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By I. Kapageridis

The mining industry worldwide has recognized in the past the need to apply specific rules and guidelines in the reporting of mineral resources and reserves. The high financial investment and risk associated with any mining project and the ever stricter environmental and social controls were the forces behind this recognition. For years the industry experienced the development and enforcement of several codes for reporting accepted by different countries. The implementation of any code can be a confusing task as the guidelines are sometimes general and open to different interpretation. The use of computers in the estimation and reporting of mineral resources and reserves is necessary, particularly when trying to implement particular code guidelines. This paper discusses ways to implement a reporting code in a computerised resource/re-serve estimation study. The implementation is demonstrated using a gold deposit project as an example. The effects of mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors are taken into consideration. This paper also discusses well established reporting codes and the possibility of reaching a single, universally applied code that could be used by Greek mining companies.

Jan 1, 2007

By Christoph Wels, Michael Royle, Shannon Shaw

Intrinsic remediation is the effect of natural attenuation mechanisms - dilution, dispersion, sorption/precipitation and biodegradation - reducing contaminant concentrations in ground water to specified levels at predetermined compliance points in the aquifer. Current monitoring and modeling for post closure was used to assess the current and long-term potential of intrinsic remediation of contaminated seepage originating from a large reactive (sulfidic) tailings impoundment near Questa, New Mexico. It is concluded that the natural attenuation mechanisms of precipitation within the tailings (as a result of buffering) and dilution/dispersion within the aquifer are currently active and likely sufficient to reduce contaminant concentrations to below state standards in the long-term. Other natural attenuation mechanisms such as sorption and biodegradation within the receiving aquife4s) were not assessed here, but are likely further reducing contaminant concentrations. Active interception and recovery of the seepage water is being maintained until monitoring demonstrates that intrinsic remediation has successfully achieved the level of water quality control required.

Jan 1, 2000

By J. J. Gusek

Several final pits in the Seneca No. 1 Surface Coal Mine were abandoned in the 1960's without being reclaimed. In addition, a progressive landslide aggravated by the abandoned mine land conditions was threatening a county road and private property. An AML-funded project to stabilize the landslide and reclaim the final pits was completed in 1986 for the Colorado Division of Mines and Geology (formerly Colorado Mine Land Reclamation Division). The site was visited after ten growing seasons. The land is stable and the vegetation re-establishment is strong. Volunteer native plant species are now invading the reclaimed sites.

Jan 1, 1997

Numerous underground coal mine ventilation seals have been installed in the United States of America prior to 2006 and after implementation of the Mine Improvement and New Emergency Response (MINER) Act. Seal engineering, design, placement, and construction is regulated in industry, but post-construction monitoring of seals is limited to visual inspection of the outby face and seal perimeter, convergence measurement, and atmospheric monitoring. To monitor seal integrity and to provide safe working conditions, a form of non-destructive testing (NDT) is necessary to accurately reflect the health of the seal by detecting post-construction changes, deterioration, or defects within in-situ seals in underground coal mines. Previous research from the National Institute of Safety and Health (NIOSH) has indicated the potential for utilizing ground penetrating radar (GPR) for assessing in-situ mine seals. This paper provides an update to the assessment of proposed NDT methods for seal evaluation using commercially available GPR technologies and systems. Full-scale free-standing seals and large-scale seal specimens were analyzed with an array of GPR units from various manufactures using multiple frequencies.

Feb 23, 2014

By James R. Jones

The concern for air pollution goes back centuries as will be seen from this quotation : "Strife and coal, it seems, have a hand-in-hand historical relationship. It was thought by some . . . in the Middle Ages that burning coal filled the air with dangerous poisons. So great was the concern that in 1306 King Edward I of England passed the first and unquestionably the harshest air pollution legislation edict that history will record. His proclamation declared the use of coal an act punishable by death." As related to coal mining, the air pollution problem is primarily that of its customer when using the fuel. Thus the major impact relates to markets for coal rather than the actual mining operation itself. In the vicinity of the coal mine the problem is principally related to fugitive dust from roads, transfer facilities, loading facilities, crushers, etc., and particulate matter (dust or fly ash) from thermal dryers and air cleaning tables.

Jan 1, 1981

By R. J. Lutton

The suitability of large-stone materials continues to present occasional problems in US construction. Distinctive modes of rock deterioration cracking, spalling, delaminating. disaggregating, disintegrating, and dissolving help to distinguish causes of deterioration. Design requirements, costs, and environmental factors remain critical to performance. The rating of material quality from superior hypes such as granite to marginal types such as conglomerate is too simplistic but may be useful in a preliminary way. Regardless, the market is dominated by limestone/dolomite material types because of their widespread availability. Certain tests that have been standardized are widely accepted and used for evaluating stone as riprap and armor. These tests are adapted from those used extensively for concrete aggregate; they explore the resistance of the rock to destructive processes such as abrasion, freeze-thaw, and wet-dry environmental attack. The field evaluation of the rock source is often as important as testing. Important limitations imposed by natural jointing and variations of bedding are documented in this manner. The field examination also supports the testing by estimating how much of the quarry is rep¬resented by each of the samples to be tested. Finally, quarrying and processing methods and transportation are carefully considered in regard to stone quality, average size, size gradation, and cost.

Jan 1, 1990

By Bryce T. Tripp

Utah's abundant industrial rock-and-mineral resources support a relatively small but important sector of the State's economy. In 1983, six of the top 10 nonfuel mineral commodities (by value) were industrial commodities. Portland cement was ranked fourth, potash fifth, halite sixth, phosphate seventh, construction sand and gravel eighth, and lime tenth. Portland cement was produced by three operators, principally from the Jurassic Twin Creek Limestone. Potash was produced by three companies from Pennsylvanian beds in the Paradox Basin, surface brine of the Great Salt Lake, and subsurface brines of the Great Salt Lake Desert. Halite was produced by eight operators, primarily from surface brine of the Great Salt Lake. Additional production came from salt beds in the Jurassic Arapien Shale, solution mining of the Pennsylvanian Paradox Formation of the Hermosa Group, and subsurface brines of the Paradox Basin. Phosphate was mined by one company from the Permian Meade Peak Phosphatic Shale Member of the Park City Formation. Construction sand and gravel were produced by dozens of operators, primarily from Quaternary Lake Bonneville beach and nearshore deposits. Lime was produced by four operators from Paleozoic formations in the Basin and Range physiographic province of Utah. The future production of these and other industrial commodities, though individually uncertain, is expected to increase gradually as a group. Factors favorable for the future of the industrial commodities industry in Utah include large to almost unlimited resources for the major commodities, a healthy projected population growth, an abundant local supply of relatively inexpensive energy from coal and natural gas, and a favorable corporate tax structure and business climate.

Jan 1, 1987

By C. William Parisi

Since the introduction of mechanical mining, some 35 years ago, a great deal of effort has been expended by the coal industry to solve the coal dust problem. The original concern was the possibility of a dust explosion or the propagation of a gas ignition; however, in recent years it has come to be recognized as a possible 'health hazard as well. In the middle thirties, the Pittsburgh Coal Company began an intensive study of the dust problem to determine the dust levels created by the various cycles of operation in mechanical mining and to make a comparison with those of hand loading operations. Numerous dust samples were collected with a midget impinger and it was found that dust counts varied from 38 to 268 million particles per cubic foot during hand loading and from 96 to 227 million particles per cubic foot during mechanical loading. The study indicated that the source of underground dust in coal mining could be classified as primary or secondary. A primary source is one associated with appreciable degradation of size, that is, where most of the fines capable of becoming air-borne are produced. A secondary source is one in which most of the fines have been produced at some previous operation and are in such condition that they can become air-borne. Cutting, drilling and blasting are the operations which produce the primary dust. Secondary dust is formed by operations which include; loading, transportation and discharge at transfer points. The study showed clearly that the coal cutting operation was responsible for the greatest amount of dust and that the amount of dust produced varied directly with the speed of cutting; type and dullness of cutting bits; and the distance the cuttings had to fall to the floor. The information obtained from the study enabled our company to decide on a course of action and the direction to follow. With the cooperation of mining machine manufacturers, water tanks with a 200 gallon capacity were built into the machine trucks and were provided with a pump driven by a small motor. A length of 1/2" water hose carried the water from the pump to the two water spray nozzles located at the front of the machine. Water was delivered to the machine tanks by water cars which were filled on the surface or from an underground water supply. It was during these early days that wetting agents were introduced into the water system. Our studies revealed that wetting agents did little better than plain water in the abatement of the dust problem. It was found that when using a wetting agent less water was required to obtain the same results but we could not take advantage of this fact because it was almost impossible to keep the smaller nozzles open to reduce the amount of water being used.

Jan 1, 1967

The stability of mine roofs in permafrost zones is determined mainly by temperature and ice content. The deformation resulting from creep and temperature-dependent physical properties of frozen rock mass is the dominant component of total deformation. Roof bolts can consolidate the roof and control its deformation. In this paper, a finite-element model, for the analysis of the effects of roof bolting in a frozen rock mass is presented. The model includes the variables normally encountered when analyzing the effects of roof bolting in rocks. It also accounts for properties unique to frozen rock mass: creep deformation and the change in Young's modulus with changing temperature. The model shows that, as bolt spacing decreases, there is a trade-off between increased roof stability from increased mechanical support and decreased stability from increased conduction of heat into the frozen roof. This result was expected and shows that, for a given set of rock-mass conditions, including ice content, temperature, particle size, etc., there is an optimum bolt length and bolt density for minimum roof deflection.

Jan 1, 1997

The trend in the U.S. coal industry in recent years has been a continuous increase in the percentage of coal produced by surface mining methods. Though the predicted energy demands promise a good market for coal, growing legal and environmental issues make the exploitation of a coal deposit by surface methods a difficult and challenging task. Major emphasis has to be placed on the development of integrated mining and reclamation schemes which enhance the possibilities of post mining land uses. Since no major breakthroughs are foreseen in the near future in surface mining equipment, innovative applications of current equipment must be developed. Draglines have been and are expected to continue as the primary earthmovers in surface mining of coal. A dragline simulation model has been developed which has the capability to analyze various deployment schemes such as conventional side casting, advance benching, and extended benching. The mathematical aspects of the model, the input data, and the output results are discussed with reference to an application in an operating mine. The model can be used to select a suitable dragline for given geological and mining conditions and to study the effect of alternative mining layouts and spoiling plans on machine production.

Jan 1, 1979

By Richard C. Fountain

The Central Florida Phosphate District is located in southwestern Polk, southeastern Hillsborough, Manatee, and Hardee Counties, Florida, flanking the.southern end of a major structural uplift known a the Ocala arch. Ore control problems here are varied and unique due to non-homogeneity of matrix and high volume mining operations. Overburden stripping and matrix mining are performed by large draglines, the matrix being slurrified and transported to the processing plants hydraulically. Production geologists' responsibilities include, 1) prediction of special mining problems, 2) prediction of ore quality and quantity, and 3) the physical control of the ore quality and recovery during mining. prediction is based on core drilling and visual inspection and analysis of the core samples. Basic economic, and physical minability criteria are thus established. Ore grade and tonnage recovery are of particular importance with emphasis being placed on coordination between mining and processing personnel. Routine inspection of the working pit face is of prime importance and both physical and quality variations are pointed out to the mining supervision. Physical problems in ore control occur due to erratic clay, dolomitic limestone and sand lenses. Near surface ground water is abundant, posing a threat to recovery. Contaminants of the phosphate ore are large quartz grains, pebbles of cemented quartz sand, clay balls, iron oxide laminac and dolomitic limestone particles. Success of the ore control program is predicated on a balance between predicted ore tonnages and grade and actual production. The geologists' primary attention is directed toward this balance.

Jan 1, 1972

By J de Cuyper, G. Rinelli, A. M. Marabini, V. Alesse, W. Freyberger

Salicylaldehyde, a chelating agent for tin, has been found to function as a collector for the flotation of cassiterite. Infrared and nuclear magnetic resonance studies clearly show that salicylaldehyde can form a chelate compound in bulk and at the surface. Results are also given for the flotation of a tin ore with this reagent.

Jan 1, 1976

By R. Owens, C. Roos, B. Hill, S. Rosenthal

It is common practice, and even legally required in many jurisdictions, to design two-lane haul roads in open pit mines to three and a half times the widest dimension of the haul trucks operating on the road. In open pit gold mines with high strip ratios, the road width has a significant impact on the economics of a design. It is possible to minimize the flattening of the highwall if the road width is reduced, assuming the width used is not needed to flatten the slopes for geotechnical purposes. With the use of autonomous haulage and pullouts, it may be possible to operate safely and efficiently on a reduced road width of two times the width of the hauling equipment.

Mar 2, 2022

By Raymond S. Shrode

Transportation is one of several important increments in the total market cost of most commodities. On a national average it has been reported that transportation accounts for about 25% of the total cost of a product at the market place. And industrial minerals are no exception. In fact, the proportionate cost frequently exceeds the 25% average. Further, it may actually determine the economic value of a deposit. Transportation may possibly be thought of as a specialized subject of concern only to a traffic manager and of only nominal interest to the mining engineer, the geologist or other technically oriented member of mineral producers' staff. However, in the industrial minerals field, interest is not commonly confined to exploration, development, production or marketing, but is in contrast an overlapping one. In a very real sense this broad area of interest in the total economics of the business is the specialty of the industrial minerals man. And transportation is a vital part of the total picture. Comments in this paper deal with rail transportation.

Jan 1, 1969

By Jr. Pitts

Elevation of surface charge density on colloidal particles in the presence of a high potential electrostatic field is demonstrated as a viable technique for preventing the accumulation of solids in solvent extraction circuits. The effect of the technique is manifest by relative turbidity measurements between pregnant leach solution and raffinate, by changes in the character of the sludge accumulations, by alteration of the zeta potential of particulates, and by a general reduction in the mass of solids.

Jan 1, 1992

By D. A. Saint Don, M. Prueher, S. Barnwell

With the current changes in technology, multiple methods are now available for aggregate resource identification. From Sonic to Coring, Reverse Circulation to Percussive, there are many choices to make regarding drilling technology. The discussion will outline the methods above with focus on aggregate investigation and highlight the new technologies that will make a difference in your search.

Jan 1, 2004

By Randhir S. Sehgal

After some decades of lying low and being treated as a second rate fuel, coal is back in the news. Production is rising. Predictions are for an ever expanding use, and they differ only in their rates of increase. Even the FBI is involved in trying to stop fraudulent sales of non-existent coal lands and leases to the innocent. In short, we have a nearly chaotic boom on our hands. Obviously our energy production base is in the process of undergoing a major shift, and the process will present many problems. However, there is little doubt that the industry has the basic strength and organization to be able to deal with the new issues that will arise as a result of these shifts in production and use of coal. After all, it does produce nearly 800 M tpy now, and coal is the single biggest fuel for generation of electricity. This role of coal is illustrated in the table below, which shows the coal equivalent quantities of various fuels used in the production of electricity.

Jan 1, 1980

By J. M. Kruger, P. Berendsen, A. Martinez

High-resolution ground-penetrating radar (GPR) was used to image the near-surface extent of two exposed Late Cretaceous kimberlites intruded into lower Permian limestone and dolomite host rocks in northeast Kansas. Six parallel GPR profiles identify the margin of the Randolph 1 kimberlite by the up-bending and termination of limestone reflectors. Five radially intersecting GPR profiles identify the elliptical margin of the Randolph 2 kimberlite by the termination of dolomite reflectors near or below the kimberlite's mushroom shaped cap. These results suggest GPR may augment magnetic methods for the delineation of kimberlites or other forceful intrusions in a layered host rock where thick, conductive soil or shale is not present at the surface.

Jan 1, 1998

By C. Zhou, B. Whisner, J. Carr

Proximity Detection Systems (PDSs) are used in the mining industry for protecting mine workers from striking, pinning, and crushing injuries when they work in close proximity to heavy machines such as continuous mining machines (CMMs). Currently all Mine Safety and Health Administration (MSHA) approved PDSs are magnetic field based systems which can be influenced by the presence of wire mesh that is commonly used for supporting roof and ribs in underground coal m ines. In this paper, researchers at the National Institute for Occupational Safety and Health (NIOSH) characterize the influence of the mesh on the performance of magnetic PDSs by measuring the magnetic field difference around a CMM caused by the presence of the mesh. The results show that the magnetic fields are generally enhanced by the mesh which causes the PDS detection zones to be increased correspondingly. It was discovered that the fields around the joints of two mesh sections have the greatest enhancement and thus deserve more attention. In addition, it is found that the presence of mesh can also cause a variation in the generator current. The influence of mesh is characterized by the change in the generator current with respect to the distance between the generator and the mesh. It was found that the generator current change caused by the mesh can be significant (on the order of ten) when the mesh is extremely close to the generator (e.g, less than 1 cm) and is negligible when mesh is relatively far (greater than 0.15 m). The findings in this paper can be used to develop guidelines and best practices to mitigate the influence of mesh on PDSs. INTRODUCTION The Mine Safety and Health Administration (MSHA) requires operators of underground coal mines to equip place-changing continuous mining machines (CMMs) with proximity detection systems (PDSs) to protect mine workers from striking, pinning and crushing injuries when they work around these heavy machines. Although a variety of technologies can be implemented for proximity detection, the magnetic-field-based PDS that was originally developed at the National Institute for Occupational Safety and Health (NIOSH) has shown great effectiveness in challenging mining environments and currently all MSHA-approved PDSs are magnetic-field-based systems. As shown in Figure 1, a magnetic PDS typically includes two major components----the magnetic field generator and the Miner Wearable Component (MWC). Magnetic fields are generated by injecting a high electric current into a ferrite-rod antenna sealed in the generator. The magnetic field strength detected by an MWC varies with the distance between the MWC and the generator. In a typical PDS, multiple generators are mounted on different locations of the machine. The relative location/zone of an MWC is determined based on the field strengths from different generators picked by the MWC. Ideally, for a PDS to work properly in the underground, the magnetic fields generated by the different generators should be stable and not vary with the environment, as the system would interpret any variation of the magnetic field as a result of the distance change between the machine and the miner wearing the MWC. In reality, however, this is not always the case since magnetic fields can be altered by a number of environmental factors such as the presence of steel wire mesh that has been widely used in underground coal mines for supporting roof and ribs In this paper, the influence of mesh on the PDS performance is investigated and the magnetic field change caused by the mesh is measured.

Jan 1, 2019

By George A. Takach

The U.S. Bureau of Mines is conducting research with the goal of automating underground coal mine roof bolters for greater mine safety. In the project described here, the Bureau has focused on automating the drilling portion of the drilling and bolting cycle. A drill monitoring system designed and developed by Parvus Corp. of Salt Lake City. UT, was placed on a Bureau model roof- bolting drill. The drilling parameters of torque, thrust, rotation rate, penetration rate, and position are monitored through sensors connected to an asynchronous, control-oriented local area network (LAN) that communicates with data-accumulating and data-processing nodes. By placing microprocessors at the two data nodes and at the valve control nodes, and combining these nodes with a personal computer (PC), the monitoring and control system can achieve parallel processing capabilities. Such capabilities are referred to as locally intelligent distributed processing. Only data that have changed significantly are reported through the LAN to a supervisory control and data acquisition (SCADA) system mounted on an IBM- compatible 80286 PC. The SCADA system displays the values of the drilling parameters and calculates the specific energy of drilling, which is then used as an indicator of the type of rock being drilled. Besides monitoring the drilling process, an operator at the computer can control the rotation and thrust of the drill from a remote location through the SCADA program and can set drilling parameters on the basis of observed values of the specific energy of drilling.

Jan 1, 1992