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By R. M. Powers

The Florida Institute of Phosphate Research (FIPR) has funded a four-year research project to develop a computer model 'which will predict the hydrologic impacts of phosphate mining on surface and groundwater systems. The core of the model is an analytical geographic information system (SPANS) which integrates EPA's Hydrology Simulation Program Fortran (HSPF) surface water model with the McDonald-Harbaugh groundwater model (MODFLOW). The hydrologic model conducts both event and continuous annual Simulations driven by variable precipitation and temperature data. The model is currently being calibrated and will be ready for distribution to the user community in mid-1991.

Jan 1, 1990

By Raymond F. Moran

The history and development of the FMC Coke process has been reported in numerous presentations over the past 10 years (1, 2, 3, 4, 5, 6) but a short review is desirable, especially regarding the aspects that are influenced by the coal to be used. F'MC has been developing this process in pilot facilities since 1956 and in a modest sized plant in Kemmerer, Wyoming since 1960 (Figure I). This plant produces strong uniformly sized coke briquettes from a completely non-coking coal, namely Elkol, a sub-bituminous coal of the Adaville seam. Since operating commercially, over 300,000 tons have been produced, 90% of which has been used in electric phosphorus furnaces and some 10% of which went for trials in iron blast furnaces. We believe that this commercial use of non-coking coals is a unique experience in the history of coke manufacture.

Jan 1, 1975

By G. Pan

A geostatistical approach is proposed for the design of infill drilling programs. The method is consisted of three major steps: developing geological favorability models, delineating mineralization and ore envelopes, and classifying reserves or resources. Geological modeling aims at developing favorable geological zones in which drilling is designed. Modeling mineralization and ore envelopes establishes criteria on potential blocks to be drilled. Top target blocks should be those included within ore envelopes. The framework of resource categories includes five types: probable reserves, indicated reserves, indicated resources, possible resources, and barren. Indicated reserves or resources are the top priority to be drilled for the definition of minable reserves. Possible resources may be considered as targets for further exploration. The algorithms involved in the analysis include indicator favorablity analysis, ordinary kriging, and indicator kriging. A case study presented here involves a gold deposit of Carlin type. The deposit was delineated by a sparse drilling program with 230 feet of average spacing. The infill drilling program designed by the new method suggests a significant reduction on the number of holes from a regular-grid infill drilling pattern.

Jan 1, 1995

By P. J. Bethell

In the froth flotation process the detrimental effect of slimes on the froth flotability of valuable minerals has long been known.1 Work by Aplan2 on the froth flotation of coal has shown that the presence of clay slimes causes loss in flotation selectivity, and recovery of combustibles. Obviously then the presence of clay slimes to any great extent in the froth cell feed in a coal preparation plant is undesirable. This problem is exacerbated in plants treating raw 600 um (28#) by zero material due to the variation in flotation with size. The net effect of this phenomenon in a bank of cells treating raw minus 600 µm (28#) material s that by the time adequate flotation of the coarsest size fractions has occurred the finer sizes are already producing undesirable high ash material, which often leads to unacceptable overall quality. Reduction in aeration rate and/or chemical addition to combat this, further decreases the flotation rate of the coarsest fraction leading to heavy losses of coarse low ash coal to the tailings. The above mentioned characteristics formed a key aspect of the fine coal circuitry design at Elk Run Coal Company in Sylvester, WV. The plant was designed to produce compliance steam coal (less than 1.20 lbs. S02/million b.t.u.) Desliming ahead of the froth flotation was included, as the slimes in the plant feed were clay rich, had very high ash levels, and low potential recovery. Lab testwork had also shown that poor selectivity would be expected if raw minus 600 um (28#) material was froth floated.

Jan 1, 1986

By Richard Emberley, Timothy Shaw, José L. Torero, Jurij Karlovsek, Timothy Gibson

"Tunnel closures are highly undesirable and the lengthiest are generally attributed to structural failures (e.g. Mont Blanc). Although historical data shows structural failures are closely linked to fire, design parameters for tunnel safety are not well defined. Current research has focused on defining the fire heat release rate and temperature, but these parameters cannot be easily used to determined structural performance. The energy transferred to the structure, the heat flux, is required but current literature lacks these values. Full scale experiments were undertaken on passenger vehicles resulting in heat fluxes between 20-70kW/m2. Analysis shows a vehicle fire’s duration is closely linked to its mass. Further analysis shows small vehicle fires can be scaled as a function of the tunnel diameter and the characteristic height of the desired vehicle. The present work provides engineers an appropriate design methodology to undertake informed thermal-structural analysis to minimize the risk of tunnel structural failure.INTRODUCTION Quantifying the effects of a tunnel fire depends on many factors such as the type of occupants, their vehicles and spacing, ventilation conditions and the geometric shape of the tunnel (Ingason and Lonnermark 2011). For design engineers investigating the thermal-structural performance of a tunnel, these factors are typically converted into spatial and temporal temperature distributions (Usmani et al. 2001) using various design curves such as those of ISO834-1, Hydrocarbon, Rijkswaterstaat (RWS) or RABT-ZTV (Promat 2013). However, to define a temperature profile through a structural element these curves require a heat transfer model that incorporates an appropriate boundary condition. The appropriate boundary condition is the net heat flux which is the result of a complex energy balance. For use in heat transfer calculations the net heat flux must account for the tunnel geometry as well as thermal properties of a given structural element and all other surfaces and mediums affecting the transfer of heat (Torero 2014)."

Jan 1, 2016

By A. D. Rovig

Metallurgical evaluation of autogenous grinding of Anaconda's Berkeley Pit ores indicated that tonnage throughput increases, at a finer flotation feed size, were possible by converting autogenaus mills to steel ball mills. In addition, initial test work showed that the improved grind resulted in slight recovery gains in subsequent flotation processing.

Jan 1, 1974

By H. H. Murray

Abstract. World reserves of bauxite are abundant. Domestic reserves are limited and as a consequence the United States must rely on foreign suppliers for over 90 percent of its bauxite. Nationalization of many bauxite mining operations, levying of higher taxes, increased production and transportation costs, and attempts to create a uniform market price combined to place the United States in a vulnerable position. Alumina from kaolin, alunite, anorthosite, and oil shale have-been-or are being evaluated. World bauxite reserves are increasing and attempts to establish a uniform price have failed; therefore, it may be many years before domestic non-bauxite sources of alumina can compete with imported foreign bauxite.

Jan 1, 1980

By George W. Heunisch

The properties of Neutra-Fix® and Neutra-Ment® , two new lime substitutes for the treatment of acid mine drainage (Arm), have been compared with lime and Alkament®, two products presently in use for AMD treatment. The two new products are basically dolomitic byproducts and produce sludges that are more compact than those from lime. Sludge settling rates are faster than lime with iron concentrations after 24 hours that comply with EPA regulations. Material utilization and optimum pit are reported.

Jan 1, 1984

By R. K. Mensah-Biney, M. T. Hepworth, K. J. Reid

The loading characteristics of gold-bromide species onto activated carbon were evaluated using a batch system. The overall loading of gold onto activated carbon was rapid for the first few hours, but it continued without cessation as a result of the reduction of gold. Therefore, conventional equilibrium considerations were not applicable. Although loading continued slowly after several days, an abnormally high, loading capacity value of 10-12 meq/g carbon (650-800 kg Au/t) could be attained in 72 hours. The loading of gold-bromo species by activated carbon was by the mass transfer of (AuBr4)- species to the external surface to be reduced to metallic gold by carbon. Elution of gold from loaded carbon was feasible provided the carbon had not been loaded to high capacity values. If loading is carried to high levels, complete elution becomes impractical, and the gold may be recovered by ashing the carbon. For the high loading capacities observed, this option would appear to be cost effective. The effect of several variables on the loading capacity of the activated carbon for gold-bromo species is discussed.

Jan 1, 1994

By Rosario Lunar, Jesús Martínez-Frías, Egidio Marino, Trinidad Torres, Jose E. Ortiz, Juan A. Martín-Rubí, Luis Somoza, Ricardo León, Teresa Medialdea, Javier González

Seamounts, submarine banks, volcanoes and undercurrent channels are prominent geomorphic features that have become an important target for minerals research and exploration with the goal of future exploitation. Polymetallic ferromanganese deposits are common types of mineralization on these settings. Co-rich ferromanganese crusts are important as potential resources of Mn and Co, but also Ti, Ni, Tl, REEs, PGEs, and other metals. Many seamounts and channels along the Atlantic Spanish continental margin are known to hold mineral deposits but are poorly studied. This work presents and briefly describes the most recent activities of the Spanish Geological Survey (IGME) on exploration and investigation of ferromanganese deposits along the Atlantic Spanish continental margin. Different submarine areas from the northwestern margin of the Iberian Peninsula to the west off Canary Islands have been surveyed by geophysical, sampling and underwater observations from 89 to 4000 m water depth. The mineral deposits cover a large diversity of submarine geological and geomorphical features: mud volcanoes and diapirs related to hydrocarbon seeps, seamounts associated with hot spot volcanism, hydrothermal vents in active magmatic volcanoes, structural basement highs and banks or contourite channels. Considering the collected dataset, we present the preliminary results of the study of these mineral deposits, including ferromanganese nodules and crusts and phosphate pavements and nodules, which can be considered as potential sources of raw materials.

Sep 1, 2014

By YONGQIONG YANG, Ning Wang, CHONGGUANG LUO, LI ZHU, Hanjie Wen, SHENGJIANG DU, Hannian Gu

Niobium in kaolin clay from the Late Permian sequences was reported in the range of several hundreds of micrograms per gram and was considered as a potential resource for its high concentrations and large areal distribution. Ti-bearing minerals associated with kaolin clay were identified as the main host phase for niobium in some case studies. However, the correlation between the concentration of niobium and titanium is poor, and the types of Ti-bearing minerals and modes of occurrence of niobium are not clear. Typical kaolin clay samples from the Late Permian sequences from southwest China were characterized, and the final products derived from kaolin clay sample were investigated using XRF, ICP-MS, XRD, SEM, and TEM (EDS). The results reveal that there were three types of TiO2 mineral phases in the clay samples: (a) massive TiO2 minerals and (b) aggregates of nano TiO2 minerals did not contain niobium while (c) granular TiO2 minerals were the source of niobium from the EDS analysis. The granular TiO2 minerals included anatase and rutile, both of which were the sources of niobium in kaolin clay in the current study. The findings are of great theoretical implication for source and origin study of Ti-bearing minerals and guidance for separation and recovery of niobium from kaolin clay.

Nov 30, 2020

By William Hodder, Ehsan Alavi, Nader Ghasempour, Daniel Cressman

The Don River & Central Waterfront Coxwell Sanitary Bypass Tunnel (CBT) Project in Toronto will extend approximately 10.5 km from Ashbridges Bay Treatment Plant west under Lake Shore Boulevard, north under Bayview Avenue and east through the Don River park area to the Coxwell Ravine Park. The tunnel is currently being mined by using a shielded dual-mode tunnel boring machine (open and close) capable of operating in EPB mode and lined by using a precast concrete segmental tunnel linear with an internal diameter of 6,300 mm and external diameter of 6,900 mm. The CBT is expected to be excavated mainly through shale bedrock of the Georgian Bay Formation, at approximately 50 meters deep. The tunnel crosses a buried bedrock valley in two locations, in the southern portion of the alignment, adjacent to the Don River, and at the northern portion of the alignment approaching the CX-1 shaft. In these two locations, the bedrock cover is expected to be less than 6 meters. The risk of encountering weathered bedrock, significant ground water inflows or surficial soil deposits through these buried valleys was identified during the design phase. The contract required the TBM to be designed with the ability to probe drill ahead of the TBM and convert to EPB mode if necessary, to cross this area. This paper will discuss the additional exploration that was performed by the contractor to identify the extent of this buried valley, the plan going into the zone of potential weathered shale, and the actual conditions encountered.

Jun 13, 2021

By Ross Goodman, Jesse Salai

The Ohio River Tunnel Project encountered multiple unexpected geotechnical challenges such as crown and invert instability due to the overstress condition affecting the strata above, below, and in the tunnel alignment during and after TBM excavation along with the potential for methane inflow. This paper showcases how the orientation of a tunnel alignment has a significant impact on how in-situ geological stress can impact the excavation of a tunnel from the contractor’s point of view and how geological features influence gas inflow to the alignment over time.

Jun 13, 2021

By Roland Arnold, Richard Gradnik, Martin Zeindl

This paper presents the details of the Kramer tunnel project in the Federal State of Bavaria, Germany. This road tunnel, which has been under construction since December 2019, is the key component of the western bypass of the town of GarmischPartenkirchen. Once completed, it will relieve the town’s central district from enormous volumes of traffic. The contractor is the joint venture named ARGE Kramertunnel consisting of BeMo Tunnelling and Subterra. The whole project will be completed and handed over to the project owner, Staatliches Bauamt Weilheim, in 2023. The opening of the entire bypass section including the tunnel to traffic is planned for 2024. The tunnel, with a total length of 3,609 m (2.24 miles) and an estimated cost of EUR 178 million (incl. VAT), is designed as a single-tube, double-lane structure with one traffic lane for each direction of travel. The safety issue that exists for single-tube tunnels is solved by a parallel escape tunnel passable for vehicles. All tunnels and ducts are excavated according to the principles of the New Austrian Tunnelling Method (NATM). In order to reduce the geological risk for the owner, the escape tunnel was supposed to be completed before the design process for the main tunnel ever began. The exploratory tunnel was awarded to a competitor with an separate contract.

Jun 13, 2021

By N. Damiano, C. Zhou, R. Jacksha, J. Srednicki

Modern electronic devices and systems used to enhance miner safety and health are becoming commonplace in underground coal mines. The ability for these devices and systems to function properly in the presence of electromagnetic emissions from other electronic and electrical devices and systems is not entirely understood. To investigate potential electromagnetic compatibility issues of critical mine electronic devices and systems, researchers from the National Institute for Occupational Safety and Health (NIOSH) are conducting surveys of electromagnetic emissions in underground coal mines. This paper presents the measurement system, methods, and results of electric field electromagnetic emission surveys conducted in three underground coal mine environments in the frequency range of 10 kHz to 1000 MHz. The survey data show that in some environments electric field electromagnetic emissions in underground coal mines approached or slightly exceeded limits as defined by other industrial sectors.

Mar 2, 2022

By Evan J. Owen, Virginia T. McLemore

There are tens of thousands of inactive mine features in 274 mining districts in New Mexico (including coal, uranium, metals, and industrial minerals districts). However, many of these mines have not been inventoried or prioritized for reclamation. Many of these mines have existing mine wastes, generated during mineral production, which could have potential for critical minerals, especially since the actual mineral production was generally for precious and base metals and not critical minerals. The purpose of this project is to characterize and estimate the critical mineral endowment of mine wastes and “beta-test” USGS sampling procedures. This project is important to the state of New Mexico because critical mineral resources must be identified before land exchanges, withdrawals or other land use decisions are made by government officials. Future mining of mine wastes that potentially contain critical minerals will directly benefit the economy of New Mexico. Possible re-mining of mine wastes could clean up these sites and pay for reclamation. Furthermore, this project will include training of younger, professional geologists and students in economic and reclamation geology by the PIs.

Feb 1, 2024

By Zohreh Kazemi Motlagh, Virginia T. McLemore

Critical minerals are nonfuel minerals, essential to the U.S. economy and national security, whose supply chain may be disrupted. Mine wastes are potential sources of critical minerals. The goal of this project is to estimate and characterize critical minerals endowment in three mining districts in New Mexico: Black Hawk (Grant County), Hillsboro (Sierra County), and Magdalena (Socorro County), and assess their acid-generating potential. The Black Hawk district is an arsenide five-element vein deposit (Ag, Ni, Co, As, U, Bi, and local minerals like Pb, Cu, Zn, W, and Sn). The Copper Flat mine in Hillsboro district is a copper porphyry deposit. The Kelly mine in Magdalena was first mined at 1878 and are carbonate-hosted Pb-Zn deposits. Mine waste rock piles and tailings are sampled using USGS Beta sampling procedure. Geochemistry results show that Black Hawk district mine wastes samples are elevated in Ag (>200 ppm), Co (290 ppm), Ni (2,130 ppm), and Zn (8,463 ppm). Copper Flat mine tailing is elevated in Bi (111 ppm), Cu (7,453 ppm), and Zn (2,360 ppm). Downhole profile plots in Copper Flat show the positive correlation between Cu, S and Te values. Magdalena samples are elevated in Cu (5,700 ppm), Zn (129,500 ppm), and Pb (58,100 ppm). Determination of acid-generating potential in these areas suggests that Black Hawk district mine wastes are non-acid-forming while high S present in some Copper Flat and Magdalena samples can potentially cause acid mine drainage.

Feb 1, 2025

By Kevin Saeler, Patrick Willaman

Utilizing automation is one way to improve competitiveness. Roof and rib bolting in underground coal mines has not changed significantly for more than 40 years. Most roof bolting is still a largely manual process involving high levels of staff carrying out repetitive work. Roof bolting statistically has one of the highest levels of underground accidents, including finger, hand, and arm injuries. Operators are exposed to falling objects and becoming entangled in roof bolting apparatus while roughly moving awkward 6-ft drill steels and roof bolts. It is estimated that over 25 million roof bolts are installed annually in the U.S. underground coal market with well over 1,500 operators involved in roof bolting on a day-to-day basis. Recently electrohydraulic roof bolting rigs have been installed to offer partial automation of the drilling cycle and the bolting cycle. The next stage is to provide a storage and loading system to allow full automation of fullcolumn resin roof bolts. This paper reviews the latest electrohydraulic roof bolting equipment and discusses the testing of a fully automated drill rig. Full electronic control allows each step of the roof bolting process to be recorded, providing a digital record of each installation, including hole depth, spin time, gel time, torque, and cycle time. Other benefits include monitoring of water pressure and flow, used to prevent blocked drill steels as well as digital fault finding. A fully automated roof bolting machine greatly improves operator safety and gives high-quality repeatable roof bolting with reduced cycle times.

Jul 1, 2023

By Gary B. Glass

In 1997, 92.3% or 235.7 Mt (259.8 million st) of coal produced in Wyoming came from the Wyodak coal zone in the eastern Powder River coalfield. The mined portions of the zone consist of one to three beds of coal with an aggregate thickness between 15 and 33.5 m (50 and 110 ft). The thickest expression is 61 m (200 ft). The delivered coal from this zone averages 0.33% sulfur, 5.12% ash and 19.98 MJ/kg (8,590 Btu/lb.). This coal zone occurs at or near the top of the Paleocene Fort Union Formation, which is overlain by the Eocene Wasatch Formation. There is also production from two coalbeds in the lower portion of the Wasatch at the southern end of the basin. Production of coalbed methane derived from the Wyodak coal zone is currently an estimated 289 Mm3/a (10.2 billion cu ft/year). This production is occurring west and downdip from the coal mines and is increasing each year.

Jan 1, 1998

By Robert W. Bruhn

State and federal regulations require that surface mine overburden be investigated in advance of mining for naturally occurring earth materials that are detrimental to animal and plant life or to uses of water. Proper identification of these toxic materials is necessary to permit development of environmentally sound reclamation programs. Intensified use of present laboratory methods to meet anticipated testing demands would be both costly and time consuming. This paper discusses the desirability of and general requirements for a geophysical system capable of locating toxic zones in the overburden of surface mineable lands of the Northern Great Plains Coal Province. The paper (1) identifies the types and character of naturally occurring overburden substances that must be investigated in advance of mining, (2) discusses the economic justification for development of a geophysical system to replace or to complement conventional laboratory test methods, and (3) discusses the potential applicability of downhole geophysical methods to overburden analysis.

Jan 1, 1981