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By P. A. Rittenhouse

Reserves of potash are more than adequate to meet future world demand for this primary fertilizer nutrient. The bulk of both reserves and current production is located in only a few countries. Recent attention has focused on potential development of smaller reserves to supply local markets in developing areas of the world. However, most new capacity in the next decade will be built in countries with large current production and reserves. The paper reviews current and future projects that will add to the world supply of potash.

Jan 1, 1985

By Doug Harding

The Metropolitan St. Louis Water District’s Project Clear is a 28-year program targeting wastewater capacity throughout St. Louis, MO. The extensive program includes the Jefferson Barracks Tunnel, running parallel to the Mississippi River at 2 m ID and 5,400 m long. A rebuilt Robbins Main Beam TBM began boring but hit challenging conditions about 2,400 m in, including water inflows. A larger 4.1 m Robbins Main Beam machine will complete the remaining 3,050 m in limestone, dolomite, and shale. The TBM will utilize a high-powered, high breakout torque cutterhead along with enhanced 360-degree probing & grouting capabilities to detect any karst formations.

Dec 1, 2022

By H. Vigil Fernandez, G. Peach

The Musaimeer pump station and outfall project located in Doha Qatar, was designed to collect and manage ground and stormwater and then discharge the treated waters offshore. The project constructed a long outfall tunnel using an EPB TBM with segmental lining, each tunnel ring being 1.35 m in length with an internal diameter of 3.7 m.. The diffuser structure was a 6-arm structure, measuring 294m by 40 m connected to a central manifold in turn connected to the TBM constructed tunnel via a riser shaft drilled from an off-shore barge. This technical paper will discuss the planning, methodology and construction practices employed to connect the TBM tunnel to the diffuser structure 10.2 km offshore.

Jun 13, 2023

By M. R. Haibach, M. L. Shema, J. M. Silvis

"Since 2005, longwall coal mine operators in Pennsylvania (US) have been required to collect extensive hydrologic and biological data to document pre- and post-mining conditions of aquatic resources (streams and wetlands) overlying the subsidence control plan areas. Continued operation of the longwall mine is dependent upon empirical data demonstrating that the undermined aquatic resources have either been maintained or restored to an accepted range of pre-mining conditions. This study used quantitative hydrologic methods and comparative biological metrics to examine response of aquatic resources to longwall subsidence at the Bailey Mine located in Greene County, Pennsylvania. This study analyzed data from over 25 miles of streams and over 8 acres of wetlands that traverse the 4,779-acre study area. Hydrologic analysis of flow intermittency suggested that there are variable degrees of change to headwater streams immediately following mining; however, the majority of the effects are reversible through streamflow mitigation measures. Furthermore, the post-mining discharge from streams can be restored to within the range of pre-mining conditions the majority of the time. Biological assessments showed that greater than 95% of assessed stream length has maintained its ability to support benthic macroinvertebrate communities following mining and intervention (i.e., mitigation). Comparative metrics of the benthic macroinvertebrate communities showed that the biological community in 48 of the 50 sample sites is being maintained or restored across both high- and low-gradient streams. The effectiveness of intervention was further substantiated by the similarity in recovery times between streams having no intervention (median = 2.1 years, 95th percentile = 4.9 years) and streams with intervention, when recovery times were measured from the date of the intervention (median = 1.7 years, 95th percentile = 4.7 years). Changes to individual wetlands were observed between the pre- and post-mining assessments, but cumulatively a net gain of 7% in wetland acreage was realized. Hydrologic assessments were used to infer whether there was a potential that streams had been affected by mining; however, the ultimate test of stream recovery is based on biological metrics that establish the relative quality of the biological communities following mining. Overall, the hydrologic balance is being protected and the aquatic life use of streams is being maintained within the Bailey Mine’s subsidence control plan areas."

Jan 1, 2017

By S. Mohanan, C. R. Kumar, S. K. Bhoja, T. Venugopalan

"A pressing issue that has often been the topic of discussion in iron-making operations in India is the high content of alumina in the country’s iron ore deposits. The presence of alumina has hampered production by affecting slag fluidity, and thereby the hot metal quality. Iron ores from Indian mines are generally rich in hematite, with traces or small amounts of goethite/limonite, kaolinite, gibbsite and quartz reported from time to time. In day-to-day production, emphasis is placed on checking the chemical analysis of product samples, but the true solution to the alumina problem lies in estimating the mineralogy of the ore samples. We developed a mathematical model, based on singular value decomposition, to predict mineralogy from classical chemical analysis. We then used X-ray diffraction patterns, scanning electron microscope analysis, and grain counting with an optical microscope to determine actual mineral compositions and to test the values predicted by the model. The results indicate that with regular calibration, the model can be used as a simple, fast and effective tool to predict on a regular basis the mineralogy of multiple samples.IntroductionIndian blast furnaces use high-grade iron ores (as lumps or as sinter) and coke (obtained from the destructive distillation of coal) as raw materials for the production of high-quality hot metal to be converted into different steel products through the Linz- Donawitz process. The iron ores are mainly sourced from the Singhbhum region of Odisha and Jharkhand states, the Bailadialla region of Chattisgarh state and the Bellary region of Karnataka and Goa states, and are mainly classified based on size as (1) lump ore (fed directly into blast furnaces), (2) fines (converted into sinter/pellets and fed to blast furnaces) and (3) slimes (< 0.15 mm; currently dumped in huge slime ponds). Any variation in the quality of the ores supplied results in variations in the production trends of hot metal."

Jan 1, 2015

By I. M. Arbuthnot

Over the last five years, a large number of small to medium sized carbon-in-pulp gold treatment plants have been built in Australia, most designed to treat between 250,000 -1,500,000 tpa of ore. In many cases, the primary requirement was to get a plant built and operating in a short period of time and at minimal capital cost, relating to the limited capital resources and tight cash flow positions of these relatively small mining companies. Since the inclusion of both pre-leach and tailings thickeners resulted in an obvious and significant capital cost, most plants were built without thickeners, without doing a detailed cost-benefit analysis on their inclusion, However, the increasing use of High Rate Thickener?s (HRT s) in the mineral processing industries resulted in a reassessment, in some cases, because of their considerably lower cost. This reassessment was triggered primarily by the need to conserve water in arid mining areas, where borefields were costly to install and water was limited. It has become apparent, though, since startup and operation of these installations, that the savings in cyanide consumption is also a very significant factor and can be used as a primary justification for the installation of a HRT in many cases.

Jan 1, 1991

By James O. Mawyer

Fuel is a major .cost for power generating utilities. Virginia Power is completing one of the nation&apos;s largest coal reconversion programs. As a result, 10 million tons of coal will now be used at six generating stations. Four of these stations are located on naviagable waterways. They consume over half of Virginia Power&apos;s coal. Historically, railroads have exclusively served these plants. In an effort to substantially reduce fuel cost, Virginia Power has reexamined transportation logistics and is proceeding with barge delivery. A phased approach was used by Virginia Power for the transportation program. Plant requirements were first identified. Coal sourcing issues were then examined. The concept of intermodal transportation was investigated. The bottom line cost savings was used as the criteria for continuing the project. The results thus far have been gratifying. Virginia Power has begun to implement barge transportation.

Jan 1, 1986

By J. M. King

A crucial step in the acquisition by one company of the assets of another, the acquisition of the stock of another company, or the merger of two com-ponies, is the legal due diligence which needs to be performed in order for the acquirer to ascertain or confirm the obligations, liabilities and exposures to risk that are being assumed along with the assets or corporate stock being acquired. Where the obligations, liabilities, or exposures to risk arise from existing contracts, or from pending lawsuits, administrative proceedings, or threats of these actions, those matters are relatively straightforward to discover by careful review of the files of the party whose assets or stock is being acquired. However, where a company is engaged in ongoing mining or processing operations and has operated or owned mining proper-. ties, there are many sources of liability and exposure to risk which could have major adverse economic consequences to the acquiring party and which are not revealed, or at least are not clearly delineated, by the records of the company whose stock or assets are being acquired.

Jan 1, 1990

By W. C. Dailey

The Groveland Mine. Concentrator and Pellet Plant are located in Dickinson County in the Upper Peninsula of Michigan. The construction of the Groveland Mine in 1959 was the first United States operation for the Hanna Mining Company in mining and beneficiating low grade iron formations. (1) The plant produced concentrates at 675,000 lt/yr. (746,600 mt/yr.) which was used as sinter feed in the steel industry from 1959 to 1963. Upon completion of a pelletizing plant in April, 1963 production increased to 1.6 million lt/yr (1.77 million mt/yr) of pellets. After the plant expansion, mill capacity increased to 2.2 million 1t/yr (2.43 million mt/yr.), producing 2.0 million It/yr (2.23. million mt/yr.) of pellets assaying 63.0% iron and 7.0% silica. (1) Prior to April, 1971 the concentrator operated with a flowsheet consisting of spirals and a petroleum sultonate iron notation circuit. This was presented in a paper by R. R. Smith and E. E. Sougstad, "Flotation at the Groveland Mine" in the 50th Anniversary Volume entitled "Froth Flotation". The ore body at the Groveland Mine consists basically of two types of iron formation (34% total iron, 20% magnetic iron head), the most abundant of which is a bedded magnetite-chert-silicate rock. This is intermingled to varying degrees with non-bedded to poorly bedded hematite-clastic quartz-chert rock. (1) In developing the Groveland flowsheet, Humphrey spirals were used because of their ability to produce a coarse size concentrate at a low cost. Tests run in the lab and pilot plant on the Groveland ore showed a. spiral weight recovery in the 27 to 33% range. (2) However as the ore body was opened up, it became evident that the most abundant ore type did not liberate at the coarse size fraction needed for spirals. Plant recoveries for the first five years operating the spirals only averaged from 10 to 15% weight recovery. In 1971 the weight recovery on the spirals had dropped to a low of 5%. To increase iron recovery and at the same time increase plant capacity with the least effect on the present operations the mill flaw-sheet proceeded from a spiral-notation circuit to an all flotation circuit to a magnetic separator-flotation circuit. During this changeover the concentrate grade also had to be improved to meet market demands. To do this the following changes evolved

Jan 1, 1978

By S. -Y. Hwang

An ongoing problem for industry in Korea is effective removal of heavy metals from and safe disposal of spent power plant fly ash. This research endeavor attempts to develop selective separation of Ni from leach liquor using a selective chemical precipitation method. The research was conducted by changing two variables, the pH and the concentration of ions in solution. The effect of other ions present in the system on the separation efficiency of Ni species was also investigated by adjusting OH and NH3 concentrations. In the pH range of 7-9, the chemical precipitation method produced a high yield of Ni by precipitation from the fly ash leach liquor.

Jan 1, 2010

By Richard E. Ray

Conventional concrete block plastered with a cemantitious coating is the most common material used in the construction of perma¬nent stoppings to direct airflow in underground mines in the U.S.A. All mines experience various degrees of strata convergence depending upon depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting in significant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overhead to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating "Max-Seal" polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased several-fold in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

Jan 1, 1984

By T. R. Ellis

Many appraisers/valuers believe that the only valuation method available within the cost approach category for real property appraisal is the depreciated replacement cost method. Some valuation and financial reporting standards setters also believe the same. This paper introduces the minerals appraiser to a number of useful methods for mineral property appraisal that are based primarily on the principle of contribution to value, the predominant economic principle in the cost approach. Most of these cost approach methods discussed are primarily for use in valuation of exploration tracts and resource properties that have no defined reserves. However, the powerful rural cost method can be used to calculate the contribution of categories of resources, reserves and other property components to the value of a mineral property. This method can be applied to mineral properties at all stages of development, including producing properties. The author reasons that standards and regulations pertaining to real property valuation should be modified, and underlying principles should be expanded, so as not to inhibit appropriate application of these cost approach methods.

Jan 1, 2011

By George J. Skoronski

The economics of pellet plant operation, in terms of fuel and power consumption, flexibility in the selection of the cheapest fuel source, system availability, maintenance costs, and the simplicity of process design, contribute to the determination of building and profitably operating a pellet plant. Design innovations, sup- ported by actual field data, have been initiated into the GRATE-KILN System design to positively address these factors. This paper presents the recent state of the art design concepts which have helped the GRATE- KILN System assume worldwide acceptance status.

Jan 1, 1983

By Onur Golbası, Berk Gokce

Investment decisions in the mining industry are complicated by sector-specific uncertainties. This study presents a multi-submodule system dynamics model to capture the dynamic complexities of decision-making across mineral property development stages. The model includes five interconnected subsystems: valuation, production, growth strategy, demand, and finance. Developed through system decomposition, expert input, and literature, the model is tested on a hypothetical copper mine with 850 ktpa capacity and 1% cu grade. Simulated over five years with quarterly steps, it estimates an enterprise value of $78.9 million and a target growth rate of 11.2%. Results highlight the significant effects of operating costs, capital policies, and inflation on free cash flow, and the critical role of mineral reserves in sustaining growth. This model supports strategic investment analysis across different minerals and development phases, offering mining investors a robust tool for optimizing decisions.

Feb 22, 2026

By S. Mojeddifar, N. Ostadmahdi Aragh, M. Hemmati Chegeni

This work integrated selective principal component analysis (SPCA) with a singularity fractal model to map hydrothermal alterations of argillic, phyllic, and propylitic in the north-west of Kerman city in Iran. SPCA results were provided for short wave infrared (SWIR) bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor tomap phyllic and propylitic alterations. Also, the bands 5–7 were applied to map the argillic alteration zone. SPCA results could present useful information for alteration mapping but it does not show the purest pixels of alteration. Therefore, a fractal model of singularity was applied to highlight the different alteration pixels in the Kerman Cenozoic magmatic arc (KCMA). Thus, the singularity index of different hydrothermal alteration zones was produced. Comparing the obtained results with the field data showed that Kader, Serenu,Meiduk, and Abdar deposits were acceptably identified by alteration mapping. Also, it seems that the singularity index could not discriminate the hydrothermal alterations of argillic and phyllic. The same spectral signature of kaolinite and muscovite minerals is the main reason for misclassifications.

Jul 20, 2020

By Ralph L. Merklin

One of the most commonly employed set of calculations in mill design and research is the material balance, known in wet beneficiation plants, as an Ore and Water Balance. For mill designers, the balance is one of the principal requirements in determining the proper size of launders, pipelines, process equipment, etc. In process development, one of the major goals is the establishment of an optimum balance. The usual procedure for calculating a material balance involves a manual technique utilizing reference tables, pre -obtained data, and a slide rule or desk calculator. With these, the engineer must perform a series of calculations which are repetitious in nature and time consuming. Figure I is the flowsheet of the grinding and flotation circuits for a copper concentrator. The initial ore and water balance was calculated manually and required approximately 24 manhours. Later, a number of changes were made in the balance, each of which required an average of 8 manhours.

Jan 1, 1967

By Thomas Konstantis, Spyridon Konstantis, Panagiotis Spyridis

"Tunneling and Underground works are unequivocally subject to a diversity of inherent uncertainties associated with the geotechnical, hydro-geological and environmental regime that surrounds them. On many occasions, these uncertainties can provoke loss events of considerable consequences. The present contribution elaborates on losses that the insurance market has suffered in the recent years, following a construction failure event. These losses are being considered and analysed on a quantitative basis through evaluation of cost related data, with explicit discretization of the applied construction methodology and of the subsequent developed failure type since both of which are considered of major importance. Given the identified persistence and regularity of some loss-contributing factors, recommendations are provided on the basis of a proactive risk engineering management approach that are envisaged to reinforce the understanding of project risks and alleviate the incurred insurance cost. 1 INTRODUCTION The underground construction sector has always been a very challenging area for all involved parties, including the insurance market. Main reason for that remains the uniqueness of the uncertainties sources and the subsequent inherent risks that the tunneling and underground projects are exposed to. In many instances, these risks materialize, leading to loss events with substantially high impact on reinstatement cost and incurred delays, which depending among others on the insurance coverage will have to be bared by the Insurance market. In the recent decades and as the tunneling industry boomed and expanded with many major and significant projects undertaken around the world, the insurance market was faced with additional challenges. Increased competition during tender coupled with the scale and complexity of the projects and politically driven decision making exerted pressure on the project timelines, completion dates and budget. The pressure for on-time or even early project completion- to avoid liquidated damages or achieve bonus payments, respectively- along with cost reduction efforts and the incentive for innovative failure events. That, in turn, put additional pressure on the Insurance market which had experienced a significant amount of losses with substantial cost. One of the triggered mitigation actions was the introduction of the Code of Practice for Risk Management of Tunnel Works (ITIG, 2006 & 2012; MunichRe 2006, Wannick, 2007, Spencer, 2008, Adeyemo, 2011)."

Jan 1, 2016

By Reynold Q. Shotts

Underground mines, penetrating well below the water table, quickly fill with water when abandoned. Ordinarily, these natural cisterns are not thought of as sources of industrial water. Under special circumstance, if chemically treatable, they might become valuable industrial water reservoirs. An example of a group of about 20 mines in a geological and structural setting insuring water entrapment, rapid recharge and a possible minimum of contamination, are the small, compact Belle Ellen and Piper basins in Alabama&apos;s small but second most productive coalfield, the Cahaba. The mines have been abandoned from more than 50 to less than three years. The county now produces about a million tons of coal annually, all from strip mining. Figure 1 shows an idealized cross section of the strata in the Belle Ellen syncline near West Blocton, Bibb County, Alabama. Figure 2, 3 and 4 are maps showing the location of the syncline, other structural features, the outcrop lines of the three principal coalbeds underlying the basin, and the mined-out areas on the three beds (1).

Jan 1, 1973

By E. Molleman

This paper reports on testwork exploring the dissolution/reprecipitation reaction: ZnS + 2HCl ? ZnCl2 + H2S, as part of a process for the production of pure ZnS. In spheroidal form, this would constitute a premium fonn of zinc refinery roaster feed enabling the production of pure ZnO. The research focused on the influence of proton activity on dissolution of zinc concentrates from Brunswick Mining & Smelting, Red Dog and Tara. The results and thermodynamic data suggest that the three concentrates contained significant amounts of the more reactive mineral wurtzite, although XRD analysis showed mainly the presence of the mineral sphalerite.

Jan 1, 1997

By Terry A. Rightnour

Multiple seam mining is predominant throughout the central Pennsylvania Appalachian coal fields. Wide ranges in individual seam thickness, coal quality, and overburden characteristics are common throughout the region. On typical mining permits, ranging from 404 x 103 to 2023 x 103 m2 (100 to 500 acres), often as many as eight seams are concurrently mined, with each interburden requiring unique economic and environmental consideration in the mine plan. Specifically, this paper presents several planning tools and operational guidelines developed in response to current regulations for the special handling of potentially acid-forming materials as they are related to development and operation of multiple seam mines.

Jan 1, 1984