation system in the city through, in particular, extending the available rail system network, the need for extra roads has always fallen behind demand. To make things worse, Istanbul is divided by the Bosphorus Strait, the large waterway connecting the Black Sea to the north and Marmara Sea to the south, which leads to the Mediterranean. This waterway is crossed via two suspension bridges, the Bosphorus Bridge built in 1973 and the Fatih Sultan Mehmet Bridge built in 1988. Current daily traffic across the bridges is around 450,000 vehicles per day. Ever increasing cross-Bosphorus traffic demands require other routes to be in place a soon as possible. While a third bridge farther north is currently under construction, yet another tunnel crossing is coming to the end of construction and is planned to be in service by December 2016. Being implemented under a Build-Operate-Transfer (BOT) model, Istanbul Strait Road Tunnel Project (ISRTP, the Project) has been under the spotlight not only because of its distinctive technical characteristics but also because of its robust business model, exacting financial and legal arrangements, diverse stakeholders and challenging organizational management structure. The following paragraphs offer an overall view of the Project from inception to where it stands now and extend to the imminent operational phase, touching lightly on all major aspects of this challenging journey."

Jan 1, 2016

By Constance F. Acton

This paper presents an overview of -- the carbon-in-pulp process for gold and silver recovery as seen in the early 1980&apos;s. Traced back to its origins in the mid-nineteenth century the process development through the present state-of-the art is described. The process technology and equipment design are described in detail for the carbon-in-pulp process. A typical process flowsheet is given with a description of appropriate design criteria. Technical advantages and disadvantages as compared to the traditional countercurrent decantation process are discussed including some illustrative comparisons of capital and operating costs. A summary of currently operating carbon-in- pulp plants throughout the world is given with an insight into future developments in this industry.

Jan 1, 1982

By W. S. Sadik

This paper presents the ventilation design for an underground testing facility in a salt medium. The underground workings consist of two-12 ft. (3.66 m) diameter watertight shafts and approximately 6000 ft. (1830 m) plus of drifting. These facilities are designed for the purpose of providing access for an in-situ testing of a salt horizon in which a variety of hazardous and non-hazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1988

By K. C. Shaver

The Sloan Ranch kimberlite complex is located approximately 130 km north-northwest of Denver in the Precambrian core of the northern Colorado Front Range (Figure 1). A Devonian age for the complex is suggested by the fossil assemblages in limestone xenoliths (Chronic and others, 1969), and by paleomagnetism of the kimberlite (E. E. Larson, personal communication, 1986). The presence of diamond was first reported in rocks from the Sloan diatreme by McCallum and Mabarak (1976). Prior to this time, the distinctive- appearing host rock of the Sloan diamonds had been quarried for use as terrazzo stone; examples may be seen in the floors of the airports in Cheyenne and Laramie, Wyoming. The Minerals Division of The Superior Oil Company obtained a lease on the Sloan property in 1980. During the next four years Superior built and fine-tuned a highly efficient diamond recovery facility, explored and tested the Sloan deposit, and used Sloan as a site for testing numerous exploration techniques for future use in a continuing exploration program in the Colorado-Wyoming kimberlite province. The Sloan property was ultimately determined to be sub- economic, but the lessons learned there have been very helpful in subsequent exploration efforts.

Jan 1, 1987

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented in this paper.

Jan 1, 1969

By Klein E., Kinscher J., Lizeur A., De Santis F., Lhoumaud E.

Seismic repeaters are rarely observed phenomena in underground mines. However, recent studies in Garpenberg mine (Sweden) have demonstrated that seismic repeaters and multiplets may represent significant portion of the total number of microseismic events (> 80 %) related to excavation operations. Detailed seismic analysis, involving template matching, multiplet clustering, double-difference relocation, source parameter and mechanism estimation, and interevent time analysis, suggest that seismic repeaters represent brittle frictional parts (asperity) of creeping, planar shaped, pre-exiting structures of several meters length. It is furthermore suggested that seismic repeater occur preferentially in weak rock-mass materials (e.g. talc) associated with strengthening friction behaviors. These results may imply that postblast related stress redistribution may be governed by “silent” aseismic movements in preferentially weak rock mass materials, what questions the reliability and performance of seismic monitoring to survey stress evolution during excavation operations. However, once the seismic and aseismic coupling processes and the geological nature linked to repeater occurrences are better understood, their detailed monitoring bears also opportunities to survey and quantify aseismic post-blast stress transfer. Here we present ongoing investigations on repeater occurrences aiming at better understating on their geological and geomechanical origin. Furthermore, we try to develop advanced monitoring tools helping to quantify aseismic slip and to provide criteria for seismic hazard as asperity density and the related potential to generate larger dynamic rupture zones. For this respect a local monitoring network has been set up close to certain repeater target families. Furthermore, geological well log drilling throughout repeater occurrences as well as geotechnical strain measurements (e.g. extensometer, optical fiber etc.) are currently conducted to provide crucial information on the geological nature of repeater and to quantify and characterize background creep induced from excavation.

Apr 26, 2022

By III Cocanour

The line scan video photometer is a personal computer (PC) based, software-driven instrument which is used for the real time, on-line analysis of industrial process streams. The novelty of the instrument lies in the integration of its various components: (l) a true Red/Green/Blue (R/G/B) color video camera; (2) a unique, line-scan color sample and hold technique which provides a 4 to 20 mA analog signal to a commercial 12 bit analog to digital (A/D) converter; (3) software which converts data through a color absorbance algorithm to correlate elemental color to concentration; and (4) software-based control which utilizes color data, along with temperature and conductivity data to control process equipment. The photometer can be used for noninvasive analysis wherever color hues are representative of process variables such as chemical concentrations or mineralogy color reflectance. The line scan video photometer has been successfully demonstrated in solvent extraction/electrowinning (SX/EW) and ball mill circuits of copper producers.

Jan 1, 1996

By A. D. Davis

The disposal of spent ore from cyanide heap-leach processing facilities is of concern to the mining industry, regulatory agencies, and the public. Disposal of several hundred million tons of additional spent ore is planned in the western United States during the next decade, with increased amounts likely if gold prices rise. In the past decade, more than fifteen million tons of spent ore have been disposed of in the Black Hills. South Dakota&apos;s off-loading criterion for cyanide has been set by the state&apos;s Department of Environment and Natural Resources at 0.5 parts per million (ppm) as weak acid dissociable (WAD) cyanide. Nitrate off-loading limits vary for each mine in the state, depending on ore type and other factors. Nitrate concentrations in leachate from spent ore depositories could be caused by conversion from other nitrogen-containing species. One likely source of nitrate is residual explosives from blasting of ore. Previous work on the combustion products of nitrogen explosives has shown incomplete 3xidation (Johansson and Persson, 1970). Another likely nitrate source is degradation of cyanide to ammonia, followed by oxidation to nitrite and nitrate.

Jan 1, 1994

By G. A. Parkison

The sequential copper analysis method is a particularly useful technique to semi-quantitatively define the geologic, mineralogic, and metallurgical types and zonations commonly associated with porphyry-type copper deposits. The method is based on the partial dissolution behavior displayed by the prevalent copper minerals malachite, chrysocolla, chalcocite, and chalcopyrite to solutions containing sulfuric acid and sodium cyanide. Results from sequential analyses of the sample and analytical residue using sulfuric acid followed by sodium cyanide and then aqua regia solutions when compared with conventional total copper analyses can determine the amounts of leachable oxide minerals, leachable secondary sulfide minerals, and primary copper minerals, respectively. Sequential assay analytical results and interpretation are presented for copper deposits in Chile, Mexico, and the United States.

Jan 1, 1995

By Donald P. Schlick

Gentlemen, today I would like to talk to you about metal and nonmetal mine health and safety--past, present and future. Briefly, I will comment on the past because it is important to an understanding of our present activity and our plans for the future. Federal inspection of noncoal mines was not authorized until 1966, when congress passed the federal metal and nonmetal mine health and safety act; public law 89-577, with the passage of this act, the federal inspector, for the first time, had the delegated authority and responsibility to enforce health and safety regulations designed to prevent personal injuries and occupational diseases, the new law also provided for the education and training of our miners; assistance to the operator through the transmission of technical and scientific information and assistance and equally important, the law made provision for state participation in the congressional mandate to prevent injuries and save lives in the mineral industry, Before I tell you about our program and our future plans, I want you to know that I am here to listen as well as to talk! In my view, the only kind of communication that is meaningful is two-way communication. Our nationwide progress in metal and nonmetal mine health and safety during 1972 cannot be measured in reduced fatalities or injuries. The unforeseen tragedy that took pace in Kellogg, Idaho, in may of last year mode that almost a certainty.

Jan 1, 1973

By G. Kraemer, J. A. Le Gac, P. R. ZETTWOOG

I. INTRODUCTION During the course of our activities in assisting mining companies, we have had access to the monitoring results for personnel from a large number of uranium mines. The results differ greatly from one mine to another. One of our objectives has been to discover the origin of these differences. It is evident that they are largely due to variations in the geological context, to mining methods, and to the organization of the work ; but we also found that the rigor with which measures are implemented to prevent the personnel from being exposed to radiations is also a cause. In order to advise mining operators effectively, we have asked ourselves the following question Given the dosimetric results of a mining site, how can it be known - if occupational exposure has been reduced to the lowest possible level (dose optimization principle recommended by the ICRP) ; - if the exposures were justified, which would not necessarily be the case following a questionable choice of the mining method, for instance, or a lack of efficiency in the maintenance and repairs of ventilation apparatus or even an excess of radiation protection. It is necessary to establish some criteria, while taking into consideration the specific conditions for each mine, in order to determine whether a mining company is adequately implementing radiation protection procedures. This need led us to attempt a modelization of the occupational exposures of uranium miners ; the preliminary phase is presented here. Although voluntarily still very basic, this model makes it possible to demonstrate the role of certain dynamic or passive variables. Moreover, the model presents the concept of specific irradiation of a mining site equal to the collective dose received per ton of uranium metal supplied to the uranium mill. The specific irradiation can therefore be used to indicate the effectiveness of radiation protection procedures at a given mining site. This model can be used for - previsional exposure studies based on the use of data gathered at each site, making it possible to compare various work methods and to determine prevention means ; - qualification of "radiation protection" procedures at a mining site ; - detection of unjustified exposures ; - research of ways to reduce inevitable exposures. 2. DETRIMENT TO BE ASSOCIATED WITH A GIVEN EXPOSURE DISTRIBUTION Respecting exposure limits ensures that delayed stochastic effects are the only health risks to workers. If the hypothesis of linearity in the dose-effect relationship is applied, the detriment to a group of workers is proportional to the sum of exposure for all the workers, or the collective exposure usually expressed as man x rem. On this point the linearity of effects hypothesis makes it possible to consider that two different standard deviation distributions having the same mean value are equivalent. It would be possible, then, to reduce the standard deviation by changing the distribution of workers at the various working places without changing the mean exposure value. In other words, without taking into consideration the practical implications, individual limits can be respected by rotating the personnel or by reducing the individual working period which would be compensated by increasing the number of workers. The collective dose would remain the same, which would justify the use of the concept of collective exposure. 3. "RADIATION PROTECTION" QUALITY INDEX AT VARIOUS MINING SITES Each mining site is responsible for its own collective dose, but it is also responsible for producing a certain amount of uranium metal in the ore sent to the uranium mill. These two quantities must be brought together in order to establish the "radiation protection" quality index of a mining site. This quality index, called-specific irradiation (Ir) is expressed in rem.ton -1 for external irradiation, in mJoule.ton-1 for inhaled [a]-energy, and in Ci.ton -1 for inhaled radon *. The specific irradiation represents the health hazard which must be associated to the extraction of one ton of uranium metal. Figures la and lb present a system of coordinates for which the axis of the abscisses is graduated in tons of U metal and the axis of the ordinates is graduated in units of collective exposures. In the EEC, the regulation is based on the measurement of the amounts of radon 222 inhaled.

Jan 1, 1981

By Chee S. Theng

As the 2017 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2017 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 342. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2017 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH), a special review article on Heap Leach Modeling, and articles from two Special Issues on Rare Earths. The 2017 Transactions consists of a total of 54 technical papers, encompassing all 21 papers published in 2017 in the Technical Papers Section of Mining Engineering (Vol. 69) and all 24 papers published in 2017 in Minerals & Metallurgical Processing (Vol. 34). Additionally, this volume contains 9 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our Publications staff. As the 2017 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2017