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By H. Colijn

The problem of the freezing of moist raw materials, such as concentrates, in railroad cars during winter shipment has been a continuing source of both economic and operational trouble to the industry and to the railroad companies. The difficulties center around the discharging of frozen cargoes into the plant materials handling system. Because of cargo freezing, appreciable delays in car-dumping schedules occur each winter and cause additional expense for demurrage charges and for slowdown of plant operations. In one plant during one winter, a car dumper rated at 40 cars per day could dump only 3 cars per day in bad weather. Delays became so serious one winter, that 500 cars held in the yard became so badly frozen, that they were sent to the southern part of the United States to thaw after they accumulated an average of two months demurrage charges. These delays in car unloading become critical if unit or integral train concept is applied to the movement of raw materials. Anticipated savings in transportation costs through better equipment utilization are largely based on rapid loading and unloading cycles of whole trainloads. If freezing problems cannot be adequately solved, unit train operations cannot be operated to achieve the potentially large reductions in transportation costs. The freezing problem may tend to become even greater in the years ahead, because the unit train concept will allow the trains to run faster and consequently the heat loss will be accelerated due to the larger heat transfer coefficient. A compensating factor, however, will be the shorter travel time. Further, the sources of raw materials being mined are located farther north than before and the ambient temperatures during transit are going to be lower.

Jan 1, 1976

By James L. Evers

Introduction There is a continuing search by government and industry for new mining methods that increase production, improve the working environment, reduce labor intensity, enhance recovery effectiveness, improve the reclamation process, streamline the flow of material, and reduce the unit cost. Hydraulic extraction and transport methods have outstanding potential in several of these areas. For example, hydraulic fragmentation produces a significant reduction in respirable dust. The inherent simplicity of hydraulic mining equipment and the resulting high reliability are recognized. Tool wear can be virtually eliminated. There is great flexibility in the size, shape, and orientation of the mineral deposit that can be mined. The cutting, gathering, and transport operation can be controlled remotely, providing more safety for workers. The threat of tool sparking and the resuiting dust or gas ignition are also eliminated. Although hydraulic mining was introduced in the US before the turn of the century, it has not gained the degree of acceptance found in other countries such as the Soviet Union, China, Germany, and Canada. The Hydraulic Mining Research program, initiated by the US Bureau of Mines in 1958, and the subsequent research by others has provided much of the basic technology required to spur the development of these methods into a viable extraction alternative. This article updates the development of hydraulic mining in the US. Particular attention is paid to monitor mining, the long-wall hydrominer, borehole mining, and the semi-autonomous mining system. Whenever the particular mining method is also being developed in other parts of the world, a brief description of the world-wide state of the art is given. Finally, allied studies designed to optimize these mining techniques are described. Hydraulic Monitor Mining Since 1958, the US Bureau of Mines (USBM), the Department of Energy (DOE), and other government agencies have funded more than a dozen programs to investigate the potential of hydraulic monitor mining. For this method, water is directed on the coal face from a monitor nozzle. Sufficient velocity is used to cause local fragmentation (Fig. 1). Coal particles are washed from the face to a trough. They are then flumed to a collection point. Oversized particles are directed through a breaker and then into the troughs. Monitor field tests were conducted in the 1960s in bituminous and anthracite coal at the following locations: • Rosylin No. 9 mine, WA (Nasiatka and Badda, 1963); • Rosylin No. 10 mine, WA (Price and Badda, 1965); • Sugar Notch mine, PA (Buch, 1964); • Thomson Creek mine, CO (Palowitch and Malinka, 1964); and • West Lebanon, PA (Fowkes and Wallace, 1968). In 1975, Ingersoll-Rand Research Inc. was awarded a two-year USBM contract to develop a continuous coal mining system using water jet fragmentation and

Jan 10, 1984

By Bo Hyun Kim, Mark K. Larson

Although techniques and practices of mining are highly advanced, coal pillar bursts or bumps continue to occur. Many uncertainties remain because of the highly anisotropic characteristics of coal seams that are associated with geologic structure and the mining-induced spatial redistribution of stress in coal pillars. Thus, to prevent fatalities in underground coal mining, continuous efforts are required to better understand the catastrophic failure mechanisms in coal mines. In this study, 3DEC modeling in conjunction with the Discrete Fracture Networks (DFNs) technique was performed to better understand the true anisotropic behavior of the specimens acquired from a bump-prone underground coal mine. The spatial characteristics of the dis- continuities (i.e., cleats and bedding planes) as input data for the 3DEC model are estimated based on the results of the laboratory tests and field observations. The DFNs explicitly generated the coal seam that was poorly or well cleated, indicating the different spacing between cleat apertures using the probability distribution functions for fracture density (or frequency) and size. The heterogeneity of the engineering properties (i.e., cohesion and tensile strength) are also considered by Monte Carlo simulations. Simulation results of laboratory tests using the 3DEC model and DFNs technique agreed well with the results of the laboratory tests. These calibrated results can be used as we seek to evaluate bump risk by modeling at field scale.

Jun 25, 2024

By W. H. Davitt

One might ask why someone like myself, involved in the determination of taxes, should be speaking at a "cost engineering" session of a national engineering society. While it is true that taxes, especially income taxes, whether they be federal, state, or local, are not usually thought of as a "cost" of doing business, it is equally true that these tax costs do reduce the distributable profits just as much, as the cost of power, supplies, or labor. Therefore, the consideration given to taxes is often as important as that given to other costs. Hopefully yea will recognize that, within certain limits, taxes can be controlled to an economic advantage. That question may then lead to another question: What does the amount of taxes have to do with me? I'm an engineer or manager; not an accountant or a lawyer. If I may take a few minutes of your time, I might be able to present in a brief discussion some interesting facts that will provide the answers to those questions. My discussion will be directed mainly to Federal taxes. However, much of it will be applicable to state and local taxes, also.

Jan 1, 1973

By T. P. Meloy

Understanding the illusive nature of the catastrophic failure of brittle solids is difficult. Proposed is a hypothesis of crack cessation. If, during catastrophic failure, cracks in a brittle solid stop before terminating on a preexisting crack, this hypothesis suggests that the slope of the size distribution curve will be lower. Moreover, this hypothesis suggests that when cracks stop, negative valleys and negative comers appear. Furthermore, particle shapes also change with particle size. While the hypothesis is unverified, it suggests that crack cessation could play a role in the comminution process.

Jan 1, 1996

By N. L. Bingham

The mining industry's image is molded by what the general public knows, or thinks they know about mining. As we prepared for the production of Caterpillar's educational film, Common Ground, we first had to find out exactly what the public perceptions about mining were. Before we could educate people about mining, we had to find out what they already thought. As we broke down those perceptions, we were able to narrow our focus to relevant, realistic approaches for the film. We found out what people didn't know about mining. And most importantly, we singled out the facts they should know... facts that could create more favorable attitudes. This research was instrumental in our final direction for the Common Ground project.

Jan 1, 1994

By William Gleason

"The city of Denver, CO has experienced extreme growth in the past decade, with the population of the city topping more than 700,000 people in 2018. The current storm water drainage system was put in place in the early 1900s and has not been able to keep up with the growth of the city.When it rains north and east of the city, the runoff goes toward the South Platte River. With the dense population and sometimes severe thunderstorms in the summer, the city has experienced significant flooding that not only endangers lives of residents, but some of the storms have caused millions of dollars of property damage.The Platte to Park Hill Project is a $298-million nearterm, four-phase solution to the flooding that includes the Globeville landing outfall; an open drainage project in the Cole neighborhood in north Denver; an area for temporary water detention and another temporary water detention in Park Hill.The largest and most complex phase of the project is the Globeville landing outfall — a $70-million box culvert project that includes a pair of 157-m (515-ft) long, 243-cm (96-in.) diameter storm water tunnels that pass beneath a busy rail yard with 17 tracks for the Union Pacific Railroad (UPRR) and two Regional Transportation District (RTD) commuter rail tracks. The tunnels, which were installed parallel to a pair of existing 243-cm (96-in.) tunnels, were designed by Brierley & Associates as a client of Merrick & Company for the City & County of Denver, and Bradshaw Construction constructed the one-pass tunnels.From the start, it was evident that the tunneling portion of the project would be the most challenging because of the rail yards.“It’s a little bit more complicated because the railroads have such tight restrictions for settlement,” said Rebecca Brock, Brierley’s project manager. “We had a lot of meetings with Union Pacific and RTD to figure out what are prescribed versus tolerable settlements.”“The portion extending beyond the UPRR under the RTD rails was challenging, as RTD is new to tunnel installations under its tracks,” said Lester Bradshaw, president of Bradshaw Construction. “The RTD tracks employed a unique foundation of continuous concrete with integral raised concrete ties on rubber bushings. Minimizing settlement to these tracks was a critical requirement.”"

Jan 9, 2018

By F. B. Henderson, D. Bird, P. L. Hauff, E. C. Prosh

A National Aeronautics and Space Administration (NASA)-funded project (NASA Grant #NAG13-02026) is underway to determine the ability of hyperspectral remote sensing to map mineralogy that affects water quality within a watershed and to identify the relative contributions of natural and anthropogenic sources to that drainage. Natural sources, particularly areas of pyritic hydrothermal alteration, have been found by the Colorado Geological Survey to be a significant source, sometimes the only source, for acidity and/or metals in a number of areas of Colorado (Neubert, 2000). This situation undoubtedly occurs in many places in the Western United States and elsewhere where metallic mineralization occurs. Anthropogenic sources arise from mining and other human activities that increase the exposure of acid-generating materials to weathering processes, thereby increasing acidity and metal loading to drainages where that activity is occurring or has occurred. This project is attempting to determine if these sources can be differentiated through mineralogical analysis, in conjunction with surface water chemistry that controls the precipitated minerals, of the impacted drainages by remote sensing techniques.

Jan 1, 2003

By J. E. Bevan

Once mining compromises the stability of a rock mass, the dangerous task of roof bolting begins. Many attempts have been made to automate this process, but there are still many refinements that need to be made. In the past, roof bolting modules were designed around the abilities of a human operator. Currently, researchers are taking a new approach that focuses on designing modules that can utilize bolting methods that are easily automated. A non-rotating anchor that is locked into position by a linear force (as opposed to a rotational force) was designed by researchers at the U.S. Bureau of Mines. Once the bolt is secured in the bolt-hole by the anchor, the bolt is tensioned and a collet is used to secure the other end of the bolt. This process replaces the traditional bolt-nut fastening method. This program is part of an effort at the U.S. Bureau of Mines to automate the coal mining process.

Jan 1, 1994

By Matthew Burdick, Andrew Rule, Erica Bailey

The Second Narrows Water Supply Tunnel, Burrard Inlet Crossing project for the Greater Vancouver Water District entails deep shaft construction, subway sized pressurized face tunneling through highly variable ground conditions, installation of three permanent steel water mains and construction of elaborate valve chambers adjacent to either shaft. The paper discusses key elements of the planning and implementation of 6.69 m Ø slurry mixshield tunnel boring machine (TBM) assembly in a small diameter deep shaft including incorporation of a fully pressurized launch lock, preparations for saturation diving, surface support infrastructure and initial mining sequence.

Jun 13, 2021

By John W. Harshbarger

The Upper Santa Cruz Groundwater Basin lies in the drainage area of the Santa Cruz River in Arizona, and extends upstream from the community of Rillito to the international boundary, see Figure 1. The principal water use area lies between and includes the cities of Tucson and Nogales. A subsurface geologic barrier near Rillito provides a reasonable dividing line between the groundwaters of the Upper and Lower Santa Cruz Basins. The Upper Basin contains the Tucson and Sahuarita-Continental critical ground- water areas. The Tucson Water Use Area encompasses the Tucson metropolitan area and extends from the northern boundary of the Basin south to the boundary between the Tucson and Sahuarita- Continental critical groundwater areas near San Xavier. The San Xavier Use Area is the San Xavier Indian Reservation. The north and south boundaries of the Continental Use Area coincide with the limits of the Sahuarita-Continental critical groundwater area. The first study of groundwater in this valley was initiated by Dr. G. E. P. Smith in 1905 and the results were published in 1910, followed by a series of bulletins of the Arizona Agricultural Experiment Station, University of Arizona, covering the general field of groundwater development and utilization. Beginning in 1939, the Ground Water Branch of the United States Geologic Survey, in cooperation with the Arizona State Land Department and the Arizona Water Commission (AWC), have published a series of bulletins concerning groundwater occurrence and utilization in various areas of the state. In 1975 and 1977, the AWC published the "Arizona State Water Plan" (1), comprising a detailed inventory of water availability and use in the State of Arizona, and a study of alternative futures.

Jan 1, 1979

By Kevin Schraden, Andrea Pezzi

environmental and social/political changes the world is currently experiencing. Three of major challenges facing the mining industry today are: water scarcity, unpredictable weather conditions that generate a risk of tailings dam failures as well as the correlating social pressure and government regulations that prevent the development of new or expanded tailings dam projects. It is estimated the total number of active, inactive and closed storage facilities globally is over 8,500 containing over 217 km3 of tailings (46% are from copper mining)1 which at some point will need to be addressed. Technologically, there are several solutions for tailings management, including conventional ponds, thickened tails, paste backfill and filtered dry stack tailings. The use of pressure filters, for tailings dewatering is currently being evaluated and often selected as the preferred technology where dry stacking is the chosen solution for residue disposal. This is mainly due to the pressure filters ability and flexibility to address and achieve the current challenging aspects of tailings processing including: • Extremely high capacities of >80,000 dry tons/day • Lower ore grades which require finer grinding and result in a higher amount fine fractions and clay content • Residual moisture targets required for the geotechnical specifications for dry stacking

Feb 1, 2024

By Liuming Wu, Willis Forsling

The complexation of Alizarin Red S (ARS) at the surface of hydrous fluorapatite particles has been investigated at 25.0 C by means of potentiometric titrations, adsorption experiments in 0.1 M NaCI ionic medium, and Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFT) studies. A chemical model describing the reaction at the aqueous mineral surface has been established under equilibrium conditions according to the reaction [== -CaOH2 + HA2 - « _ =PO CaA2 - z + H30&apos;; to (int.) = -5.61 ± 0.02 3 a =PO- logBs-1110(int.) ( ) within the range 8.40 <_ -log[H ] <_ 9.80.] Experimental data were evaluated using the computer program FITEQL on the basis of a constant capacitance model for the electric double layer. The surface complex structure, has been proposed to involve the quinoid and alpha phenolic oxygens of ARS coordinated to the calcium sites on the fluorapatite surface.

Jan 1, 1993

By E. R. Bollinger, N. S. Tanious, R. D. Beckett

The US Bureau of Mines developed hand-made, steel-fiber-reinforced concrete (SFC) blocks for building mine cribs. To ensure wider usage of these cribs, US Steel Mining Co. initiated a joint development and evaluation program with Burrell Construction Co. to mass produce SFC blocks of reasonable dimension, weight, and cost. Small specimens and full-size cribs were evaluated to determine their compressive strength and post failure characteristics. After testing and adjusting of various concrete mixtures, a final formulation was selected that gave a nominal crib strength of 22 MPa (3200 psi) and a nominal modulus of elasticity of 6.9 GPa (1.0 x 106 psi.) These SFC cribs can support 6.4 times as much as a wood crib with the same load-bearing area. The SFC crib was proven to be an economical and effective roof support system through various underground installations.

Jan 1, 1987

By William E. Foreman

The results of the electrokinetic study of the activation of quartz by divalent cations showed that the charge reversal was related to the point at which the cation hydrolyzed. The reversal was not due to the presence of solid hydroxide at the surface of the quartz but due to the charged ions in the solutions. The charge reversal for beryllium at a log molar concentration of 1x10-4 was observed at pH 5 and 9. The quartz was positively charged between a pH reading of 5 to 10. Magnesium at the same log molar concentration did not show a charge reversal from pH 2 to 12. The probable cause of the charge reversal was due to the ionized Be3 (OH)3+3 or Mg (OH)+ . Variations in the electrokinetics of quartz were minimized by heating the sample to 300° C.

Jan 1, 1968

By Christopher Nelsen, Daniel Dobbels, R. Zachary Hollenbeck

Recent major floods have inundated Historic Ellicott City, Maryland, resulting in loss of life and property damage. Howard County, Maryland, has developed the Ellicott City Safe and Sound Plan to mitigate the risk of flash flooding in the Historic District, including a proposed stormwater conveyance tunnel. Challenges to overcome include thick zones of saprolite along the alignment, multiple near-surface structures, and minimal rock cover under an active railroad, while minimizing impacts to the public and historic structures. The project will also pursue recognition through the ISI Envision verification process.

Dec 1, 2022

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 Anthony Harding

In a world of technology and electronic communication, it is easy to forget what engineers do best with a problem: sitting around a table, exchanging views and ideas with sketches and respecting everyone?s view. This was the approach adopted in the project to arrive at a solution for the cross passage opening sup-port for the Seattle University Link Extension. Schedule and space constraints usually impede concurrent cross passage excavation and tunnel boring machine (TBM) operation. And where the space is constrained, opening support solutions that maximize available cross sections are of great benefit. While there are a number of solutions that minimize space, some of these solutions can require expensive steelwork and extensive drilling and fixing. However, following a detailed round-the-table discussion of the options and constraints, it was identified that a shotcrete shell would not only limit obstruction of the space during installation, but also permit easy installation, particularly around services, and avoid costly steelwork and drilling and fixing.

"The use of gas, temperature and airflow sensors to monitor mine ventilation atmospheres offers numerous safety and operational bene-fits to mines. Detection of dangerous gases, changes to airflows and temperature variations are some of the obvious benefits of using at-mospheric sensors in mines. The prediction of atmospheric conditions between sensors however is potentially difficult, and gaining full cover-age a mine will require either many sensors or a method of extrapolat-ing and predicting atmospheric conditions between and downstream from a sparser array of sensors. A dynamic simulation computer model technique is demonstrated to predict time based changes to atmosphere conditions downstream from sensors. The dynamic model predicts the time based changes to conditions throughout a mine model by simulating the mixing, addition and dilution of gases and airflow changes in incremental time steps. The advantages of this method is that a real time overview of full mine atmospheric conditions can be viewed at all locations, even areas without sensors. In addition, with careful planning and consideration of potential contaminant sources, the number of required sensors can be minimized. INTRODUCTIONMine Ventilation Sensors The importance of continuously monitoring mine atmospheres has been recognised since mining underground began and the effects of harmful gases on human health were discovered. Through the 19th and early 20th centuries, coal miners would take canaries underground with them as an early detection system against life threatening gases such as carbon dioxide, carbon monoxide and methane (Figure 1). The canary, normally a very songful bird, would become agitated, stop singing and eventually die if not removed from these gases, signalling the miners to quickly exit the mine (Davalle, 2011)."

Jan 1, 2016

By Hamid Maleki

Rock mechanics models are “data-limited,” i.e., one seldom knows enough about a rock mass to use computational models unambiguously. Statistical methods, however, are capable of being applied where there are good data but a limited understanding of certain natural phenomena, such as the creep of rock salt or elevated risk domains associated with violent failure of strata commonly referred to as coal bumps and coal bursts. Important to these evaluations are (1) having statistically valid data collected consistently and (2) incorporation of analytical calculations for quantifying geologic, mining and particularly geotechnical variables. By combining the strength of the statistical and analytical models, an improved “hybrid” model is created and utilized. To demonstrate the use of hybrid statistical-analytical techniques in rock mechanics problems, three case studies are used. The first case study involves a historic examination of a nuclear waste repository in rock salt, where mathematical models are built using excavation con- vergence data to identify significant variables and estimate future deformation and stability. This case study uses the convergence rate at up to 121 locations of different ages and geometries using monitoring data over the facilities' footprint excavated through 1998. The second case study focuses on ongoing analysis of coal burst mechanics and associated factors. Within the last three decades, a hybrid statistical-analytical methodology has been applied for identifying significant factors affecting coal bursts. This final hybrid model utilizes data from 30 case studies from Utah, Colorado, Kentucky, and other Eastern U.S. mines providing predictive capability for the entire United States coal fields. The last case study is the assessment of Castlegate Sandstone escarpment stability using historic data collected over 17,000-ft of sandstone escarpment exposure in the vicinity of longwall operations in Utah. Results from all three case studies are used for demonstrating the utility of the method in solving ground control problems.

Jun 25, 2024