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By Tsunenori Shibata, Kazunori Jimbo, Kaoru Toya, Masafumi Matsumoto, Jinya Mitsui, Toshinori Tsuji

"The Toyama Line is under construction as a natural gas pipeline with a length of 102 km from Itoigawa City to Toyama City. A 2 km-long tunnel section of the pipeline that we are reporting here is being excavated in a mountain area away from an urban area. The geology under which the tunnel is constructed is collapsible fractured breccia slate and Holocene sandy soil. Other tunnels of the Hokuriku Expressway and Hokuriku Shinkansen are in service above the tunnel route. From the starting shaft on Toyama side, conventional tunneling was adopted to facilitate excavating the base rock layer and maintain enough distance from the Hokuriku Expressway tunnel. From the starting shaft on the Itoigawa side, TBM tunneling was adopted to cope with the unconsolidated soft ground for a 200 m-long section from the shaft. We will discuss the issues and countermeasures concerning the selection of a tunnel route and excavation methods, performance of both conventional and TBM tunneling, and underground connecting of these tunnels excavated by conventional (NATM) and TBM methods under a high groundwater pressure up to 1.2 MPa. INTRODUCTION AND BACKGROUND The International Petroleum Exploration Teiseki Co., Ltd. (INPEX) is constructing a high-pressure main pipeline network in the Toyama Prefecture area to promote the use and reliable supply of natural gas as shown in Figure 1. As part of the Toyama line project that has a total length of 102 km, A-1 construction, the nearest section to the tunneling starting point in Itoigawa City, where various tunnel excavation methods have been adopted to install the high-pressure pipeline 20 inches in diameter, a 2 km tunnel in the A-1 construction section discussed here is to be excavated by conventional and TBM methods in a mountain area. Based on environmental studies such as traffic jams due to frequent traffic of heavy vehicles disposing of soil, and the effects of dust, noise and vibration during construction, we selected the route to install the gas pipeline in a mountain area as shown in Figure 2, where the impact on the surrounding environment could be minimized."

Jan 1, 2016

By Bruno Bussière, Michael Aubertin, Robert P. Chapuis

Covers with capillary barrier effects (CCBE) have been used in recent years as gas barriers for the isolation of wastes, including reactive mine tailings. Capillary barrier effects help to maintain a high degree of saturation in the moisture retaining layer, which then reduces gas flux. Various factors affect the degree of saturation of the moisture retaining layer in a CCBE, such as the material water retention characteristics and layer thickness. Slope geometry can also influence the hydrogeological behaviour of a CCBE, but this factor has frequently been ignored in the past. In this paper, the authors show some results of a numerical study that illustrates the influence of slope on the behavior of capillary barriers made of different types of material. The numerical model calculations are based on an actual case of a CCBE constructed in northern Quebec. This investigation shows that the water content profile is greatly affected by the position along the slope. Thus, it is necessary to evaluate the influence of the geometry to properly establish the performance of a cover system.

Jan 1, 2000

By Ali Ekrem Aritan

Exposure to hand-arm vibration (HAV) among the labor force in the mining industry can result in permanent vibration diseases such as behavioral disorders, visual impairment, osteoporosis, pain (mostly in the hands, wrists, and shoulders), circulatory system disorders, and malnutrition. In this study, the vibration exposure of excavator operators working regularly in 25 different natural stone quarries was measured. In addition, the relationship between vibration exposure and rock properties was investigated. Gloved and ungloved vibration measurements were performed and revealed that antivibration gloves reduce excavator operators’ vibration exposure by 7.10–25.95%. Samples from each quarry were characterized with rock mechanics tests. The correlations between the hand-arm vibration measurements and the natural stone physical–mechanical properties (uniaxial compressive strength, Shore hardness, Knoop hardness, apparent density and total porosity) were determined to be over 70%. One finding of the study was that the health risk in excavators cannot be reduced sufficiently by the sole use of antivibration gloves. Furthermore, the excavation of any rock with a Knoop hardness above 121 is associated with an 81% risk of HAV. To increase awareness of the danger of vibration exposure for natural stone miners, training programs should be provided, and technical and operational changes should be implemented.

By David Lynn Passmore

The reliability of mine operators reports to the Health and Safety Analysis Center of the U.S. Deparetment of Labor of days lost from work by injured miners is .267.

Jan 1, 1985

By Keith A. Heasley

Historically, the surface subsidence over underground coal mines has been predicted using empirical profile or influence functions which have little or no connection to the actual mechanics of the subsidence. Without a mechanistic basis, establishing the exact site-specific parameters to use in these empirical methods has been problematic. A practical subsidence predictive method based on mechanics has the appealing capability of allowing the determination of site-specific parameters from fundamental properties of the overburden with minimal field calibration work. This paper presents several case studies where a mechanics-based, boundary-element program is used to back-calculate the surface subsidence associated with various panels at several Northern Appalachian coal mines. The program used in this case study is called LAMODEL, and it incorporates a frictionless, laminated overburden into a general purpose displacement-discontinuity code primarily designed for calculating the stresses and displacements in coal mines or other thin scam or vein type deposits. In this paper, the program is used to calculate both the underground convergence and the resulting surface subsidence at five longwall panels and a room-and-pillar section. The fitted subsidence from the model is compared with the field measurements and analyzed. The results from the case studies in this paper demonstrate that the laminated model with calibrated properties can easily provide moderately accurate subsidence predictions and is fairly flexible for fitting measured subsidence. However, additional subsidence predictive case studies arc recommended in order to ultimately evaluate the potential of the laminated overburden model for practical subsidence prediction

Jan 1, 1999

By Q. Xiao, R. Naidu, W. Li, S. Song

Acid mine drainage (AMD) derives from the oxidation of sulfide minerals, primarily pyrite (FeS2), and is the most severe environmental issue facing the minerals industry. The most common short-term approach to AMD treatment is migration control, such as acid neutralization and metal/metalloid and sulfate removal, through the addition of alkaline materials, including lime (Ca (OH)2), limestone (Ca CO3), gangue minerals and industrial wastes. This requires the continuous input of materials and may result in the production of a vast amount of secondary sludge requiring further treatment and disposal. Addition of chemicals is usually more important in metal/metalloid removal than in sulfate removal unless the sulfate is present in very high concentrations. A more promising long-term strategy for AMD prevention is source control through the complete removal of pyritic minerals and encapsulation of potential risk minerals by coating with impermeable surface layers. This is regarded as the most cost-effective approach, although the mechanisms underpinning this and the implementation procedures are yet to be fully elucidated. It is likely that long- and short-term practices can be combined to optimize the remediation of contaminated mining sites. Some factors such as differing geological and mineralogical characteristics and transportation costs must also be considered for the successful implementation of AMD prevention and remediation strategies. This review also considers some implications for AMD remediation, but the promising bioremediation of AMD is not discussed as it has been extensively reviewed.

By J. O. Guthrie

Newmont has delineated a 600,000+ ounce gold reserve in the Cargo Muchacho Mountains. This is a desert range underlain by Proterozoic(?) Tumco Formation (gneiss) intruded by Jurassic granitic plutons, and cut by low angle shears of the late Cretaceous Chocolate Mountain Thrust event. Gold, associated with pyrite, quartz veinlets, and propylitic alteration, is emplaced along low angle shears. The mineralizing system, enriched in tungsten, copper, zinc and arsenic, was active during Eocene time. Gold reserves are found in eleven areas as moderate to high tenor deposits that may be mined by open pit and underground techniques. Eastmaque Gold Mines Ltd. is developing the deposit.

Jan 1, 1987

By E. J. Wade

My subject is gold price forecasting and monitoring as an important aspect of gold marketing. While I 'm specifically addressing gold, it is understandable that many other commodities could be readily substituted. Gold marketing must be studied as three distinct processes, and it is my intention to cover each of these processes in turn. First I?ll cover the process of gold price monitoring and forecasting in some detail. In order to select a method, or combination of methods, to be used to sell gold a determination of the future price profile is essential. The profitability of the sales effort will be determined, to a large extent, by how accurately the future price behavior of the gold market has been forecast.

Jan 1, 1985

By Anna Gustafson, Sohail Manzoor, Håkan Schunnesson

Sublevel caving operation relies on the estimation of ore grade at drawpoints, as the mine management uses grade to decide whether the material at a certain ring should be loaded or abandoned. Grade is estimated in various ways, including visual estimation, density-based calculation, and sampling and assay methods. The grade estimation at the world’s two largest underground iron ore mines owned by LKAB in northern Sweden is based on the density difference between ore and waste. The calculations assume a constant swell factor, a theoretical fill of 100%, and a linear relationship between bucket weight and material grade. This study evaluated these assumptions in detail based on the loading data for 12,237 buckets and concluded that the method has some shortcomings which render the assumptions invalid. Further research is required to deal with these shortcomings to improve estimation of the material grade.

Oct 17, 2022

By Deborah A. Peacock

"Outer space technology and exploration have reached a tipping point, so that mining and mineral processing in outer space is now a certainty and not a dream. Several competing companies worldwide are on the way to building spaceships to land on the Moon and eventually mine the Moon and asteroids for volatiles, rare earth metals and Helium-3.The Google Lunar XPrize offers a $30 million prize1. China has recently landed a spacecraft on the Moon. The European Space Agency, with cooperation from the United States, has landed a spacecraft, Philae, on a comet. And, Mars One is planning a one-way trip to establish a settlement of humans on Mars.How and why are the Moon and asteroids and their resources of interest to private space industry companies? Why are the Moon and asteroids viewed as a potential business venue?Geology of the Moon and asteroids — Why do we want to mine there?Space enterprises are actively working toward establishing and operating lunar and asteroid mining locations for resource extraction, resource processing, conversion to salable products and distribution of the products and services in space and to Earth and beyond2.Forty-five years ago, the Apollo manned missions to the Moon returned rocks and regolith to Earth, which were studied and analyzed. What they found was that the Moon contains valuable minerals and resources. These minerals are largely due to meteor and asteroid impacts, which have, over eons, created this mineral-rich regolith. These impacts have occurred on Earth as well, for billions of years, particularly early on in the history of the solar system. However, on Earth, wind, water and vegetation have erased most of these impacts. On the Moon, in contrast, the only weathering is caused by subsequent impacts and the solar wind."

Jan 1, 2017

By James K. Wright

This chapter will discuss the use of financial models as an evaluation tool for various phases of decision making from exploration strategy to the analysis of a producing mine. The text of this chapter was not received in time for printing.

Jan 1, 1979

By Casters B. Foster

The U.S. Department of Energy has undertaken, in a cost sharing partnership with industry and utilities, an extensive coal-oil mixture (COM) combustion program in a number of promising applications. One of these is the injection of COM through tuyeres into a blast furnace in lieu of oil. From work done previously, it has been established that COM can be burned in existing oil, fired facilities. The issues being addressed by the current DOE program are: 1) determination of best available technology to achieve environmentally acceptable operation, and 2) determination of applications for which COM can be utilized economically.

Jan 1, 1978

By R. Kramer, A. Habibi

A ventilation survey was conducted in an underground longwall trona mine. The mine is relatively shallow and categorized as a gassy mine. The ventilation system includes three intake and six exhaust shafts, and three surface axial fans ventilate the mine in a blowing configuration. Airflow quantity, pressure losses and air psychrometric characteristics were quantified, and the influence of moving cages and skips in the shaft examined. The benefits of utilizing high-accuracy digital pressure transducers and advanced psychrometers were seen when undertaking a “leapfrogging” survey to gather data needed to build a computer ventilation model. Two underground booster fans with VFDs are idle but available at the mine. The ventilation model was used to determine the optimal booster fan locations to decrease operating cost by reducing the load carried by the main fans. A leakage study was conducted to evaluate the effects on the system of additional pressure from a booster fan. The study finally prepares a future ventilation model for the next 15 years of mine operation and investigates the effect of proposed scenarios.

Jan 1, 2014

By T. H. Ueng

Solving ventilation networks of natural air splitting is a classical problem in mine ventilation. A common approach to this problem is to formulate it based on Kirchhoff's voltage and current laws and obtain the solution by an iterative technique known as the Hardy Cross method. In this paper, it is shown that the problem can be formulated and analyzed as an unconstrained optimization (minimization) problem. The computational experience with the method of conjugate gradients is also discussed.

Jan 1, 1984

By H. V. Fairbanks

The following processes were investigated using ultrasonic treatment in mineral recovery: (1) cleaning coal from coal slurry ponds, and (2) extracting precious metals from tailings and other sources. The treatment entails the production of a water slurry of the material containing the mineral which is made to flow over the vibrating surface of the ultrasonic treatment unit. The vibrations transmitted into the slurry break up particle agglomerates and also produce a scrubbing action on the surfaces of the particles. The treated mineral particles were found to have increased settling rates, better compaction, and more rapid water drainage.

Jan 1, 1990

By H. Rush Spedden

A process has been developed and piloted to reject copper, lead, iron, phosphorus, bismuth, antimony, elemental sulfur, and insol from molybdenite concentrate without decomposing the contained molybdenite and rhenium. The impure concentrate is first heated with concentrated sulfuric acid at 260 to 290°C for 1 hour. This bake not only oxidizes the contaminating sulfides, but also activates the concentrate for later rejection of insol by flotation. Two stages of leaching follow the sulfation step. The first is an acidified water leach which extracts the oxidized copper, iron, and phosphorous; the second leach rejects the lead, bismuth, and antimony into a warm concentrated solution of sodium chloride. Final upgrading is achieved by conventional froth flotation. The chemistry of the process as well as results obtained from its implementation in a 5,000 lb/day pilot plant are presented.

Jan 1, 1971

By E. Oraby, S. Garcia, A. Thurgood, D. Bertoldi, G. O’Malley

Mining and Process Solutions (MPS) most advanced process, GlyCatTM is the only process that can be easily adapted to existing cyanidation plants in the market today whose real advantages over cyanidation are when treating copper containing ores, concentrates or tailings. With such complex material, GlyCatTM requires 70-90% less cyanide addition to achieve the same precious metal extraction. However, GlyCatTM is not simply cyanidation with added glycine. It is a completely different process where the solution chemistry and conditions needed to effectively leach the precious metals are quite different. Downstream however, the process is largely unchanged as the recovery of the leached gold and silver uses existing known processes such as conventional activated carbon or zinc cementation (Merrill-Crowe process). Another advantage is lower SCN, OCN, WAD and no free cyanide in the effluent which can substantially reduce cyanide detoxification requirements and decrease the OHS and ESG risk of the operation. This paper outline some of these differences and presents testwork, piloting and process examples to highlight the advantageous of this new process over conventional cyanidation.

Feb 1, 2023

By R. M. Tyson

Sulfides present in the troctolitic and footwall rocks are placed into one of three major zones (hornfels, cloud, and basal) on the basis of their stratigraphic position and mineralogy. Hornfels sulfides, enriched in Fe, represent remobilized sedimentary sulfide. Sulfides from the Cloud Zone are probably magmatic and are enriched in PGE, Cu, Ni, and Ag. The basal sulfides, composing most of the ore, resulted from contamination of the magma by remobilized sedimentary sulfide. The basal sulfides exhibit a differentiation trend in their mineralogy and chemistry. PGE, Cu, and Ag are enriched with increasing differentiation which is attributed to fractionation within an immiscible sulfide liquid.

Jan 1, 1986

By S. Khoshjavan

Separation of refractory rock phosphate (P2O5 = 11.5%) from the Dalir area, Iran, containing quartz, calcite and other impurities, by calcination and flotation processes has been successfully used to upgrade the phosphate values. Petrographic studies of this ore showed that collophanite was the major phosphate mineral and the main gangue minerals were calcite, dolomite and quartz. The results of characterization studies showed that the liberation degree of apatite occurred below the average grain size of 140 µm. Preliminary flotation tests were used to process the phosphate samples. Results of preliminary flotation tests showed that they don?t contain any desirable efficiency (grade or recovery) of P2O5. Calcination was the best process for preconcentration of this ore. In the desliming stage, about 14.4% of total P2O5 was removed. Encouraging concentrate grades were obtained after flotation with anionic and cationic flotation, successively. The reagent schemes that have been used in this study consisted of COCO-amine acetate and fatty acid as silicate and apatite collectors, respectively, as well as fuel oil and anionic poly acryl amid as promoter collectors. The optimum pH values for direct and reverse flotations of phosphate were 11 and 6, respectively. Experiments conducted using d80=140 µm deslimed fractions has yielded an acceptable grade of more than 30% P2O5 with a recovery of more than 62%. Finally, a laboratory flowsheet for the processing of Dalir refractory phosphate ore has been proposed.

Jan 1, 2011

By J. E. Murphy

The Bureau of Mines demonstrated ferric chloride leaching of galena concentrate on a continuous bench-scale basis. Leaching was performed at 95° C and with a contact time of 15 min. The ferric chloride leaching solution was continuously fed to a leaching tank at a constant rate for periods up to 45 h. In each test a constant redox potential was maintained in the slurry exiting the leaching tank by controlling the concentrate feed rate. In the 45-h test, lead extraction exceeded 99.5 pct, and the lead chloride produced was 99.97 pct pure.

Jan 1, 1984