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By Rafael C. Castro, Geoffrey Hughes, Fredrick (Rick) Vincent, Philip H. Albert

Seven pairs of drop and ventilation shafts, between two and nine feet in diameter, will convey combined sewer flow to a 230-foot-deep, 26-foot diameter storage tunnel. This paper will present case histories for each site. Discussion will include functional requirements, program and site access constraints, structural design, geology, the variety of excavation and lining construction methods used, and lessons learned. Noteworthy observations include the importance of assuring competent ground sup-port at the soil-bedrock interface and of achieving tight verticality tolerance using both top-down and raise bore excavation methods.

Jan 1, 2007

By C. A. Young, J. D. Miller

Thermodynamic data has been obtained for oleate chemisorption at fluorite (CaF2) and calcite (CaCO3) surfaces using adsorption isotherms determined previously at room and elevated temperatures by in-situ Fourier transform infrared/internal reflection spectroscopy (FT-IR/IRS). Linear regression analysis was used to statistically derive free energy data as a function of temperature assuming oleate chemisorption followed Langmuir-type adsorption. Enthalpy and entropy changes were subsequently ascertained from the Clausius-Clapeyron equation and fundamental thermodynamic relationships. Essentially, no difference in the free energy of chemisorption at the two mineral surfaces was found; however, the differences in enthalpy and entropy values were significant. By comparison, the results showed that oleate chemisorption at fluorite surfaces was more extensive and more entropically driven due to more water being displaced. Results correlate well with values determined in the literature for other mineral collector systems. These findings help explain the greater hydrophobic character of fluorite than calcite in both the absence and presence of oleate.

Jan 1, 2002

By S. Yap, F. J. Sotillo, L. P. Irwin, F. M. Utsey

Slimes, especially clays, are detrimental to several processes in the Mining Industry. The efficiency of classification, clarification, gravity separation, and flotation decreases significantly in the presence of slimes and clays. This problem is particularly critical in the Phosphate and Sulfide Industries. To reduce the effect of slimes in mineral processing, several desliming techniques and chemical additives are used, such as sodium silicate, sodium carbonate, sulfuric acid, tripolyphosphate, hexameta phosphate, etc. Lately, the Mining Chemical industry has shift to more “Specifically Developed” reagents that offer the most efficient and cost effective performance, mainly using organic polymers. For this purpose, the Mining Chemical Industry needs to understand the crystal chemistry of minerals, the chemistry of the aqueous media, the interactions in solids-aqueous-gas interfaces, the rheology of the system, and the plant operation conditions and parameters. This paper describes the use of surface chemistry fundamentals on the design of an organic polymer capable of modifying the rheology of clayish slurries of a phosphate ore. The change in the rheological characteristics of the clayish phosphate slurries allow fine ore particles to settle faster by reducing the slurry viscosity. Thus, abetter separation of the ore from the slimes is possible using gravitational or centrifugal forces. As examples of the application of this reagent, industrial and pilot plant tests on desliming using tanks and hydrocyclones are presented. These tests showed the reduction of 32%-36% in ore losses for different phosphate ores during desliming operations, and the increase of cyclones desliming efficiency to 80%. Tests were also carried out to improve the rejection of unwanted iron bearing slimes in phosphate feed. These tests demonstrated that it is possible to reduce by 0.25%-1.23% Fe2O3content in the flotation feed product. As a result, significant economical benefits are observed with the use of this new technology without any adverse effect on down stream operations, such as clay settling or phosphate flotation.

Jan 1, 2003

By J. O. Stephens

During the late 1940's and early 1950?s, the Westinghouse Combustion Turbine Division built and demonstrated a residual oil-burning locomotive on six eastern railroads. Plans were made to convert to burning pulverized coal, and a single combustor was operated at a full-pressure condition in the laboratory for about two years. During the mid-1960's to mid-1970's, there was considerable interest in coal-burning MHD and a combustor was developed which would also be applicable to combustion turbines. In the early 19801s, the BCR National Laboratory (BCRNL) became affiliated with the University of Pittsburgh, and a program was begun, supported by the Stare of Pennsylvania, to develop an all-purpose combustor for use with industrial and utility boilers and eventually with combustion turbines. In this paper, we review the work of almost 40 years, indicate our present position, and propose steps to be taken leading to efficient and environmentally acceptable power generation from coal, and specifically to coal-burning locomotives.

Jan 1, 1986

By J. Holmes Armstead, John L. Dobra

This paper examines some lesser known risks in foreign investment by U.S. companies that derive from international judicial activism by U.S. courts and the potential for extending U.S. anti-trust regulations to companies' foreign operations. The discussion of international judicial activism reviews the implications of the U.S. Second Circuit Court's ruling in the Union Carbide/Bhopal case for U.S. companies investing abroad and the discussion of extending U.S. anti-trust regulations focuses on proposals coming out the Clinton administration's Justice Department.

Jan 1, 1996

By Cherie H. Tilley

The possibility of drilling oil wells from underground locations is not a new concept. It bas not been cost effective for the oil industry in the past and therefore disregarded. Today's state of the art in tunneling and shaft sinking greatly improves the potential for this type of oil field development scheme. This report presents a plan for providing a aeries of drilling bases and the design of the drilling location. The design minimizes the amount of excavation needed to develop the oil field and maximizes the use of rapid excavation techniques.

Jan 1, 1983

By F. A. Renninger

The terms environment and environmental control, when used in today's context, generally imply to the average individual, something to do with pollution and pollution control. These latter terms, likewise, impart visions of fouled air and dirty water attributable largely to the industrial segment of American society. We have been conditioned, by various means, over the past ten years to equate environ¬mental control with pollution control. We have been trained to think of industrial environmental control programs as efforts conceived only to comply with one or more of the recently imposed pollution control regulations. Almost automatically we; approach consideration of environmental control with a degree of pessimism that is we assume that pollution prompted the control program. It is the purpose of this discussion to demonstrate that environmental control. at least as it exists and has existed within the crushed stone industry, involves far more than simply control or reduction of air and water pollution. It involves a dedication to the enhancement of each of the several "mini-environments" which together comprise the total world surrounding any given crushed stone operation. Environmental control, exercised properly, is an optimistic, constructive, forward-looking, enhancing type of activity. It is a function which has been, and should continue to be, willingly and expectantly undertaken by informed management personnel. In short, environmental control. is an activity from which both industry and society can and should benefit.

Jan 1, 1972

By R. K. Singhal

A sizable surface mining industry exists in Western Canada. There are the surface coal mines in the provinces of Alberta, British Columbia, and Saskatchewan producing the bulk of Canadian Coal. The two oil sands plants in Fort McMurray, Alberta producing synthetic crude oil are surface mining operations. Much of the metalliferous mining in British Columbia is carried out by open pit methods. This paper discusses the current surface mining methods in both of these industries with particular reference to Alberta. Issues relating to environmental impact assessment, mine reclamation and mine site closure have been dealt with.

Jan 1, 1995

By Fulian He, Jianhang Chen, Dongdong Chen, Shoubao Zhang

"The Wangjialing Coal Mine is the main colliery of the China Coal Huajin Energy Limited Liability Company. The average thickness of the coal seam in District 201 is 6.21 m. Fully mechanized longwall mining was used in this district. The ventilation roadway of panel 20102 was influenced by the retreat mining of the adjacent panel 20104. Therefore, large deformation and severe roof falls occurred in this roadway, seriously influencing the safety production of this coal mine. To support the roadway, cable truss was proposed to strengthen the reinforcement of this ventilation roadway. First, numerical simulation was used to optimize the reinforcement parameters, including the cable installation angle, cable length, and eccentric distance. Based on numerical simulation results, in-situ tests were conducted in the ventilation roadway of panel 20102 with the cable truss technology. In-situ monitoring results showed that the roof-to-floor convergence and the convergence of roadway on two sides were within the safety range. Furthermore, no apparent separations occurred in the roof. These indicate that based on the designed parameters, the cable truss system can effectively maintain the roadway stability under the severe influence of the adjacent longwall mining.INTRODUCTIONCable bolts are flexible tendons composed of multi steel wires, which are wound into a strand (Chen, Hagan, and Saydam, 2018). They were initially introduced in the hard rock mining industry in the 1960s. Later, they found rapid application in coal mines to maintain the stability of excavations (Wang et al., 2015).The standard cable bolt is composed of seven steel wires with a diameter of 15.2 mm. Laboratory and in-situ tests showed that there is a low bonding capacity between the standard cable bolt and the grout (Craig and Holden, 2014; Chen, Hagan, and Saydam, 2018). Then, modified cable bolts are developed based on the standard cable bolts. They are improved by changing the surface geometry of standard cable bolts, such as birdcaged cable bolts (Hutchins et al., 1990) or nutcaged cable bolts (Hyett et al., 1993). Further tests proved that modified cable bolts have better mechanical interlock and friction between the cable bolt and grout, leading to larger load transfer capacity of cable bolts.Although cable bolts have been used for many years, failure of the cable bolting system still occurs. A common failure mode is the damage of surrounding confining medium while the cable bolt is still hanging in the roof, which is caused by the bond failure of the cable/grout interface (Hutchinson and Diederichs, 1996). To prevent the cable bolting system from failing, the cable truss system is more widely used in mining engineering."

Jan 1, 2019

By A. S. Ibrado

The adsorption of silver on activated carbon from cyanide solutions was studied as a function of concentration, ionic strength and pH. In cyanide solutions, silver exists mainly as the linear Ag(CN)2 complex and adsorbs on activated carbon following the Freundlich isotherm. The uptake and rate of adsorption increase with the addition of KC1 and KNO3 but changes only slightly with pH. In contrast, the adsorption of Cu(I), Zn(II), Cd(II), and Hg(II) shows marked changes with pH, closely following the predominance profiles of their neutral and singly-charged cyano complexes. Clearly, multicharged negative complexes are repelled by the negatively-charged carbon surface. This sensitivity of activated carbon to the charge of the adsorbing species indicates that silver adsorbs as an anion, not chemically bound to the co-adsorbing counterions. For the same reason, activated carbon is selective to metals that form neutral and Singly-charged cyano complexes, namely gold and silver.

Jan 1, 1988

By C. Anderson, B. Schug, C. Cristoffanini, S. Nazari

The Haile Gold Mine in South Carolina is increasing the automation level of their processing plant in order to improve operational stability. One step towards this goal is the application of a Digital Twin concept to provide Virtual Instruments. Haile has engaged ANDRITZ to implement Virtual Instruments at their grinding area hydrocyclones and at their tailing thickener underflow pump. These virtual instruments provide density values in a traditionally difficult location for reliable slurry density measurement. The Digital Twin is a first principles IDEAS1 ™ simulation model, connected in real time to the control system. Results have been promising, with the virtual instrument values matching the physical instrument under normal operating conditions, and showing better prediction under upset conditions. Haile plans to use the virtual instruments as optional process control parameters. INTRODUCTION OceanaGold’s Haile Gold Mine is located near Kershaw, South Carolina, about 50 miles southeast of Charlotte, North Carolina. This location was first mined in 1827, and has produced gold through several operating periods since then, including a heap leaching operation from 1985 through 1992. In October, 2015, OceanaGold acquired Romarco Minerals, the previous owner of the Haile Operation. The current operation began in 2017 as an open pit mine with additional underground resources. The nameplate throughput is 6,350 tpd ore, and 2017 production was 118k oz gold, with 140 to 155k oz gold expected in 2018. Proven and Probable reserves exceed 3 Moz. The process, as shown in Figure 1, includes a primary jaw crusher, comminution with a Semi-Autonomous Grinding (SAG) mill and ball mill circuit, flash flotation, rougher flotation, regrinding, pre-aeration, carbon in leach (CIL) leaching, carbon elution and regeneration, cyanide recovery, electrowinning and refining. The Haile Operation’s inaugural gold pour took place January 20, 2017. Mine life is expected through at least the year 2030. Based partially on prior experience of some key OceanaGold personnel with automation services from ANDRITZ on other projects, OceanaGold decided to include ANDRITZ on the Haile project. The scope of these services for Haile included design and supply of the process control application software, an ANDRITZ dynamic process simulator for operator training, and ANDRITZ Advanced Control Expert (ACE) ®2 systems for the SAG mill, ball mill, and rougher flotation areas. Since startup, ANDRITZ has continued to provide services for the site, particularly related to PLC and HMI equipment, programming and support, ACE system expansion, and the implementation of Virtual Instrumentation. The implementation of this new Virtual Instrumentation technology at Haile is consistent with Haile goals: increased automation, a change in the role of the operator from interactor to monitor, and improved stability by removing human error.

Jan 1, 2019

By A. D. Paananen

With the demand for higher grade feed by the American steel industry and the depletion of the direct shipping ores from the Marquette Iron Range and elsewhere, there was a need to develop the low-grade orebodies. The large reserve of fine grained oxidized iron-formation at the Tilden Mine has been the object of research and development efforts to concentrate the iron oxides as far back as 1949. Preceding the present mining-concentration-pelletizing complex, about 6,500,000 long tons of direct shipping siliceous ore were shipped from the Tilden Mine. Following development of the concentrating and pelletizing flowsheets, engineering and construction was initiated to develop the mine and construct concentrating and pelletizing facilities to produce 4,000,000 LTPY of pellets from this low grade crude ore. Operations started in late 1974 with Algoma Steel, J&L Steel Corp., The Cleveland-Cliffs Iron Company, The Steel Company of Canada, Ltd., Wheeling-Pittsburgh Steel Corp., and Sharon Steel Corp. as participants. Cleveland-Cliffs operates and manages the operation. Due to the non-magnetic nature of the ore and the fine grinding required to liberate the iron oxide minerals, this crude ore was not amenable to concentration by conventional methods. The iron oxides of the Tilden orebody have a grain size of less than 25 microns and recovery of the finer, well-liberated iron oxides is essential. Conventional methods of des liming employing cyclones or thickeners were not feasible because of the excessive loss of iron oxides in the finer fractions.

Jan 1, 1978

By Jose A. Delgadillo

The hydrocyclone problem has been a challenging task for the last 30 years. In the 80’s and 90’s Computational Fluid Dynamics solution to this problem began to appear. These were unsuccessful due to over simplification. In the past 3 dimensional solution with ?-e model and Reynolds Stress Model have been published. In this paper RSM and ?-e models are compared with velocity profiles measured in 75 mm and 250 mm diameter hydrocyclones. It is shown that results are not satisfactory with RSM or ?-e and that a model called Large Eddy Simulation is needed to describe velocity profile evolution and size classification.

Jan 1, 2005

By Charles D. Litton

This paper presents a description of the hazards of smoke from fires, the detectability of smoke using smoke sensors, and the operational characteristics of such detectors. It places in perspective the advantage that smoke detectors have over other forms of fire detection and also provides a discussion of smoke as a significant fire hazard.

Jan 1, 1992

By Donald P. Richards, David W. Campo, Michel Coudry

This paper presents a review of the grouting works of Line 2 of the Greater Cairo MetroSystem. The Nile River alluvial deposits underlying this ancient city provided for a challenging and sometimes difficult grouting project. Permeation grouting using state-of-the-art computerized grouting techniques, as well as extensive ground treatment by jet grout, was per-formed for soil consolidation and/or groundwater control. During the project, over 425,000m3 of ground was treated, requiring 1.4 million linear meters of drilling and PVC injection pipe, 54,000 m3 of bentonite cement and 230,000 m3 of chemical and mineral grout. In addition, over 70,000 m3 of ground was treated using the jet grout method. Relative to major international transportation projects, the grouting works for Line 2 of the Cairo Metro represent one of the largest worldwide grouting endeavors to date.

Jan 1, 1997

By Sam Rosenblum

The anomaly ratio is obtained by dividing the analyzed value of an element by the anomaly threshold value of the element. The sum of anomaly ratios for all anomalous elements in a sample may be compared with similar sums for other samples, so that the samples having the greatest anomaly-ratio totals can be recognized easily. In partial or full-suites-of-ore-elements the use of anomaly ratios is more meaningful than analyzed values because the ratios quickly indicate anomalous elements and call attention to samples and localities that should be investigated.

Jan 1, 1980

By S. Liu

A general account of nitrogen-generating systems, including the surface fixed, surface-mobile and underground-mobile types is presented. These systems have recently been adopted in coal mines in China to prevent and extinguish fires. The paper stresses nitrogen -injection technology and relevant systems of monitoring and stopping air leakage.

Jan 1, 1998

By S. Ripke

Between 2002 and 2004, the performance of a six million ton per year iron ore beneficiation plant dropped significantly. In a classic case of “who done it,” was it the mine, the concentrator, an ore change, or something else? While average annual final product grade decreased 8% (indicated by an increase in silicate gangue from 2.76% to 2.99%), the weight recovery also decreased by 8% (from 37.92% to 34.79%). This represents a loss of 832,000 tons of iron ore worth about $16 million for the two year period! The concentrator had been optimized to produce a high grade wet concentrate as feed to the dry side of the plant. But, did optimizing an individual unit operation’s grade give the best overall plant performance? In this paper, the investigation and solution to this mystery will be revealed.

Jan 1, 2007

By Lennart Mukka

The Kiruna Mine in Sweden currently has three ventilation systems. The first two (a new and old system) serve the production areas. The third system is used for the facilities on the former main haulage level 775. That area includes offices and workshops for load haul dumpers (LHD) and drill rigs. The third ventilation system also covers the crushing and haulage on level 1045. At the present time, the total airflow for the mine is 1,600 m3/sec(3.4 million cfm). The current system serves the levels above the 775 level. The new one is for the levels between 775 and 1,085 m (2,540 and 3,560 ft), which are needed for the new ore body. When all of the production is below level 775, the old ventilation system will be closed down.

Jan 1, 2002

By E. W. Sawyer

Attapulgite is a magnesium aluminosilicate clay mineral which exhibits unique, processing-enhanceable physical and chemical properties that are related to its current commercial uses. Properties of commercial interest are gelling, absorption, adsorption, binding, acid neutralization and many others. Major industrial applications are: (1) absorption by heat treated grades utilized in industrial oil and grease absorbents and in agricultural pesticide carriers; (2) gelling of aqueous liquid products by colloidal grades for stabilization and viscosity control in salt water drilling fluids, suspension fertilizers, liquid animal feed supplements, paints and tape joint compounds; (3) adsorption by heat treated varieties for the removal of catalysts, color bodies and other polar compounds from hydrocarbon streams; (4) gelling of organic liquids by colloidal attapulgite/surfactant blends in oil-type paints, fibrated and nonfibrated asphaltic coatings and mastic compositions, and (5) the binding of feeds and molecular sieve sorpents with colloidal type attapulgite products. These applications and other less common uses and potential uses will be discussed along with, the necessary selective mining and plant processing features related to each property and application.

Jan 1, 1986