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By Dave D. Ferris

Today the coal industry is beginning to use some very fundamental economic evaluations to determine the most economical circuit to produce a specified saleable product. The fundamental economic methods used are standard return on investment and net present value calculations. By utilizing these economical evaluations, one can justify a larger capital expenditure and realize more return for an investment over the life of a coal property.

Jan 1, 1983

By Alan A. Campoli, Michael D. Zuber, Frank E. McCall, Gerald L. Finfinger

Injecting water under pressure to wet the coalbed in advance of mining reduces mining-generated respirable dust. Owing to economic and geological barriers, water infusion for longwall dust control in the United States is currently limited to the Pocahontas No. 3 Coalbed in Virginia. Water is pumped into the coalbed through underground boreholes drilled horizontally from the headgate toward the tailgate side of retreat longwall panels. This paper theorizes that the barriers to widespread utilization of water infusion for longwall dust control could be overcome by long-duration, low-pressure water infusion through vertical gob gas boreholes. Currently, 43% of the 72 longwall mines in the United States employ vertical gob gas boreholes. Computer coalbed reservoir simulation suggests that one vertical surface borehole could infuse the same longwall panel area as four horizontal boreholes in the current water infusion system for longwall dust control in the Pocahontas No. 3 Coalbed.

Jan 1, 1995

By G. Pan

A geostatistical approach is proposed for the design of infill drilling programs. The method consists of the following four major steps: developing geological favorability models, delineating mineralization and ore envelopes, classifying resource potentials, and designing infill drilling patterns. Geological modeling develops the permissible geological zones in which infill drilling is designed. Modeling mineralization and ore envelopes establishes criteria on the potential blocks to be drilled. The blocks that are included within the ore envelopes are considered in the infill drilling. The following four types of resource potentials are used in this analysis: measured, indicated, possible and barren. Blocks in the indicated category are the top targets to be confirmed in infill drilling. Blocks of possible resources may be considered exploration targets. The algorithms involved in the analysis include indicator favorability analysis, indicator kriging and ordinary kriging. A case study on a gold deposit of the Carlin type is presented to demonstrate the methodology. The deposit was originally delineated by a sparse drilling program with about 230ft of average spacing. The infill drilling design, based on the new method, suggests a significant reduction on the number of holes from a regular-grid infill drilling pattern.

Jan 1, 1996

By Maurice Jackson et a1

Golder Moffitt and Associates (GMA)", were commissioned to reassess a large metallic low grade orebody. One of the aims of the study was to estimate recoverable reserves. Recoverable reserves are here defined as ore reserves for a specific mining block size. The mining block is that block on which the decision that the material is ore or waste is made. Recoverable reserves take into consideration mining methods. New methods for solving this type of problem were recently developed in Geostatistics and so for this reason GMA called for the technical assistance of the Centre de Geostatistique (C.G). The complete estimation was done using the geostatistical techniques and programs of the C.G together with some of the programs of GMA. As the mine was in production at the time the study commenced it was-possible to make frequent checks on the estimated values using blast-hole data. The ore reserves were also estimated using the more conventional interpolation method of inverse square of distance weighting.

Jan 1, 1979

By K. Brady

Making progress on sustainable development will require greater attention to the management of materials produced from mine exploration through use to reuse, recovery and recycling. Material stewardship is a concept that embodies the range of activities required for optimal and appropriate use of minerals and metals in society. The following paper provides an overview of some recent initiatives that promote the stewardship of minerals and metals in society. The initiatives described are being conducted by organisations ? the International Zinc Association, the Canadian Copper & Brass Development Association and the International Council on Mining & Metals. These associations illustrate stewardship activities at three different levels: - an international association representing companies that produce a range of minerals and metals; - an international commodity association; and - a regional association. For each initiative, information is presented on its development, scope and outlook. This paper draws heavily from work of the associations but the viewpoints are the responsibility of the authors.

Jan 1, 2007

By M. K. LeBegue

Water sprays located behind the bits of cutter drums have been shown to reduce the incidence of face ignitions. This paper details the design approach to successfully incorporating water seals into a drum miner cutter head.

Jan 1, 1999

Editor’s note: As usual, the June issue features an industrial minerals review. And some thanks are in order. Thank you to the industrial minerals annual-review editor, to the technical committees chair and vice chairs and to the authors of the individual commodity profiles. Jim Norman of GeoTrans Inc. is the industrial minerals annual-review editor. William Langer, U.S. Geological Survey, is the chair of the SME industrial minerals technical committees and the vice chair of the technical committee for construction materials. Other technical committee vice chairs include: •Lucy McCartan, U.S. Geological Survey, agricultural minerals. •Steve Herron, Oglebay Norton Performance Minerals, ceramics and refractory materials. •Srinivas Veeramasuneni, U.S. Gypsum, chemical raw materials. •Ismail Yildirim, Imerys, fillers and pigments. •Charles Landis, BPM Minerals, sorbents, filters and process aids. •Ray Harris, Wyoming Geological Survey, specialty minerals. Their help makes possible this June industrial minerals issue. On behalf of the readers, the editors thank them

Jan 1, 2004

By K. Whysner

The recycling of metal resources in mining influenced water (MIW) requires a paradigm shift from within the mine water treatment industry. The potential to recover zinc for beneficial use in the micronutrient fertilizer industry was investigated through a survey of zinc micronutrient fertilizer representatives. An application of the findings to a case study of the Argo Tunnel influent MIW was then implemented. It was concluded that the potential to beneficially reuse MIW residuals in fertilizers exists; the current process sequences of treatment will need to be modified if metal recycling is to be prioritized.

Feb 27, 2013

By Christian F. Baiz

Industrial minerals can have similar financing requirements to those needs of metaliferrous and coal mining projects. Although, one may see many similarities in the fundamentals of the various risks that must be evaluated in lending to any specific project, one of the outstanding differences is the understanding of the many different markets that these industrial minerals represent. There are in excess of 30 principal industrial minerals ranging in terms of annual production from the largest quantity such as sand and gravel, to possibly the smallest quantity of production of a legitimate industrial mineral which may be defined as industrial and rough gem diamond. If we assume that it is necessary to finance independent projects of ore bodies of industrial minerals for development, the financing techniques are similar to the fundamentals that we would use for financing coal projects or metaliferrous deposits. Therefore, let's begin by redefining project financing in the traditional banking or private sector area, and then in the later development of this paper, we will apply these techniques to industrial minerals in general and cite it with several specific examples.

Jan 1, 1982

By Evan Adams

The Ireland Mine is located some seven miles South of Moundsville West Virginia, along the bank of the Ohio River. We are mining the Pittsburgh #8 seam. This seam is approximately 60" in thickness, and is immediately overlain by some 10 feet of a conglommerate material. The roof is difficult to control, due to the fact that it frequently is composed of substances not hard enough to be held together with 6-foot roof bolts. In many cases, we must use 10-foot roof bolts, in order to get bolt anchorage in the limestone above the conglommerate. Due to the elasticity of the limestone and its tendency to bend rather than to break, we have been unable to maintain a pillar line. Thus, we have found it necessary to mine by the room and pillar system. Belt haulage is used on room entries to automatic loading stations, thence into 15-ton mine cars, controlled at the loading point by car spotters. The maximum belt length is 2,000 feet. Rail haulage to the slope-bottom dump is by 27- and 50-ton locomotives. The mine produces coal two shifts per day, with 7 production crews on each shift. Mine and machinery maintenance is performed on the Midnight shift. We handle an average of 660 tons per machine shift.

Jan 1, 1964

By N. ?peh

The purpose of the paper is to present a way of assessing nonrenewable lignite resources by means of sustainability indicators. An introductory presentation of the origin and characteristics of the discussed nonrenewable natural resources is followed by the study and analysis of separate sustainability indicators. Out of many, only the ones that would directly relate to the explored coal deposit were studied. Some different viewpoints such as economic, social and environmental were assessed inside the studied landscape structure and in relation to other provincial resources using the indicators that are closely linked with the explored lignite reserves. Exploitation of coal as an underground nonrenewable natural resource, has been taking place in the ?alek valley for more than 120 years. However, about 60% of the coal will still be left underground since not all coal will have been extracted when the mine closes. According to the regional and wider national strategic goals concerning the use of natural resources and electricity production in the future, the sustainable aspect of the exploitation of the geologically well explored reserves is emphasized in the paper. Finally, we have tried to evaluate the role and the meaning of the studied underground natural resources for further sustainable development of the ?alek valley and placed stress on the most questionable spheres that should be considered preferentially.

Jan 1, 2007

By Leon Maday, Dan L. Pecha, Jeremy Johnson, Daniel N. Adams

The Brightwater conveyance system includes 26 km of tunnels, a 130 mgd pump station, 2 km of micro tunnels, and a 2.4 km outfall. The tunnels extend from Woodinville to Puget Sound through varying soils in 1 to 7 bars of hydrostatic pressure and depths to 185 m. The tunnel diameters range from 4 to 6 m and include numerous lining systems. This paper highlights major shaft and tunnel design, including dual cellshafts, multiple pipe configuration tunnels, polymer concrete segments, and the use of a one pass lining designed to convey high pressure effluent.

Jan 1, 2005

By Abou Saghafi

In order to investigate the design parameters of a future longwall in a thick coal seam a numerical model of gas emission from the goaf area was developed. A Longwall goaf was modelled as a collection of different size coal blocks. For each coal block the partial differential equation of gas flow was independently solved. In developing the flow equations, both pressure-driven and diffusion driven gas flow regimes were considered. The total gas emission rate was calculated by integrating the gas release from each individual coal block over the whole goaf area. The main output of the computer program are gas flowrate from goaf and residual content of caved coal in the goaf as a function of distance from the face. The model was applied to a longwall face driven in a thick seam where large volumes of coal in the roof were to be left behind the face. The gas contained in the coal was mainly CO, with a high desorption rate. Simulations were under- taken to quantify the effect of size of the caved coal on the flowrate from the goaf. The flow properties of coal, such as diffusivity, permeability and coal swelling due to gas adsorption, were directly measured on coal samples from the seam.

Jan 1, 1996

By A. W. Khair, S. S. Peng

Discussion by J. Parker Gentlemen; Rainy day in Upper Michigan, a good time to catch up on reading. Am doing that, and have a couple of questions concerning the K and P paper on roof problems and supports. I wonder if the authors can enlighten me. The compressive strength of the coal was reported as 4.4 MPa (633 psi) and compressive stresses measured in the coal seam were reported at around 27.6 and 48.2 MPa(4000 and 7000psi ). Can such a soft coal actually contain such a high level of stress? Can it be measured as if the material were elastic, or does the coal behave plastically? Can that stress level be confirmed with hydraulic load cells? And if the coal is so soft, and if it is plastic, why is the stress field not hydrostatic'? The intact roofrock appears to be unusually strong, with compressive strength reported at around 145 MPa (21,000 psi), and some failures were noted as soon as the rock was exposed. Were tests run to find out how that rock responded to the addition of moisture, from sprays or from humid air? Did moisture weaken the rock? Did it cause the rock to expand quickly, thus to induce internal compressive stress? How can the near-vertical cutters, as shown in the photographs, be attributed to primarily horizontal stresses? Did the cutters follow any particular pattern in the development panels, which might be related to a particular stress pattern? For example, did they always appear alongside the stiffest pillar? Or always along the northwest rib? Was there any evidence of the pillars and entries "rotating" under the influence of differential horizontal stresses? How much did the entries and pillars rotate as the longwall face approached and passed? After rooffalls, did the openings assume shapes which would indicate a preferred shape in that stressfield and geology? Did crosscuts always survive without damage, as shown in the sketch?

Jan 1, 1992

By R. J. Anderson, A. V. Castelli

In 1986, United States' barite production fell 48.9%, consumption - sold or used by grinding plants - was off 47.3%, and imports were down 63.8%. Meanwhile, world mine production decreased 29.6%, according to the US Bureau of Mines. However, value of US-produced barite FOB mine increased 46.51%, according to USBM figures. The declared value CIF US port of all imported unground barite decreased from $41.94/t ($46.23 per st) to $39.02/t ($43.01 per st). Nevada continued to be the leading US producer of barite with 69% of the total. It is followed by Georgia, Missouri, Tennessee, and California. The USBM estimates that 65% of the barite mined was used as a weighting agent in drilling fluids. The remaining 35% was used in the production of barium chemicals and as a filler. Most of the production from Missouri, Georgia, and Tennessee was used in the non-oilfield sector. This sector made up a larger percentage of the US produced barite in 1987 than it did in 1986, increasing the overall value per ton of barite. Barite consumption was at its lowest since 1963. It is estimated that 80% of the barite was consumed in the drilling fluid market. The remaining 20% was used in barium chemicals, glass, and as filler in plastics and paper. The decline of barite used in drilling fluid followed the decline in the average number rotary rigs operating - 964 versus 1968 in 1985. This was the lowest average number of rotary rigs operating since 1971. The non-oilfield market was up 5.3% in 1986. This increase can be attributed to the increased use as a filler in plastics. Imports of crude barite, though down nearly two-thirds, still made up 65% of the barite consumed in the US. China was the leading exporter to the US with 58%, followed by India, 15.4%; Morocco, 11%; Thailand, 5.4%; Mexico, 4.6%; Chile, 3.9%; and Ireland, 1.7%. Less than 1% of the imported ore was used in the nonoilfield sector. Imports of ground barite dropped from 64.4 kt (71,000 st) to 19.8 kt (21,800 st) in 1986. Of this amount, 14.1 kt (15,500 st) were used in drilling fluids in 1986 and the remainder for non-oilfield use. During 1986, more of the grinding plants supplying the drilling fluid market were closed. Dresser Magcobar and IMCO Services, a Halliburton company, formed M-I Drilling Fluids Co. Mine production in the US will probably decrease in 1987 due to the lower cost of imported ore. No significant change is expected in the drilling fluid market. The average number of operating rotary rigs is estimated at 950 in 1987 versus 965 in 1986. The nondrilling fluid markets (chemicals, glass, and filler) will follow the overall US economy. Bauxite and alumina R. J. Anderson, Ohio State University US bauxite production in 1986 dropped to a pre-World War II level, continuing a decline that began a decade ago. 1986 production totaled 450 kt (496,000 st), compared to 674 kt (743,000 st) in 1985. World production of bauxite also decreased in 1986. This reflected the soft market in alumina, aluminum, and related products. Total mine production worldwide came to 79 Mt (87 million st), down from 85 Mt (94 million st) in 1985. For the sixteenth consecutive year, Australian production of bauxite led all other sources. No other country approached the 28 Mt (31 million st) mined in Australia in 1986, despite a 4.4-Mt (4.9-million st) drop in its output from 1985. Other major producers in 1986 were: Guinea 11 Mt (12 million st), Brazil, 6.5 Mt (7 million st), Jamaica, 6.5 Mt (7 million st), and Suriname 2.8 Mt (3 million st). Despite weakness in world demand for bauxite, Venezuela, heretofore an alumina producer, is now pushing development of a new mining venture near the western border of the state of Bolivar. Plans call for barging bauxite down the Orinoco River to the Ciudad Guyana alumina plant, a distance of 650 km (400 miles).

Jan 5, 1987

By S. A. Diatchkov

There is a misconception that mineral-project economic evaluations in the former Soviet Union are either nonexistent or very limited. This is not the case. In fact, there are at least two basic methods that can be utilized to evaluate the vast mineral resources of the Commonwealth of Independent States (CIS). Evaluation procedures are based either on a comparison to known projects, which may rely on limited available data, or on potential-profit calculations, which generally uses more extensive databases. Significant philosophical differences between these systems and those utilized in the Western world include the following: •Under the centralized-government system, the economic evaluation of a mineral project was based on artificially determined mineral prices and costs. Every ten to 12 years, prices for concentrates and metals were established by the Council of Ministers and remained unchanged until the next reconsideration of prices .

Jan 1, 1995

By Thomas G. Langton

The demand for mineral raw materials, especially in the major industrialized nations, has grown rapidly during the past three decades. One consequence of this growth has been an increasing reliance by the large industrialized countries upon nondomestic mineral supplies. These mineral supplies, to a large extent, have been developed by capital from the major industrialized countries. Until recently, most foreign mining ventures were either wholly-owned subsidiaries or joint ventures between two or more mining companies. The recent rise of economic nationalism has substantially changed the business climate and parameters under which foreign investors operate. This paper describes some of the underlying reasons for this change and notes how investors have adapted to the new business conditions.

Jan 1, 1974

By G. Tiravanti

A recurrent concern in mining operations is how to deal with the large volumes of fresh water used which in turn generates large volumes of effluents that have to be treated. Water treatment can focus in one of two main strategies: treat the effluent as it is produced, or use a simulation tool to optimize water use in the process and reduce volume of effluents, contaminants concentrations, operational costs, and so on. This article shows a successful tool developed in Matlab-Simulink® that allows modelling a mining process and simulating potential improvements to evaluate the results. This tool has been proven in Cu-Mo operations and recently it has been used in poly-metallic operations. This article reviews the 4 Key Steps required to achieve our goals: a) Elaboration and verification of the mining Operation?s Block Diagram, based on a field survey; b)Model construction and input flows and qualities in selected streams; c)Model Validation and Simulation of new alternatives like recirculation, changes in reagents and dosage, partial treatment, flows merges/separation, and others; d)Development of the Optimal Solution which consists on determining the CAPEX and OPEX.

Feb 27, 2013

By S. Di Muzio

Sulphate Reducing Bacteria (SRB) are hetero-trophic anaerobic micro-organisms that can be used to remove sulphates and heavy metals from Acid Mine Drainage (AMD), heavy metal-bearing streams with high iron and sulphate contents and low pH, generated by sulphur bio-oxidation in abandoned mine districts. After the preliminary chemical precipitation of iron with carbonate stones (I step, chemical precipitation) SRB can be used to reduce sulphates to sulphurs then favouring heavy metal removal as sulphur precipitates (II step, biologically mediated precipitation). In this work the experimental results of heavy metal and sulphate removal from column tests were reported. Sulphate and heavy metal abatement in fixed bed column was performed using chemically pre-treated samples of synthetic AMD. Attenuation of toxic effects of treated samples was also ascertained by toxicological tests of germination and radical growth with Lepidium sativum.

Jan 1, 2006

By V. T. McLemore

Rare earth elements (REE) are becoming more important in our society. REE deposits are found throughout NM. Some REE past production (1950s), as bastnaesite, came from the Gallinas Mountains district, Lincoln County, NM. Several companies and the U.S. Bureau of Mines (USBM) have conducted exploration programs to identify REE potential. Four types of deposits are found in the district: epithermal REE-F veins, Cu-REE-F veins, REE-F breccia pipe and iron skarn deposits; all are associated with Tertiary peraluminous, alkaline to alkalic-calcic volcanic rocks. District zonation is defined by base metals (REE-F-Cu veins) that form center of the district, surrounded by REE-F veins. The magmatic-hydrothermal breccia pipe deposits form a belt partially surrounding the veins. Iron skarns formed at the top and edge of the trachyte intrusion and are likely the earliest stage of mineralization. In 1991-1992, USBM calculated an inferred resource of 0.487 million metric tons with a grade of 2.95% total REE. With the projected increase in demand of REE, areas such as the Gallinas Mountains district in New Mexico are being re-examined for additional REE potential.

Jan 1, 2011