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By Robert M. Rowe

Among the increasing operating costs affecting today' s processing facilities are those necessary in meeting the continually growing requirement for safe and environmentally sound materials- control and handling procedures. Of particular interest are materials listed as hazardous, the need to maintain accurate records of their acquisition, consumption and disposal, and the obligation to employees and the community to have information available regarding such materials. Some requirements affecting modern operating facilities are reviewed in this paper, and potential methods for dealing with complex handling and documentation requirements, including computer automation, are discussed.

Jan 1, 1991

By M. Karmis

Surface subsidence has been recognized as an inevitable consequence of underground coal mining for several centuries. The damage resulting from this phenomenon has been witnessed in rural as well as in urban areas and ranges from simple land settlement to severe structural damage to buildings. Subsidence prevention is not feasible, at least under the existing technological and economic constraints of underground coal mining. Using a rational method of subsidence prediction, it has been demonstrated in many coalfields that subsidence control can be successfully practiced in order to reduce and accommodate subsidence within environmentally acceptable levels. This paper presents the development and testing of a subsidence model, based on the zone area method. This technique is a refined development of the influence functions and it is capable of investigating a mining plan of any shape, thus facilitating both longwall and room-and-pillar mining systems. More specifically, this study can be divided into two major efforts: (a) The development of the zone area model. This formulation was designed to accommodate the analysis of an optimum number of zones, over the area of interest, both accurately and efficiently. (b) The testing of the computer techniques with appropriate field measurements. In order to accomplish this, published as well as unpublished information was collected and analyzed according to a regionalized scheme. This procedure minimized differences in subsidence characteristics between the various coalfields and allowed a regional validation of the predictive capabilities of the model.

Jan 1, 1982

By C. J. Savage

Rio Tinto Minera, S.A. operates in Southern Spain, at one of the most ancient mining sites in the world, using advanced computerised mine planning. This paper describes the development and application of the mine planning systems to the copper and gold/silver operations. It briefly covers the hardware configuration, and the advantages and improvements in mine planning achieved. The system's application started with the long term mine planning of Cerro Colorado (open pit) copper mine and was gradually extended to cater for the medium and short term planning requirements of the other operations of the Company. The base of the system is a mineral inventory established by the combined use of the geology and geostatistical methods, and compatible with the mine planning requirements. The planning system has three major components: one used for open pit design and long term mine planning, another used for blast evaluation and finally one used for short term mine planning. Recently, a fourth component has been added to the system for reconciliation between predicted and actual tonnages and grades. There is common data file transfer throughout the system.

Jan 1, 1986

By John J. Reed

The 1945 fire at the Braden (El Teniente) Copper Mine in Chile took 354 lives, and ranks as the most lethal metal mine fire in history. The mine was developed in the wall of a canyon over 900 m (3,000 ft) deep. Principal entrance was through a main haulage adit at the canyon bottom, and up through two internal shafts. Mining was by block caving from the top of the orebody with most of about 900 men on shift working in three production areas. Ore was transferred by gravity to the haulage level through a complex system of ore passes with associated ladderways. Normal mine ventilation was incast through numerous level portals and up- cast through the shafts and raises. The fire was confined to a maintenance shop just inside the portal of the lower production level. Smoke, gases and flammable vapors were drawn into the mine, and a subsequent explosion of the gases destroyed an air door and injected carbon monoxide into the workings. Falling water in a drainage raise near the fire made it downcast, which carried gases down to all the lower levels where they were drawn into the levels and then up connecting raises. Miners attempting to escape by climbing down the ladderways from the production levels were met and killed by the rising gases.

Jan 1, 1989

By A. E. Hall, D. M. Mchaina

This paper outlines a proposed research project to investigate secondary sulphide ignitions. Sulphide dust explosions have resulted in loss of production and considerable capital and equipment replacement cost in Canadian mines. The practical application of laboratory test results to actual mine situations presents a complex problem and is a field requiring immediate investigation. The factors contributing to the outbreak of sulphide ignitions are not clearly understood. This indicates a need for future research to study the influence of blasting parameters, exhaust temperatures, and dust characteristics on secondary ignitions at source. The aim is to establish realistic quantities for each of the parameters and develop a model that will incorporate field and laboratory quantities. It may be possible to predict outcomes of sulphide ignitions when the parameters are known. It is also planned to study the techno-economic feasibility of the preventive and control methods. One aspect of planned future research requires quantification of some terms by obtaining measurements of pollutant concentrations and size distribution of the airborne dust in an underground environment immediately after a main blast. A blast-proof aerosol sampling package to measure the source term will be designed. This sampling package will consist of a sampling section and a shield which will be capable of withstanding a blast explosion. The accuracy in measuring the variables and combination of variables will be the main focus in this proposed study.

Jan 1, 1987

By J. C. Yingling, J. Sottile

This paper addresses detailed models of the temporal pattern of material flows produced by longwall mining units and procedures for inferring the parameters of these models from field data. First, a model is established that predicts material flows referred to shearer position and cutting element. This model is comprised of trend and fluctuation components. The trend component, which is invariant between repetitions of the cut cycle, accounts for deterministic effects on the flow pattern, such as web depth variation as a function of the cutting operation, systematic tendencies for seam height and cutting speed variations along the face, changes in the relative velocity between the shearer and face conveyor, etc. The fluctuation component models random effects on material flow and employs time series approaches. Subsequently, a method is given for converting the positionally-referenced flows to temporally-referenced flows. The model serves as a basis for generating detailed, accurate computer simulations of material flows from longwall units. As such, it provides a more rigorous foundation for analysis of cutting procedures and outby materials handling systems in longwall mines.

Jan 1, 1994

By F. F. Aplan, S. Chander, A. R. Alaboyun

Several aspects of the capture of hydrophobic dust particles by droplets in sprays have been studied. The particle capture depends on several sub-processes involving collision, adhesion and engulfment. The collision events between dust particles and a single droplet were observed with a high speed motion analysis system to determine the influence of a surfactant on the capture process. In the adhesive process it was observed that the dust particles are collected at the surface of the water droplet to produce a rigid film at high dust loadings. In the presence of the surfactant, however, the particles were engulfed inside the droplet keeping a fresh surface on the droplet available for capture of more particles. A theoretical analysis is presented to take into account the role of contact angle on the penetration of particles into droplets. A significant increase in collection efficiency was observed with decrease in droplet size.

Jan 1, 1991

By Howard L. Hartman

To concede that I am the most surprised - not to mention the least likely - recipient of the Daniel C. Jackling Award is a true confession I must share with you. Quite honestly, I've asked myself, "Why me?" The Jackling Award has a well-deserved reputation of being a practitioner's, a doer's, a CEO's award - not kudos for a retired school teacher! While at least five of the previous recipients have taught in universities, to my knowledge I am the first to earn the award for "alleged" academic accomplishments. It is humbling enough to keep me livable for a long time. If you glance over the roster of Jackling Award lecture topics, you will spot another anomaly: The lectures last year and this deal with the subject of education - the only two in the 37-year history of the award. The two complement one another rather well, too, C. Allen Bom of Amax addressing critical needs of public education, while I am going to look at the post-high-school years. But I want to focus on more than engineering education. The training role of industry - the principal consumer of our product-also warrants examination. As I hope to establish, there is something unique about mining engineering - education and practice - that is both strength and weakness. We need to recognize that, if we are to cope with the weaknesses in order to capitalize on the strengths. We look at five premises that relate to the uniqueness of the mining engineer and his or her preparation for a professional career.

Jan 1, 1991

By Giovanni Toniatti

Brazil is a country with continental dimensions. It hosts many different varieties of terranes and geological environments in its 8.5 million km2 (3.28 million sq miles). This mineral endowment has been important for the country's economic and social development process since the early colonial period, leaving Brazil with a legacy of almost 400 years of mining tradition. Mining in Brazil started in the early 17th century with diamond and gold discoveries. The made the country the leading producer of both for more than a century. This phase faded by the late 18th century when the alluvial deposits were depleted. It finally yielded to competing countries where technology and capital were being applied more efficiently. This period of mining dormancy lasted from the late 19th century until the first decades of the 20th century when Brazilian mining picked up. There was growing pressure on mineral resources by the affluence of the industrial society. The fast-growing demand resulting from the two world wars had brought the Brazilian mineral wealth back to the scene. This second Brazilian mineral boom made the country a leading producer of iron and manganese ore, quartz crystals and other strategic minerals. This expansion in Brazil's mining industry provided the basis for the country's industrialization process. This was led by the Brazilian steel and petroleum industries. Unfortunately, the thrust provided by this modern industrial basis was not properly used as a lever for further industrial development. The upstream industrialization process was not supported by the proper development of the raw materials supplying basis. The resulting industrial model was heavily dependent on imports of raw materials. It did not support the economic growth and faced fierce industrial competitiveness and sophistication that emerged with the postwar economic boom.

Jan 1, 1997

By B. C. B. Pretorius

A heat load analysis of the very hot sub-shaft area of Loraine gold mine situated near Welkom, South Africa, showed. that the heat that needed to be removed to give acceptable wet-bulb temperatures at the working faces could not be done by the normal ventilation air alone, but would have to be complemented with extensive refrigeration. The paper outlines the considerations in selecting the cooling system adopted for this shaft.

Jan 1, 1980

By F. Seymour

A modified three-dimensional Lerches-Grossmann (LG) graph tree algorithm that generates the complete set of nested maximum valued pits in a single run is presented. This modified LG algorithm looks at the relative strength (average value) of the branches (groups of blocks). Pointers are allocated and pruned until there are no members of weaker (lower average value) branches overlying members of stronger (higher average value) branches. The final set of strong branches arc listed in order of decreasing strength. The pits they represent form the maximum valued convex hull for a single-variable pit-limit parameterization. A description of the algorithm is given along with examples of lion it has been applied at Newmont.

Jan 1, 1996

By R. R. Klimpel

During the period of 1973-79, an extensive period of research and development was undertaken by Klimpel and coworkers (1980, 1981, 1982a, 1982b, 1983. 1984, 1987) on the identification of a commercially viable chemically assisted approach to improving the efficiency of the wet grinding of coals and ores in tumbling media mills. The emphasis of the previous publications just listed was on the engineering use implications of controlling-slurry viscosity (rheology) in laboratory and plant scale grinding devices. In this paper, some discussion and results pertaining to the actual chemical screening phase will be presented.

Jan 1, 1988

By R. J. Barnes

Consider a typical blast at a surface gold mine in North America. For example, the low-grade area of Bench 4000 at AMAX Gold's Sleeper Mine (Winnemucca, Nevada). Bench 4000 is 20 feet high (=6m) , and blast holes are drilled and sampled on a 14 foot by 14 foot square grid (a4m x 4m). A representative blast includes between 50 and 150 holes, encompassing 15,000 to 45,000 tons of material (w14,000 to 41,000 metric tons).

Jan 1, 1989

By H. E. Bonner

The recovery of fine coal has historically had limited success due to the intimate clay association on the surfaces of the coal particles. This clay presence has detrimentally affected conventional beneficiation techniques resulting in a recovered product containing unacceptably high concentrations of ash and moisture. An ultrasonically activated tray that operates in a continuous fashion has been developed that separates the clay film from each particle's surfaces. This separation is of sufficient duration to allow conventional beneficiation techniques to be utilized more efficiently.

Jan 1, 1989

By E. Koufetzis

Rock mass classification systems are core elements of tunneling and empirical mine design worldwide. The Bauxite division of S&B Industrial Minerals S.A. decided to implement a rock mass classification system in order to provide mining engineers and supervisors of the underground mines, with guidelines of stability performance and with a complementary tool for the selection of the appropriate tunnel support. The back analysis system employed is based on visual observation of especially selected underground mine sites, representative of all rock types. This fact combined with the failure or success of the already existing support system, constitute the fundamental part of the work undertaken. The paper is divided into three main parts. In the first part the classification methods of Q, RMR89 and GSI are presented and the advantages and disadvantages of each method in connection with underground mining are indicated. RMR89 and GSI are conclusively selected for use, the main criteria for the selection being, the simplicity in use and the competency of the support system suggested for each rock mass category. The second part points out the methodology for measurements, the practical difficulties encountered during this process and the guiding principles followed, in order to avoid these problems. In the third part, the final conclusion of this project is demonstrated and the different rock mass categories are presented with their relative support recommendations, as they were applied and tested in all phases of the bauxite mines? exploitation. The generated methodology is being implemented by the site mining engineers, for validation and potential improvement.

Jan 1, 2008

By Ing. E. h. Martin Herrenknecht

The paper will describe a number of developments and innovations now in use in microtunnelling machines. These include the use of fuzzy logic steering systems, the proven ability to successfully undertake complex curved microtunnel drives, the ability to complete ultra long drives using microtunnelling techniques, and machines with access to the face of the machine from inside the machine. The ability to tunnel in relatively hard rock utilizing a rock head with back loaded cutters changeable from inside the microtunnel machine and the ability to utilize microtunnel machines in multi modes, such as hard rock mode, “open” mode, EPB mode, and slurry mode with the same base machine again with access to the face of the machine will be described. In addition, the latest computer technology gives the operator “full visualization” of machine functions together with the ability to data log machine operating parameters. Reference will be made to a number of projects worldwide recently completed or under way where these innovations have successfully been utilized.

Jan 1, 1999

By R. C. Kirkman

Your interesting and well-written paper brings up the issue of the purpose or use of a mineral property appraisal, specifically the value of these evaluations when the quality and quantity of the mineral resource to be exploited have not been thoroughly investigated. I am not a practicing professional in regards to valuation of limestone investment opportunities. I simply wish to make a few generic observations about the appraisal process in order to stimulate meaningful thinking by appraisal professionals whose reports may be reviewed by professional investors and "laypersons" alike. It is my contention that the analysis given in your paper is very thorough, considering the data that was made available to you. But I would not like to be the person responsible for investment decision making without having a feel for the risk involved. Therefore, the reviewer must classify this type of analysis as relatively "subjective" because they have not received an indication of the inherent risk involved in exploiting a mineral resource. This risk can best be quantified by using probabilistic methods in conjunction with the quality and quantity of the mineral to be produced. Most appraisals passively ignore this problem. Specifically, you have accurately identified the various costs and values entering the economic appraisal process. These can usually be quantified with a great deal more certainty than the capability of the resource to provide 25 years of quality material. Also, in Cases A (West Virginia)and B (Alabama), you are fortunate enough to have previous operations data. What if there had never been production from these properties? How does a potential mineral property investor evaluate the resource capability to meet various projected financial outcomes without spending a good deal of up-front capital to drill and delineate enough quality resources for a 20-plus year operation. These questions pose a substantial risk to any potential mineral investor. Only probabilistic methods should be used to quantify this type of problem, short of drilling and metallurgical testing. I might be considered a "layperson," not being familiar

Jan 1, 1991

By Randal J. Barnes

There are many methods available for the estimation of geologic parameters (Popoff, 1966; Barnes, 1980). In the last decade a new and relatively sophisticated technique using statistical theory has emerged: geostatistical kriging (David, 1977; Journal and Huijbregts, 1978; Rendu, 1978). An interesting property of geostatistical estimation is that when a geologic parameter is estimated for a given volume, not only is the estimate generated but an associated measure of certainty is produced as well. This statistical measure of estimation confidence is called the estimation variance. While the concept of an estimation variance is universally considered to be a good idea, mining engineers and geologists do not currently have the tools to incorporate it into their planning and quantitative analysis. This paper attempts to develop and present some of the necessary tools required to incorporate estimation uncertainty into mine planning. Geologic uncertainty is portrayed as an economic business risk. This risk is objectively characterized, and-the associated cost is quantified. Geologic delineation sampling is viewed in this light as an economic commodity with an associated cost and value. A coal mine planning example is used as a focus in this presentation. The data used is real, though it has been modified to maintain data security and project anonymity.

Jan 1, 1986

By M. Canty

This paper presents results from pilot-scale and field testing of an innovative technology that uses sulfate-reducing bacteria (SRB) to treat and control acid mine drainage (AMD). Sulfate-reducing bacteria, a common group of anaerobic bacteria, produce hydrogen sulfide and bicarbonate when supplied with sources of carbon and sulfate. Hydrogen sulfide reacts with metal ions in AMD, precipitating them as metal sulfides. The bicarbonate produced serves to help neutralize the drainage. Pilot-scale metal-removal efficiencies reached 99% for zinc, 99% for aluminum, 96% for manganese, 98% for cadmium and 96% for copper. However, the iron and arsenic removals were not as effective as the aforementioned metals. This was largely attributed to high levels of iron and arsenic that contaminating the organic substrate. There was evidence that both adsorption and sulfate reduction were occurring within the reactors. The SRB field demonstration involved using the flooded subsurface mine workings of the Lilly/Orphan Boy Mine near Elliston, MT, as an "in situ biological reactor." In the mine, high removal efficiencies were observed for aluminum, cadmium, copper and zinc (70% to near 100%) during the four years of monitoring. However, for reasons similar to the pilot scale testing, low removal efficiencies were observed for arsenic and iron. Sulfate reduction was evident by measured decreases in sulfate and the detection of soluble sulfide within the mine water.

Jan 1, 2000

By S. K. Mishra, S. B. Kanungo, D. Biswal

Jigging of the -2.8 +0.7-mm size fraction of a friable, low-grade manganese ore sample from Andhra Pradesh increased the Mn content of a concentrate by 7% to 8%, with an average recovery of 57%. The jig concentrate was mixed with the unjigged -0.7-mm size fraction and ground to -150 µm. The sample was then subjected to wet high-intensity magnetic separation (WHIMS). The magnetic fraction thus obtained showed an increase in Mn content of 6%, but with an overall recovery of only 50%. The results of hydrocyclone classification of -150- µm ground ore indicated that the method is not capable of upgrading the manganese content, as both ferromanganese oxides and aluminosilicate gangue minerals constitute the fine size fraction. However, when the nonmagnetic fraction obtained from the WHIMS of -150- µm ore is subjected to hydrocyclone classification and the underflow obtained is subjected to WHIMS again, an overall recovery of about 50% to 52% is obtained with at least a 7% to 8% increase in the Mn content of the product. The phosphorus content in the product is not reduced by either of the two combinations of methods. The complex association of phosphorus with all the major phases in the ore has been clearly demonstrated from the linear correlation between the distribution ratios of major constituent phases and phosphorus.

Jan 1, 2000