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By Doug Brown

The recent expansion of our cities into hilly areas, particularly on the Pacific Coast, has resulted in damage or destruction of many homes due to geological problems such as landslides, soil creep, erosion, subsidence, or groundwater seepage. In southern California, landslides are the principal cause of damage and attention is focused on them. Landslides have occurred due to the reactivation of old slide masses, or have been caused by grading and increased water, infiltration resulting from development.. Reactivation of a portion of the ancient Portuguese Bend landslide in Palos Verdes, Los Angeles County, affected approximately 150 homes. A common type of new failure' occurs when grading has undercut bedding or other essentially planar surfaces so that they dip unsupported out of slope. Other slides have occurred due to the inherent weakness of the material involved. Preventive measures undertaken to eliminate damage in the southern California area have. included areal geologic mapping programs-in-advance of development, enacting or strengthening grading codes, and requiring extensive studies by consulting geologists and soils engineers both during the design stage and during construction. In the design stage, proposed cuts are frequently flattened, lowered or reorientated. Frequently, due to the high cost of land, they are supported by compacted fill buttresses. As a result of these measures, the geologic environment has a major effect on the feasibility, design, and development of, a very substantial percentage of tracts or individual homes.

Jan 1, 1967

By Nicholas Tabor, Norbert Fuegenschuh, Richard Taylor, Jean-Marc Wehrli

The Plymouth Tunnel forms part of the 16-mile long route of the Purple Line Light Rail Project promoted by the Maryland Transit Administration. The tunnel is approximately 1,220 feet in length with a shallow vertical alignment located beneath a residential area. Challenging mixed ground conditions included surficial soils, decomposed Saprolite, and highly weathered to fresh rock requiring the use of the Sequential Excavation Method (SEM) for construction. This paper discusses innovative approaches implemented during construction as well as challenges faced during planning and installation of a spray-applied permanent concrete liner.

Jun 13, 2021

By Miguel Carrera, Jose Arnal, Julian Ortiz, Maarten Haest, Fouad Faraj

ShovelSense is a complete solution for bulk ore sorting at the mine face that combines robust shovel bucket mounted X-ray fluorescence sensors, with real-time material classification, fleet management integration and supporting cloud-based data infrastructure, to ensure each truck always goes to the right destination. Correct truck destinations are a challenge in many current mining settings because the material classification of a truck, which is the key input into the truck destination, is often based on estimates at block resolution (~20x20x15m), with limited adjustment for blast movement and mixing. In this contribution, we present a geostatistical, data driven approach to estimate the potential value of bulk ore sorting at the mine-face for seven open pit mines. The approach is premised on the assumption that truck loads within blocks follow a simple gamma distribution. Standard ore control data from the seven mines have been used to estimate the potential bulk sorting value at these operations and ShovelSense-integrated dispatch datasets have been used to validate these estimates for specific benches on which ShovelSense operated. ShovelSense results validate the ore control data-based value predictions and show how at mine-face bulk ore sorting value varies between distinct deposit types. In general, deposit types that have higher bulk ore grade contrasts, display more potential ShovelSense value. The manuscript concludes with the limitations and opportunities of applying the proposed value estimation approach to evaluate at mine-face bulk ore sorting opportunities for open pit operations.

Jun 25, 2023

By Maurice L. Madden

An investigation was undertaken for a ground water discharge plan for the Chino mining complex near Hurley, New Mexico. Operations which impact ground water include dump leaching, storage reservoirs, and tailings seepage. The investigation included both hydrogeological data collection and laboratory analysis. A conceptual understanding of surface water and ground water was then developed. Surface water and ground water models were used to match existing conditions and predict the impact of operational modifications. The study concluded that runoff and resulting leach reservoir overflows were primarily responsible for the ground water degradation. Tailings seepage represents a smaller part of the impact.

Jan 1, 1984

By Qiong Wu, Qinghua Gu, Yichuan Lv, Jin Yuan, Caiwu Lu

"The cut-off grade is one of the important parameters of mining production. Different material cut-off grade is directed to different destinations. Based on reasonable and optimal cut-off grade, long term mining plan and investment decision analysis can be made for mining managers. In view of multiple-metals open-pit, the paper has proposed that multiple-metals cut-off grade optimization model is set using the objective function to maximize net present value (NPV). The method of equivalent coefficient calculation is proposed to convert multi-metals cut-off grade optimization to a single metal cut-off grade optimization. Then the optimization model is applied in a molybdenum and tungsten large open-pit mine in china. The parameters of concentrate price are calculated by PRT in the model and the curve of grade-recovery rate is analyzed and studied according to actual production data. Based on 3D metal deposit model, the distribution of grade-tonnage is analyzed. At final step, an optimal cut-off grade is proposed to guarantee to maximize NPV. The example shows that the model of multiple-metals cut-off grade optimization can provide reasonable analysis for optimal multi-metals cut-off grade and develop optimal production strategies. Introduction Cut-off grade is one of the most important parameters in metal ore mining because of its influence on the overall economic profit of mining production. Along with the development of the mining production, dynamic optimization of cut-off grade is necessary through the analysis of technical economy. It is better to manage the mining production according to the variation of market. The cut-off grade plays an important role in mining production."

Jan 1, 2017

By John Newby, Ulf Gwildis, Fred Marquis

From the Brightwater Conveyance System in Seattle to the Second Narrows Water Supply Tunnel in Vancouver, BC, the design and construction of deep-lying tunnels in the Pacific Northwest often require the incorporation of deep portal shafts. Alluvium overlying marine and glacial deposits combined with the high regional seismicity is the common geologic setting. The latest example illustrating the development of shaft design for this scenario is the 40-m-deep shafts of the Annacis Island Wastewater Treatment Plant New Outfall System. The main components of the shafts include the initial lining, providing the excavation support system to be used for launching and receiving a 5-m-diameter TBM; and the final lining, designed to withstand all static and seismic loads and to remain viable for the intended design life. This paper presents design and construction considerations for these shafts against the background of and lessons learned from past project experiences.

Jun 13, 2021

By George K. Martin

This paper deals primarily with roof bolting in Kentucky coal mines from January 1, 1949, through December 31, 1954, a six year period. The Consolidation Coal Co? (Ky.), a division of the Pittsburgh Consolidation Coal Co., began systemmatic roof bolting in November 1948 in Mine #204, Elkhorn #3 Seam, at Jenkins, Kentucky, After the efficiency of roof bolting had been proven by the Consolidation Coal Co., this procedure was adopted by other companies throughout the state. In December 1954, approximately 46.4 percent of Kentucky's total production of coal from underground mines was obtained from roof-bolted areas. Statistics in this report will show the progress made in roof bolting during the six years, in addition to the roof bolting being done as of December 31, 1955. Significant progress has been made in the coal mines of Kentucky in reducing the roof-fall fatality, rates, during the past several years by adopting systemmatic roof bolting. The ground work by the Consolidation Coal Co, (Ky.) in cooperation with the Federal Bureau of Mines was based upon the previous experience of the St. Joseph Lead. Cc, in its Southeastern Missouri Mines and The Tennessee Coal and Iron Division of the United States Steel Corporation. The author gratefully acknowledges the cooperation and assistance given by officials of the various mining firms using roof bolts, the Kentucky Department of Mines and Minerals, and the Federal Bureau of Mines in furnishing photographs and information.

Jan 1, 1958

By M. E. Rossi

Reconciliation of production information is critical to evaluating the effectiveness of the predictive models, and to allow for optimization of mining operations. Whether mining open pit or underground, mine-to-mill reconciliations can be one of management's better tools to perform proper accounting, and a very useful evaluation and optimization tool. This paper proposes a set of criteria and objectives for a typical reconciliation program; also presents a stepwise, logic approach to performing reconciliations, and discusses the benefits and costs associated with the up-keeping of the information. It also highlights some of the potential pitfalls involved, and methods used to avoid collecting misleading information. These issues are illustrated with an example of a model-to-mine-to-mill reconciliation program being implemented at an operating mine; the program involves multiple predictive models (Long-term and Short-term block models), different open pit and underground mines, stockpiling, and at least 23 different mill streams. This paper presents the initial results of the program implemented at Minera Michilla S.A.

Jan 1, 1999

By Masaji Kato, Yuusaku Tominaga

To maintain good condition of ventilation for both safety and economy, many regulators are installed in a network. In case the open state of a regulator is different from the set point, identification of a broken regulator and a countermeasure to recover airflow distribution in a network must be initiated as soon as possible. An experienced mining engineer can sense a deviation from ordinary airflow quantity. In this paper, a new system to monitor all the regulators in a network is introduced. The basic concept of the system is utilization of both human sensing of airflow rate and computer simulation to understand the macroscopic characteristics of a ventilation network. A fuzzy pattern distinction method is used to process human determination of airflow rate that may be ambiguous. The applicability of the system is demonstrated using the ventilation network of the Horonai coal mine, Japan. In particular, it is shown that the system can identify the regulator to be repaired from information supplied by workers relating to air- flow in a few sensor branches.

Jan 1, 1997

By Lloyd M. English

Accurate knowledge of the gas content of coal seams has always been important, according to the work of W. P. Diamond and J. R. Levine, 1981, but is becoming increasingly important for several reasons: Excessive gas emissions in the mine can create explosion hazards. Depletion of shallower coal reserves is forcing underground operations to greater depths where coal gas content is often greater. Natural gas prices and the need for new energy sources make naturally occurring coal gas a potential resource of economic interest. Information on coal gas content will impact mine designs, mine ventilation system specifications, and the effectiveness of methane control procedures used. Accurate resource assessment is needed for projecting and designing potential gas utilization enterprises. The emphasis upon methane hazards in mining operations, and upon potential methane utilization, has led us to improve upon the procedures used to determine coalbed methane levels.

Jan 1, 1984

By F. S. Knoll

Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, separating halite and sylvite, and shape separation of vermiculite and gangue minerals. Electrostatic separation techniques are based on one of two methods, electrophoresis or dieleccrophoresis -- processes involving charged and uncharged particles respectively. In some cases, the combination of these two techniques has proven quite useful. The purpose of this paper is to provide a basic understanding of the physical processes collectively called "electro- static separation" in order to enhance one's ability to define and consider new possibilities in mineral processing and other fields.

Jan 1, 1984

By Richard P. Curtin, Madan M. Singh, Francis S. Kendorski

INTRODUCTION The use of roof and rock bolts to reinforce the strata is an established method of rock support in both underground and surface excavations. However, the need to drill a hole, extract the drill-rods, and then place the bolt is time-consuming and costly. This becomes even more significant if the bolting is repetitive and extensive as in coal mining. Though the main thrust of this development was directed towards coal mining, the basic concepts are also widely applicable to all excavations. The authors, therefore, feel that this innovation should be of interest in rapid excavation and in tunneling. In the case of coal mining, it has been established from past statistics that the roof-bolting operation is the most hazardous activity. This is primarily because of the operator being exposed to unsupported ground. It is evident that remote installation of roof bolts would markedly improve the safety of the operation, if accomplished more readily with self-drilling bolts rather than the conventional two-step variety operation. Thus, in addition to increasing productivity, this development can be considered to be a milestone towards further improvements. The objective of this program was to establish the technical and economic feasibility of self-drilling roof bolts for use in coal mines. It might be clarified at the outset that this work was, therefore, directed primarily at showing that workable self-drilling bolts with less cost can be developed, which could be effectively used in mines. It was not to fabricate a production model bolt.

Jan 1, 1979

By Dana A. Echter

The Paso Diablo coal project is located in the Guasare Basin in the northwestern region of Venezuela near the border with Colombia. In 1987, Carbones del Guasare SA, a joint venture comprised of Carbozulia and A.A. Antilles Coal (an Arco and AgipCoal joint venture) was formed to develop the Paso Diablo coal reserves for world markets. Regional drilling has indicated a coal resource of more than 6 Gt (6.6 billion st). Further exploration has delineated the Paso Diablo deposit as an area particularly suited for cost-effective surface mining. The calculated economically minable reserves of this area (200 Mt or 220 million st) and the coal quality characteristics are based on extensive core drilling programs. Initial coal mining operations began in August of 1987 and the mine is presently producing at a rate of 1.5 Mt/a (1.65 million stpy). The coal is hauled about 85 km (53 miles) to a barge loading terminal at Santa Cruz de Mara using highway-type haul trucks. When the coal reaches the terminal, it is loaded into barges and then transloaded onto ocean-going vessels with barge mounted

Jan 1, 1990

By J. S. Lewis

Beneficiation and physical and chemical processing of non-terrestrial materials borrow strongly from terrestrial experience, but also involve the necessity of handling literally un-Earthly feedstocks, reagents, and environmental conditions. The present state of scientific and engineering understanding of the processing of non-terrestrial minerals, gases and hydrocarbons is reviewed with the production of rocket propellants, life-support fluids, structural metals, and refractories as the goal.

Jan 1, 1992

By Alan R. Johnson

Because of the competitive nature of the iron ore pelletizing industry, commodities required for the production of pellets are continually being scrutinized to minimize their usage and offset rapidly escalating costs. In the Tilden pellet plant, the usage of one commodity, bentonite, has been reduced from over twenty-four pounds per long ton of pellets to as low as eight pounds per long ton. The evolution of bentonite usage from plant start-up to the present time is described.

Jan 1, 1984

By Ken E. Baylis

Current over-capacity in coal production provides assured and relatively low-cost supplies to coal importers. At the same time, it is of serious concern to coal producers who invested considerable sums in the expectation that overseas demand would continue to grow rapidly. This paper assesses the reserves available for export, the export facilities, the coal supplies which can be put through them, and the market prospects for the future. It assumes, rightly or wrongly, that there will be no major and prolonged disruptions in supply from any major sources of coal. COAL RESERVES FOR EXPORT Economically recoverable reserves in the non-communist world amount to about 470 billion tonnes. These are sufficient to sustain current production levels of 2 billion tonnes a year for 235 years.

Jan 1, 1984

By M. E. Mellado

In this paper, we present an a posteriori validation of a heap leaching analytical model using sensitivity analysis. The model is suitable to represent the process of heap leaching of solid reactants from porous pellets and is based on a combination of the leaching kinetics at two levels: particle and heap. The validation is simple, and a sensitivity analysis can easily be performed. The simplicity of the analysis provides insight into the control and optimization of the heap leaching process without strong mathematical complexities. The model and the corresponding sensitivity analysis include the effects of heap height, particle sizes, flow rates and several operation-design variables. Using a case study, we discuss the importance of model validation based on sensitivity analysis. We also comment on several choices for optimizing the process. We had three goals in this work: a posteriori validation, highlighting the importance of model validation and providing insight into optimization choices. We can conclude that the model has good internal logic and there are no extra variables; i.e., all of the variables in the model are necessary.

May 1, 2012

By B. I. Pålsson, H-Å. Häggblad, J. F. Stener, P. Jonsén

"Understanding mill charge motion is important. In the charge, the center of gravity is shifted from the rotational center of the mill system, and its motion is induced by rotation of the mill. At the same time, the charge creates a torque in the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to this motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty of measuring inside a tumbling mill. Experimental measurements in a lab mill were done for a number of load cases: varying feed material, mill filling, mill speed and pulp liquid. The mill is set up to measure the charge-induced torque. The accuracy is good, with relative uncertainty less than ± 2% for relevant load cases. A full three-dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill startup behavior for torque and mill power. This proves that the model is physically correct, and can be used for modeling large-scale mills.IntroductionUnderstanding of the charge motion within the mill is of importance in mill optimization. The breakage of ore particles and the wear of liners/ball media are closely linked to the charge motion. To study these phenomena in a physically correct manner, appropriate numerical models for different parts of the mill system must be used. Validation of these models is of major importance. This has led to an increased interest in obtaining an accurate and direct measurement of mill load and the behavior of the mill charge.For structural analysis, the finite element method (FEM) is the most developed and most frequently used numerical method. FEM is a numerical solution method based on continuum mechanics modeling. A constitutive relation for the actual material is described, and the governing equations are solved in Zienkiewicz and Taylor (2000). Varieties of different constitutive models for a large number of materials are implemented in modern FEM code. The computability of nonlinear problems in solid mechanics is investigated in Belytschko and Mish (2001), among others."

Jan 1, 2015

By Thomas J. Regan

The first stage of the Massachusetts Bay Transportation Authority's Red Line Extension Northwest, is a two-track rapid transit extension from Harvard Square in Cambridge, through three stations, to the Alewife Station/Garage complex in North Cambridge. The extension, about 5.0 km. (3.1 miles) in length, is entirely in tunnel, with the Alewife Station/Garage complex and adjacent line sections of tunnel constructed by cut-and-cover methods. The Station/Garage complex, just west of Alewife Brook Parkway, is in an area underlain by deep deposits of very soft highly sensitive clays. It is proposed to construct the station and adjacent tunnel sections by the slurry trench method, using the slurry wall as the permanent structural wall of the station and tunnel. The unusual nature of the underlying clay and its very high sensitivity raised questions concerning the feasibility of the proposed construction. Since research failed to reveal any construction precedent for the specific conditions encountered, a test section was undertaken to determine construction problems, resolve uncertainties, and to establish acceptable parameters for the construction of the slurry walls. PROJECT ORGANIZATION Sverdrup & Parcel as tunnel and transit systems consultant for the Red Line Extension-Davis Square to Alewife had overall responsibility for determining program objectives, project management and test implementation.

Jan 1, 1979

By Mohammad Irshad, Larry H. Heflin

INTRODUCTION The planned 166 kilometer (103 mile) Metro rapid rail transit system in Washington, D.C. is being designed and constructed by the Washington Metropolitan Area Transit Authority. At the present time, 112.6 kilometers (70 miles) of this system is in operation and contains 21 route-kilometers (13 miles) of rock tunneling, and 14.5 route-kilometers (9 miles) of soft ground tunneling. An additional 2.4 kilometers (1.5 miles) of single track tunnels in rock are planned and 6 additional contracts will consist of some 8 kilometers (5 miles) of twin tunnel, resulting in 16 additional linear kilometers (10 miles) of single track tunnel in soft ground. The Authority plans, upon its evaluation and the recommendation of the General Engineering Consultant, to include an alternative design incorporating the convergence confinement method of construction known as the New Austrian Tunneling Method (NATM), for Sections E-5, E-6e and E-8a of the E-Route. The Metro system is constructed in a variety of geological conditions and crosses the boundary of two major geographic provinces. Rock tunneling is to the west of this "fall-line" boundary, soft ground tunneling to the east. The soft ground tunneling portions of Metro construction lie in the coastal plain which consist of a

Jan 1, 1987