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By Li. S. D., R. X. Zhang, K. M. Li, Y. D. Zhang, Y. J. Hou, S. G. Li

A computer aided design software system for long range coal surface mine planning has been developed by the authors. The system is composed of two subsystems: a coal deposite sub- system and a long range mine planning system. The geological parameters are estimated and a grid model is formed, then a 3-D block model can be developed for mining design. The long range surface mine planning system is based on oriented graph simulation and combined approaches to seek for the optimal deign alternative. This mining model consists of a number of sub-models to realize mining design functions such as: calculation of mining volume and coal quality by graph scanning; determination of operational stripping ratio by interactive design; varification of annual coal production; delimitation and development of dumping site; optimization of material flow direction and volumes by Linear Programming; surface mine production scheduling by interactive iteration; etc. The software package was developed on PC computer 486. It features classified menu guide, module structure, figure and graph representation on the screen and flexible interactive functions. This system has been applied to an open cut coal mine and predicted functions have been obtained.

Jan 1, 1996

By J. Mastoris

The determination of the surface area that may be impacted by underground mining is an important consideration in subsidence engineering. A number of parameters have been utilized to identify this influence area, most notably the angles of draw and break. This paper discusses the implications of selecting an appropriate "damage angle" for defining a potential damage area due to mining, within which surface structures may be impacted. Furthermore, the influence of both mining and geological factors (i.e., mining width, depth and overburden lithology) on this angle is examined using the Surface Deformation Prediction System (SDPS) software. Finally, recommendations are given for applying these concepts in subsidence control.

Jan 1, 1995

By Ching L. Wu, Bolek Chytrowski, Peter Frobenius, Dale Roberts

During the past few years, the first stage of the Waste Isolation Pilot Plant, (WIPP) which consists of an exploratory shaft, a ventilation shaft, shaft stations, access drifts and test rooms, has been under construction. Construction of the first stage is scheduled to be completed in the summer of 1983. The U.S. Department of Energy (DOE) is constructing the WIPP facility to demonstrate the feasibility of disposing of defense-related nuclear waste in the bedded salt deposits of the Delaware Basin near Carlsbad, N.M. The project promises to be a proving ground for underground nuclear waste storage facility design and construction. The completed underground plant will extend over an area of 647,500 m2 (160 acres), and 1,360,500 metric tons (1,500,000 tons) of salt will be excavated. The first stage of the project, the Site and Preliminary Design Validation (SPDV) Program, provides for full-scale construction of the major components of the underground facility. Shaft construction and underground development are described. Rock bolt installation is performed as required for roof control. Geotechnical instrumentation is installed to monitor the behavior of underground openings. Direct observation of the constructed shafts, shaft stations, and underground openings is expected to confirm the adequacy of the underground design and allow full-scale construction of the first U.S. underground nuclear waste storage facility to proceed.

Jan 1, 1983

By Xinchun Li, Youdi Zhang

AI is one of the computing methods, artificial intelligence performs its calculation by simulating the intelligent behavior of human beings. It is regarded as one of the most important scientific achievements in the 20th century, A1 has been developed rapidly in recent years with the development of the computer technique .The application of AI in the mineral industry has also obtained rapid progress sine AI has been used in early 1980's, such as evaluation of resource, underground mining, surface mining and mine safety etc. It has played an important role for increasing mining efficiency, improving mining management and ensuring the safety of the miner. An integrated A1 system has been developed for coalmines environment management in this paper.

Jan 1, 2002

By Y. J. Wang

This paper describes a procedure for solving the generalized system of n network equations in n unknowns considering the following ventilation variables and parameters: (a) air quantities, (b) pressure losses or gains caused by the control devices (i.e., fans or regulators), (c) resistance factors, (d) natural ventilation pressure, and (e) fan pressures (as a function of air quantities). The air quantities and pressure losses for all branches in the network are grouped into dependent and independent variables. The branches with an independent quantity are contained in a chord set, and the branches with a dependent pressure loss are contained in a chord set. In addition to the problem formulation, the solution procedure, applying the Newton method, is discussed and illustrated with a numerical example.

Jan 1, 1989

By V. K. Gupta

A detailed experimental study of the variations in grinding rate with particle size, particle load, ball diameter, ball load, mill diameter, and mill speed was carried out for a soft cement clinker and a hard cement clinker. The effects of the ball diameter, ball load, and particle load were observed to be material (hardness) independent, and those of the particle size, mill diameter, and mill speed to be material dependent. A sharp change in grinding behavior was observed for both the clinkers at about 150 µm size. Below this critical size: (1) the hardness difference between the two clinkers became insignificant, (2) variation in the grinding rate with particle size became markedly more pronounced, and (3) mill speed had little or no effect on grinding rate. The importance of these results in the context of process optimization and control is discussed.

Jan 1, 1988

By Jiqing Zhang, Jon C. Yingling, Andrzej M. Wala, Richard Ray

The purpose of this paper is to present how Computational Fluid Dynamics (CFD) simulations can be used to study the flow across the main airways of a mine ventilation system. in particular, the flow through the transition zone between the upcast shaft and main fan ductwork was investigated. These studies consider potential design modifications of this transition zone to reduce the energy cost. Although CFD has many advantages, it does not completely eliminate the need for experiments, which are still needed to validate numerical solutions. For this reason, data collected during actual mine tests and CFD simulations are compared in this pa- per. This comparison allows a better understanding of the flow phenomena. Moreover, once the numerical solutions have been validated, CFD can be used with better confidence to predict the effect of changes in ductwork configurations on energy losses. CFD reduces the number and cost of tedious experiments, while enabling a broader scope of design comparisons.

Jan 1, 1997

By Paul Mitchell, Amy Wheaton, James Rybock

Acid rock drainage (ARD) represents one of the most intractable problems faced by the non-ferrous metal and coal mining sectors, and the creation in the recent past of a number of high-level national and international initiatives reflects the growing concerns of industry, government and other stakeholder groups. ARD is certainly considered one of the most serious environmental impacts caused by mining and the industry's greatest environment-related technical challenge. Additionally, the global depletion of non-acid generating oxide ore deposits and the increasing dominance of sulphide ores means that the potential for ARD incidents will continue to increase. Once initiated, the cycle of chemically and biologically mediated and catalysed reactions leading to ARD generation is difficult to stop. While there is evidence to suggest that the degree of contamination of ARD will decrease rapidly within a relatively short timeframe (Wood et al., 1999), experience in historic mining regions of the world indicates that the problem may persist for centuries at certain sites. Current best practice in dealing with ARD puts the emphasis on prediction and prevention, planned from the outset of the operation and integrated with each phase of the mine site life cycle. The elements that constitute best practice are becoming more clearly defined and as this process of clarification continues industry will undoubtedly accelerate the process of best practice implementation, burying at last the image of mining as a despoiler and polluter of landscapes, an image based on past, rather than current, practices. However, it is equally clear that despite the best efforts of industry and regulators, many sites will continue to generate ARD during operation and following closure - in many cases, a legacy of ARD has been derived from operational and strategic decisions made decades ago, before the risks and impacts of the self-sustaining cycle of ARD generation were properly understood. Add to this ARD generation from poorly managed operations and from historic and abandoned sites, and it becomes clear that the treatment of ARD will be required for the foreseeable future to protect water quality, and ecosystem and human health.

Jan 1, 1999

By R. M. Campoy

In this review of the copper, lead, zinc, and molybdenum industries in Mexico, the author describes how the country's position in the world base metals market and the climate for foreign investment in Mexico have been affected by the nationalization of the banking industry in that country and by recent mining legislation and the current national debt crisis.

Jan 1, 1988

By Levent Ozdemir, Gerald Dollinger

An extensive series of linear and rotary cutting tests were run in soft and medium strength rocks at the Earth Mechanics Institute of the Colorado School of Mines to investigate the possibility of very high speed mechanical excavation for tunnel, raise, and shaft boring. The results of these tests demonstrate that cutter penetrations of 38.1 mm (1.5 inch) and cut spacings up to 228.6 mm (9 inch) are possible in such rock without exceeding the bearing capabilities of the cutters. It was also demonstrated in vertical boring tests that continuous excavation rates up to 38.1 m/hr (125 ft/hr) can be achieved with state-of-the-art technology provided sufficient thrust and torque is available. A predictor model for soft rocks was also developed using the test data. Analysis of this model shows that the errors between the predicted and observed cutter normal loads appear to be independent of cutter diameter, tip width, cut spacing, and depth of penetration. This suggests that the structure of the model is correct with respect to these variables. An analysis of the coefficients in the model was also made and a correlation found between the principal coefficient and Unconfined Compressive Strength. The second coefficient in the model was found to be similar in magnitude to rock properties such as Brazilian Tensile Strength, Shear Strength and Point Load Index.

Jan 1, 1989

By Dennis Ofiara, Paul Zick

Two 8.2 m diameter flood control tunnels are being constructed in the Taylor Shale Formation beneath San Antonio, Texas. These tunnels use precast concrete segments as final lining. This paper describes the features of the segments chosen for this project. The tunnels are being excavated with a hybrid Tunnel Boring Machine. This paper also describes the features of the TBM which make the machine compatible to the type of segments chosen.

Jan 1, 1989

By L. Max Scott

[INTRODUCTION] The significance of gamma exposure to uranium miners has been recognized only in the last few years. Most ore deposits which have been underground mined, were 1% or less U308. Full-time mining of this grade ore can result in exposure exceeding 1 Rem per year. Several companies in Saskatchewan are planning to mine recently discovered ore bodies which contain ore pods in excess of 10% U308. The purpose of this paper is to present dose data which can be used to estimate gamma exposure from high-grade ore deposits, and to present mining techniques which will minimize miner exposure. [Dose Estimates] When one has a point source of radiation, the conventional laws of isotropic emission and the fall of dose with square of the distance, make dose calculations relatively easy. However, if one has an area source of infinite thickness, the assumption must be made that a uniform gamma flux is being emitted from all faces of the source (Figure 1). Dose from gamma emission would fall off only due to air attenuation up to such a distance at which the source can be considered to be a point source (usually 10 times the largest dimension of the source). For short distances, such as to the cab of ore-moving equipment, the dose reduction would be negligible. Assumptions: 1) Radium and gamma-emitting daughters are in secular equilibrium with uranium. 2) All gamma radiation is emitted from radium and its daughters. 3) Average gamma energy of 0.8 MeV. 4) Uranium ore has a linear attenuation coefficient of 0.212 cm-1, similar to that of Si02(sand). 5) Uranium ore density of 3.0 gm/cm3. 6) One curie of radium emits 6.84 x 1010 photon/sec(l). 7) One percent uranium ore contains 1 x 10-8 Ci/cm3 of radium. 8) Each MeV of 0.8 MeV photon results in a dose of 2.10[ ]10-3 mRem/hr. per MeV/cm2 -sec. 1) 9) Minimum ore depth 100 cm. 10) Linear attenuation coefficient instant for radium gamma of 0.374 cm -1 [ ] The photon flux from a radioactive slab is computed as follows: [Flux = photon/cm3 3(1) 2u S] [where, us is the linear absorption coefficient of s the source (uranium ore).] Thus, 1% uranium ore, in the form of an infinite slab, emits 1613 photon/cm2-sec, which results in a dose rate of 2.71 mRem/hr. Since the dose from an infinite slab is the same as a dose from an infinite radius right circular cylinder, the only correction needed from the above dose rate is for finite radius and point of dose above the end of the cylinder (Figure 2) [Dose = mRem/hr. {E2(bl) - E2(b3) - [(E2(b1sec[E] -E2(b3sec[E]]cos[O](1)]

Jan 1, 1981

By Lisa Shevenell

Three pits at the Getchell Mine contained water during a hiatus in mining activity (1968-1983). For this period, expected concentrations of As, C1, SO4 and TDS resulting solely 16om evaporative concentration were computed. Computed values are 1.6 to 2.3 times greater than those measured in local groundwaters. However, computed values fix As, SO4 and TDS are lower than measured values in the pit lakes. In some cases, the computed values are only 8% of the measured pit lake values, indicating a major control on water quality via water-rock interactions. In contrast, computed C1 values exceed measured pit lake concentrations.

Jan 1, 2000

By S. K. Kawatra

Various types of mathematical descriptions of the flotation process are used in the design of a full scale flotation circuit. Mechanistic descriptions developed under controlled laboratory conditions establish theoretical residence time requirements. Empirical models, describing flotation performance as a function of full scale operating variables, are established from one flotation system and applied to another hypothetical system. Problems of design by mechanistic modeling, such as scale up factors, can be alleviated if the model is developed from a full scale flotation circuit. However, the numerous uncontrollable variables encountered in a full scale operation would preclude the practical application of such a model. Incorporating empirical relations into the full scale mechanistic model will facilitate its effective use as a guide for flotation circuit design. A semi-empirical model has been developed that promises to offer a more effective means of flotation circuit design.

Jan 1, 1982

By Yao Zhou

Under the United Nations Convention on the Law of the Sea (UNCLOS), the international seabed area (Area) and its resources are the common heritage of humanity (CHH). Patent rights can be incompatible with the CHH doctrine and its underlying principles because patent holders might charge unjustifiably high prices to license patented technology for exploring and exploiting the Area’s resources (creating a "patent holdup" situation), might choose not to license, or might license exclusively when doing so would contravene CHH principles. However, a reasonable patent licensing regime can contribute to sharing the benefits derived from the Area and promote environmental sustainability. Provisions of the UNCLOS that stipulated compulsory technology and financial transfers were removed in the 1994 Agreement relating to the Implementation of Part XI of the UNCLOS (1994 Agreement), but to promote equity and sustainability I propose a voluntary licensing regime modeled on the concept of reasonable and non-discriminatory patent licensing (RAND) that has been used in other contexts. The International Seabed Authority (ISA) or another entity will need to coordinate and promote this licensing regime through governance of intellectual property (IP) derived from the Area. This proposed approach can better effectuate the CHH doctrine and its underlying principles.

Sep 1, 2014

By Fang-tu Wei

The purpose of developing this system is to monitor the operating status of the fully mechanized mining system in order to raise it's reliability. The completely mechanized coal mining system is a complex dynamic system, involving many sub-systems. It is the key of the mining process as well as a connected system composed of each working procedure. Any hitch in breaking, loading or transporting will interrupt the mining process. The analyses of the operating data has proved that the reasons causing the interruption of the extracting processes mainly come from the inner of coal face. Hence, after the installation of the MINOS system in England, the delays of belt conveyor sub-system were reduced. But the production increment was not as much as expected.

Jan 1, 1986

By Joseph Lynch, John DiPonio

This report refers to the Chicago Deep Tunnel Contract 13A, which was the first contract let in the City of Chicago requiring the construction of deep drop shafts for the transportation of high level sewage to the deep tunnel system. The basic contract required the contractor to construct certain drop shafts designed to deliver surface and high level sewage to the deep tunnel system approximately two hundred feet below. The design of the drop shafts was in a degree affected by their proximity to the existing deep tunnel. The tunnel, approximately three and one-half miles long, was to have five shafts dropping sewage at five locations. Four of the drops were approximately one-half mile apart and spaced from the dead end of the tunnel. One shaft divided the remaining two miles from the existing work shaft at the southeast end of the tunnel wherein a 220' deep pumping station was to be built. The existing tunnel had been built some time previously and all dewatering had stopped, allowing the tunnel and main shaft to fill with water. According to the plans, the drop shafts were all between fifty and ninety feet north or south of tunnel center line, and located in heavily built-up residential and industrial property. This then defines the problems: How do we control the water. If we excavate from the top down, how do we handle the slurry and the muck from five locations. How shall we construct the connecting tunnel between

Jan 1, 1997

By R. Houot, C. Leschevin, G. Gillet

In mineral processing, conventional magnetic separators are equipped with traditional magnetic circuits (magnetic iron yoke with copper coils or iron-clad solenoid) that develop magnetic fields of less than 2 T'. For minerals of low magnetic susceptibility, use of these circuits has many disadvantages. Only a separator with a superconducting magnet can contribute to solving the problems and produce a high magnetic field. This paper presents and describes a magnetic separator having a superconducting magnet with integrated closed circuit for helium liquefaction. The system generator and maintenance are simplified by extensive automation realized by a versatile program- mable autocontrol unit. A comparative study if the results on concentration and purification of different raw materials with the new and with conventional separators is described.

Jan 1, 1987

By Greg Bold, Mahmood Khwaja, Yuannian (Jerry) Wan, Michael S. Schultz, William Simcoe

Beaver Creek Clean River Project will satisfy the consent decree requirements by capturing and treating combined sewage overflows. The project consists of, approximately, 2,700 feet of 30-inch trenchless pipe installation, a new screening/disinfecting facility, an expansion of an existing diversion structure, and a 72-inch internal diameter, 530-foot long mined tunnel. The tunnel portions are being progressed as early release packages. This paper presents the geotechnical exploration program and the subsurface conditions encountered; interpretation of the geotechnical conditions; and, approach to developing stand-alone packages for the tunnels to mitigate construction and schedule risks and continue to advance the project.

Jun 13, 2021

By B. J. Swenty, J. L. Hubbard, R. L. Peyton

Based on the results of the National Program of Inspection of Nonfederal Dams conducted by the US Army Corps of Engineers during 1977-1981, Missouri was found to have the highest number of "unsafe" dams in the nation. Many of the dams classified as unsafe in Missouri were tailings dams.

Jan 1, 1987