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By Mollie Hunt, William Riley, Russ Downer, Kate Willa Brown Requist, Víctor O. Tenorio, Geoffrey Gill

One of the first activities after returning to the Moon will be finding sources of water and materials for the construction of human settlements and other infrastructure. There is evidence of the existence of deposits in the bottom of craters at the South Polar region and in flat areas around. Based on geological data from the Moon, a block model representing a deposit or icy regolith has been defined in the vicinities of Shackleton Crater, with unique characteristics of shape, thickness, and water contents. A mine plan utilizing surface mine modeling software for ore extraction from an open pit- type of excavation to a delivery point near a water processing facility is proposed, with monthly, quarterly, and yearly schedules. Production results, dashboard charts and progress of the topographic changes are also presented.

Feb 1, 2024

By Sergio Flores, Nate Long, William Hodder, Phil Rhodes, Tim McQueary

The Surface Water Supply Project Segment B3 is a 4 miles section of tunnel that will run East- West in Houston TX, from Hopper St to I-45. The tunnel will be mined by using a 128" Dia refurbished 1987 Lovat Tunnel Boring Machine capable of operating in Open or EPB mode. The tunnel will be temporarily supported with ribs and lagging and a 96" Dia pipe will be grouted into place. All four miles of this project are within Petroleum Pipeline Easements. The project includes seven shafts, 2000' of tunnel in potentially petroleum contaminated ground, crossing the Hardy Toll d, I-45, the nion Pacic ailroad ight of Way and multiple oil and gas pipeline crossings. This paper summarizes the planning and drive performed to date.

Jun 23, 2024

By Rodrigo Peroni, Euler Victoria

Knowing the depth of contacts between weathering zones in phosphate mines is determinant to define the stripping ratios and the mineralized zones. Contacts are gradational and difficult to define even in the drillhole samples, so the combination with geostatistical simulation techniques helps to define the contact zone and the grade distribution, providing a way to assess the probability of the occurrence and the positioning of contacts between the barren waste and the ore zones. These inputs are used in the scheduling, anticipating risks associated with mine planning scenarios. The results from an application to a case study showed a good improvement when compared to traditional techniques.

Jun 25, 2023

By T. W. Camm

The Bureau of Mines conducts studies of the economic impacts of regulations on federal lands. These studies are part of the Bureau Potential Supply Analysis (PSA) program. To meet the needs of these studies, a methodology was developed to estimate operating and capital costs for a mineral deposit given its tonnage, grade, and depth. The format for the cost models in this study was developed at the Bureau's Western Field Operations Center (WFOC), Spokane, W. A., for studies of known and undiscovered resources on Federal lands. These cost models are described in a Bureau publication by Camm (1991).

Jan 1, 1993

By C. D. Elifrits

The required reclamation of land disturbed by surface coal mining often results in the creation of some over steepened slopes which are prone to rapid erosion and sediment production. This natural activity on such slopes is not desirable nor allowed under current regulations. Experience has indicated that novel approaches must be devised to address the problem. Research conducted on field sites in Missouri has indicated that construction, during the reclamation and grading processes, of a man-made drainage system will control the erosion. The drainage system must replicate or exceed the natural system in terms of drainage density and channel frequency. Basic design considerations will be summarized in this paper and field results shown.

Jan 1, 1986

By Roland W. Merwin

The Bureau of Mines has studied the possibility of using the heap leaching process for treating the gold ores in the sedimentary beds of northeastern Nevada. This paper summarizes all available information on the technical and economic feasibility of heap leaching oxidized ores from these beds, past industry application of vat leaching, results of recent Bureau of Mines and industry tests on heap leaching ores from this region, and requirements for planning the proper application of heap leaching. Preliminary tests on representative samples of ores from the region show that a satisfactory recovery of gold can be obtained by heap leaching the ores with cyanide at a relatively coarse size. Significant deposits of gold ore occur in sedimentary beds of various locations over an extended area 40 miles wide and 200 miles long in northeastern Nevada. The area is centered 40 miles west of and runs parallel to the leading edge of the Roberts Mountain thrust fault system, a prominent geologic feature in the area. The general locations of past and present gold mining operations are shown in figure 1. (slide 1)

Jan 1, 1969

By Herman Gill, Dani Delaloye, Madelyn Rubin

The Foothill Tunnel is a remote 16-mile-long untreated drinking water tunnel in the San Francisco Public Utilities Commission’s (SFPUC) Hetch Hetchy Water and Power (HHWP) system. The 14-foot horseshoe shaped tunnel, constructed in the 1920s, is lined intermittently with concrete over approximately 53% of its length, with the balance being unlined rock. After detailed planning, in January of 2020 Mott MacDonald and HHWP staff completed a visual inspection and documented the condition of the tunnel with electronic data collection, photographs, and video with audio recording. The result was a comprehensive condition assessment that identified key areas of the tunnel to monitor.

Jun 13, 2021

INTRODUCTION The role of comminution and related unit operations in mineral processing applications is of major importance. This is especially true in terms of operating costs, since these unit operations represent the major fraction of the overall processing costs. Due to the broad scope and the large number of unit processes and machines involved, Section 3 is divided into five subsections. In Section 3A, General Aspects of Comminution, topics covered include history, terminology, particle¬size distributions, classes of comminution machines, testing and calcu¬lation procedures, and simulation and modeling. In Section 3B, Crush¬ing. the subjects include jaw crushers, gyratory crushers, cone crushers, hammermills, and impactors. The chapters of Section 3C, Grinding, cover aspects common to tumbling mills, ball mills, rod mills, autogenous mills, pebble mills, roller mills, fluid energy mills, other types of grinding machines, and grinding costs. Section 3D, Classification, coverage includes classification theory, hydrocyclones, and mechanical classifiers, and in Section 3E, Screening, the topics presented are classes of screens, selection of vibrating screens, sieve bend screens, and screening media. About five years after the Handbook was begun, Section 3 was unfortunately without an editor or contributors for over half of the chapters. A committee was then organized to expedite completion of the section. When this committee contacted the persons who had agreed to contribute to the section, it was found that many of them wished to resign from their earlier voluntary obligation to AIME. Therefore the committee had to find new contributors for these chap¬ters in addition to other chapters in Section 3. Since there had been no previous effort to locate contributors for Air Classification, Dust Collection, and Washing and Scrubbing, it was agreed to delete these subsections. In Section 3, equipment availability, capacity, and performance data from various manufacturers and users are provided for engineer¬ing use. Selected data from existing installations are also included. The machines that are being used in comminution, classification, and screening are described in detail, and drawings, photographs, and diagrams are presented to supplement the descriptive material. The editors thank and acknowledge the generous effort of the many contributors, some of whom were called upon five or more years after the Handbook was started. It is regretted that Fred C. Bond, who was a member of the committee formed to complete this section, was deceased before the section was finished. During the time that he worked with the committee, he contributed a great deal as an author and councilor.

Jan 1, 1985

"During his presentation at the 2016 George A. Fox Conference about the history of public-private-partnerships (PPP) in the tunneling and underground construction industries in New York, Vincent Tirolo, Jr., told a story about how, as a young engineer in the late 1960s, he and others pooled money to purchase a calculator for $75 that had the ability to perform sine and cosine functions. That was a big deal in those days and would make their job much easier. Oh how far things have come. Tunnel and underground construction engineers can now virtually map out and plan entire projects before the first shovel ever breaks ground. And the machines that are used to build the tunnels have advanced in ways that could not have been imagined 50 years ago.The calculator is just one example of innovation in the industry and on Jan. 26, more than 400 industry professionals attended the George A. Fox Conference at the Graduate Center of New York (CUNY) to learn more about the next innovations, new tunneling technologies and what the future might hold for the industry. The conference included sessions on contracting models, rescue and fire life safety and new technological developments as well as an international project spotlight presentation from Nasri Munfah about the Eurasia Tunnel, connecting the European and Asian sides of Istanbul, Turkey.The project, also known as the Istanbul Strait Road Tube Crossing project, was named the 2015 Major Tunneling Project of the Year by the International Tunneling and Underground Space Association.The tunnel boring work for the 3,344-m (11,000 ft) long tunnel under the Istanbul Bosphorus Strait was completed in August, heralding a new era in tunneling.Tunnel boring work was launched in April 2014 with a ceremony with then Prime Minister Recep Tayyip Erdogan in attendance. The work was completed on Aug. 22, 2015 with Prime Minister Ahmet Davutoglu participating in the ceremony."

Apr 1, 2016

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

1.1 INTRODUCTION When underground mining involves total extraction, it induces overburden strata movements. If not properly planned it causes surface subsidence and affects surface environmental conditions. Total extraction usually refers to longwall mining and room and pillar mining with pillar extraction. Surface subsidence has long been a subject of intensive research for scientists all over the world and considerable achievements have been obtained. However due to its difficulties and complicated nature, research into overburden movement has been thus far incomplete as compared to that into surface subsidence. Since surface subsidence is a manifestation of the results of overburden movement, the processes and mechanisms of overburden movement must be fully understood in order to establish the mathematical prediction models of surface subsidence. In this chapter the processes of overburden movement and its zones of movement in the overburden will be discussed. 1.2 PROCESSES OF OVERBURDEN MOVEMENT When total extraction is used, it produces a large void in the coal seam and disturbs the equilibrium conditions of the surrounding rock strata. The roof strata bend downward while the floor heaves. When the excavated area (or gob) expands to a sufficient size, the roof strata will cave. As a result, the overlying strata continue to bend and break until the piles of the fallen rock fragments are sufficiently high to support the overhanging strata. At this tie the overhanging strata no longer cave, but bend and rest on the underlying strata. Strata bending and subsidence develop upward until reaching the surface and forming a subsidence basin. The whole overburden strata and the surface subsidence basin will further go through a period of compaction and gradually become stabilized. Current knowledge regarding the process of overburden movement has been derived from several sources. One is the direct observation of the mined sections and their surfaces, another from field monitoring of strata movements in the overburden, and others from computer modeling and scale modeling in the laboratory. For example, Figs. 1.1 and 1.2 show the results of a borehole monitoring experiment (Borehole B-2) using the full profile borehole inclinometer and full profile borehole extensometer for lateral displacements and vertical subsidence, respectively (Conroy and Gyarmaty, 1983). The panel, 400 ft wide by 5000 ft long and 630 ft deep, was extracted from the Pittsburgh No. 8 seam which had an average thickness of 54 in. The face advanced from east to west. Curve A in Fig. 1.1 shows the inclination of the borehole when it was 45 ft ahead of the face at Position A (i.e., on the solid coal side). The total deviation of the borehole was 1/7000. The first shear movement occurred at 130 ft above the coal seam and appeared to have occurred along the bedding plane with large contrast of rock strata on both sides, i.e., sandstone vs. shale. When the face had passed the borehole 79 ft at Position B, the borehole deformed to assume a bow shape with a maximum deviation of 2.8 in. from the center line. Numerous shearing planes occurred and extended further upward. When the face had passed the borehole by 75 ft at position C, strata subsidence was measured. Fig. 1.2 shows that a strata separation as large as 4 ft occurred at 40 to 100 ft above the coal seam. Above this level, the strata subsided more uniformly with bedding separations within 1 to 2 in. Another example is the longwall mining with complete caving in the Soviet Union's Karaganda Coalfield (Kolebaeva, 1968). The coal seam was 6 ft thick and 154 ft deep. The immediate roof was the fine-grained sandstone interbedded with coarse-grained sandstone. Above this, there was sandy shale and shale. In order to monitor the process of overburden movement, 15 stations were established in a borehole (Fig. 1.3). The elevations of those stations were measured when the face was at various distances from the borehole. Fig. 1.3 shows the movement history of each station. For convenience of comparison, the movement history of each station was plotted on a common reference point as shown in Fig. 1.4. Clearly, the movements of strata from Station # 1 to #6 were nearly simultaneous, i.e., they behaved as a single unit. The strata from Station #7 to # 15 had differential separations, the maximum of which was 40 in. As the face passed by and moved away, strata separations in general reduced gradually. But strata separation between Stations #12 and #13 remained the same until the end of the monitoring period. The total bed separation between Station #7 and # 15 reached 11 in., approximately 18% of seam thickness, when the face was 132 ft beyond. Based on the above observations, the author developed a conceptual model of overburden movement due to underground longwall mining (Fig. 1.5). The above-mentioned two case studies illustrated that subsidence in the overburden strata propagates upward and subsidence velocity decreases from the bottom to the top. When the subsidence velocity at the surface reaches the maximum value, the subsidence velocity at the bottom portion of the overburden strata has decreased considerably and the strata have begun to compact. Bed separation occurs within a certain distance above the coal seam and reduces from the bottom to the top. When the face has moved away, bed separation reduces gradually, so that eventually some beds completely close and others partially close. Bed separation reaches the highest level when the subsidence velocity at the surface is at its maximum value. For instance in Fig. 1.4 surface subsidence velocity was maximum when the face was 38 to 44 ft past the point. At this time the total bed separation was maximum. Overall the strata directly above the opening are subjected to tension in the vertical direction. But above a certain level, all strata move nearly simultaneously. There is also significant shear movement along some bedding planes. 1.3 ZONES OF MOVEMENT INTHEOVERBURDEN After the extraction of a longwall panel or room and pillar section of sufficient width the strata in the overburden are subjected to various degrees of movement from the bottom to the top. According to the movement characteristics, the damaged overburden can be divided into four zones (Fig. 1.6). Caved Zone. After the extraction of coal, the immediate roof caves irregularly and fills up the void. The strata in this zone not only lose their continuity completely, they also lose their stratified

Jan 1, 1992

By J. Litsenberger, T. E. Marshall, L. Burke, R. Melville, A. T. Iannacchione

Excessive levels of horizontal stresses cause ground fall hazards in underground mines in the Appalachian Basin. At an underground stone mine in Pennsylvania, a modified stress control mine layout is reducing the hazardous conditions associated with excessive horizontal stresses. A microseismic monitoring system is in place to measure levels of rock stability and provide information on the effectiveness of the design technique. The microseismic data is supplemented with frequent and extensive mapping of roof falls and roof rock damage. Findings to date show that the stress control layout provides more stable conditions and thus a safer environment for the mine workers.

Jan 1, 2001

By R. Mensah-Biney

The kinetics of gold-bromide loading onto activated carbon has been investigated in a batch stirred reactor. The amount of gold adsorbed by the carbon was correlated with time based on a second-order equation. The rate constant for gold-bromide species onto activated carbon ranged from 0.27 to 1.2 x 10-3 (kg/t)-l(min)-l from a solution containing 25 ppm of Au, with 0.8 g carbon per liter of solution at 30° C. The equilibrium saturation capacity (Q.) was 36±3.0 kg/t from the same system. The rate of loading increased with decreasing particle size, decreasing pH, increasing temperature, and decreasing concentration of gold in solution. The calculated activation energy E. was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Q.) increased with increasing concentration of gold in solution, but was independent of other variables such as temperature, agitation speed, particle size and pH. These rate constants and equilibrium saturation capacity for the gold-bromide species are higher than those reported for the gold-cyanide systems.

Jan 1, 1996

By S. Lin, Y. J. Wang

Fan stall is a notorious phenomenon of axial flow fans. When multiple fans of this type serve a ventilation system, their mutual impacts on the stability of the ventilation system are very complicated and not well understood. Results from laboratory experiments indicated that, when a fan is working across its stall zone (i.e., the pronounced trough on the fan characteristic curve), some branches in the system may suffer abrupt and even drastic changes in air quantity and pressure. The quantity range of the fan that causes the abrupt change is called an unstable operating range. The corresponding quantity range of a branch is called a nonachievable quantity range of the branch, because any quantity within this range cannot be achieved without changing some parameters of the ventilation system (e.g., branch resistances). This paper discusses these important characteristics of ventilation systems by using results from tests on laboratory tubing networks.

Jan 1, 1998

By G. Brofas

The reforestation potential of bauxite mining spoils by seeding was examined on this research work. The experimental plot was established on the location Strofi Koukouvista 5, Ghiona Mountain. The experiment consists of 3 species (Pinus nigra, Robinia pseudoacacia, and Spartium junceum) with 4 sowing treatments and 2 sowing seasons (autumn and spring). The treatments were: (1) broadcasting; (2) broadcasting and soil cultivation; (3) broadcasting with straw mulching and straw binding with asphalt emulsion; (4) broadcasting with soil cultivation, straw mulching and straw binding with asphalt emulsion. Third year results show that spring is better than autumn as a sowing season. Only the Spartium junceum species were found to germinate and survive in autumn. The results are better for all the species on the spring seeding. The most effective treatments for Robinia pseudoacacia and Pinus nigra are 3 and 4 while for the Spartium junceum even simple broadcasting shows good results although the best ones are achieved with treatments 2, 3 and 4. The paper?s findings show that reforestation by sowing could be effective for some species but further experimentation with other species is recommended. Concerning Robinia pseudoacacia, testing of different seed preparation treatments is needed in order to maximize the germination of seeds.

Jan 1, 2002

By T. E. Scartaccini

A drill recorder is a permanent data collecting instrument. In open pit blast hole drilling the application of a drill recorder is that of data collection, drilling control, and drilling education. The various drilling parameters (weight, RPM, penetration, torque, and air) have a drilling correlation which can be demonstrated and documented by a recorder graph. When the correlation is physically put to use during the process of drilling, then the recorder has become a drilling tool and is no longer just a data collecting instrument, per se. By being able to maintain accurate records and drilling control, comprehensive studies of changes both operational and technological can be made. These are based on in-progress facts and not after-the-fact logs. To determine total drilling efficiency, drilling conditions must be documented and controlled. Field operations at American Smelting and Refining Company's Mission Mine have proved that by increasing drilling control, demonstration of parameter relationships, and drill monitoring, more economic efficiency can be obtained. In comparing results obtained with recorder control and conventional control a decrease of 14 percent to 36 percent of drill footage costs were obtained. The percentage of variance is dependent upon whether drilling is milled-tooth or carbide-insert bit drilling.

Jan 1, 1970

By Barrie C. Butt

The opportunity for an exploration geologist to follow a successful exploration project through the feasibility, financing, construction, development and exploitation phase is rare. In addition, it is not often that the exploration geologist can be present during the mining of a deposit to explain why certain actions were taken or interpretations made and to find out how these interpretations turned out in actuality. At the Woodsreef chrysotile asbestos mine in New South Wales, Australia, mining has been in progress for six years and the writer has been intimately associated with the project during the five years of exploration and the six years of exploitation. The industry is possibly aware of the fact that the Woodsreef Mine has had major production problems, the majority of which have stemmed from the unique characteristics of the ore body and of the fibre. Because of these unique features, a large volume of research has been undertaken by Woodsreef and by other scientific organisations in Australia, England and Canada on the Woodsreef fibre. The answers to some of the problems have negated some semi-sacred concepts of asbestos ore milling and led to the development of new techniques, such as the adoption of microscopic fibre counts as a routine procedure; the modification of accepted evaluation procedures; the development of new machines for dedusting fibres, and to the recognition of a fibre with a unique milling behaviour pattern and, possibly, properties. The problems experienced can be divided broadly into those associated with the geology and those associated with the physical properties of the fibre. It is possible that the same features may manifest themselves in other deposits around the world, and if they can be recognised during the exploration stages a feasibility evaluation may be just that little closer to the actual.

Jan 1, 1978

By James R. Jones

The tempo of air pollution control regulations has increased dramatically in the past few years. Because coal mining operations are frequently located in remote areas away from urban developments, specific regulations applying to coal mines have received lower priority and are thus only now being promulgated and/or enforced. Therefore, many mine operators are not yet familiar with the regulations and the impact upon their method of operations. Few have been faced with an inspector on the property sighting them for specific violations. Several of the Mid-western states are just now requiring permit applications to be submitted.

Jan 1, 1973

By A. R. Hollbach

This paper presents a succinct overview of the Canadian coal situation. The topics treated specifically are: the rates of growth of coal supply and demand; the relationship between the coal and electricity generation industries which form its dominant market; the unique impact of nuclear generation on coal demand in Canada; and finally, a view of the developing technologies which will create opportunities for growth in the coal industry of the future. Resources The most important element of coal supply is the resource. The disposition of Canada's coal resources has a marked effect on their utilization, since industry in Canada has not generally developed around coal-fields. The distance from the major industrial centres of Ontario and Quebec to the major region of coal supply in Alberta and British Columbia has crested an economic barrier to the expansion of the use of domestic coal.

Jan 1, 1985

By K. Lang

A test section of the upper most lift and underlying lifts of a large scale copper heap leach operation was instrumented and monitored with advanced wireline geophysics, fiber optics and resistivity electrode arrays. Elemental Capture Spectroscopy (ESC) copper measurements, resistivity measurements from an Array Induction Tool (AIT), electrical resistivity tomography (ERT) and distributed temperature sensing (DTS) with fiber optics provided integrated near real time data about the performance of the heap. During the leaching cycle, ECS provided continuous vertical measurements of copper in the upper most and underlying lifts in the test section of the heap and was used to generate a copper recovery curve. ERT inversion modeling provided high resolution 3D resistivity measurements, which were used to evaluate moisture distribution. DTS measurements of temperature were used to track the PLS front and calculate velocity. AIT induction provided highly precise bulk resistivity measurements. In-situ samplers provided PLS chemistry at multiple points. Properly integrated monitoring data can provide the heap leach operator with information that can be used to evaluate the hydrodynamics and metallurgy of the leaching process in near real time. Problems in the heap, such as pooling, channeling, longer lag and breakthrough times, excess acid consumption, increased solution in inventory, toe saturation and slope stability can be detected in near real time with the in-situ measurements evaluated.

Feb 23, 2014

By G. W. Luxbacher

Coal mine infrastructure is rarely designed solely on the basis of ventilating the underground workings. Instead the optimization of a mining sequence, the minimization of coal quality variation, reduction of coal losses by adapting to property boundaries and geologic structure (seam inclination, roof conditions, coal thickness, etc.) or other similar considerations have formed the objective for mine plant design and layout. Infrastructure development may also reflect a desire to maximize production early in the life of the mine or to permit flexibility in mining according to market conditions. Requirements for coal mine ventilation, established by the 1969 Coal Mine Health and Safety Act, have mandated changes in the traditional concepts of mine plant design in the United States. Mines, in operation prior to the passage of the Act have experienced severe limitations when attempting to adapt the existing mine infrastructure to meet the requirements of the law. In addition the increased quantities of air required, velocity limitations on trolley haulage and belt lines, the establishment of separate intake escapeways and gob area ventilation have com- pounded the inherent complexity in planning mine ventilation systems. Past practices in mine ventilation planning and design are no longer adequate. Given the complexity of today's ventilation systems, effective planning and design approaches are required. As such, the interrelationship between the overall coal mine plant design and ventilation system design is examined. An approach to ventilation system design constrained by global considerations of mine plant design, is presented. The proposed approach is, however, applicable to the design of new mine ventilation systems as well as to the modification of existing systems.

Jan 1, 1980