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By Lee R. Kump, Sarma V. Pisupati, Peter L. Rozelle, Alan R. Larson, Timothy S. White, Nicholas A. Crescenzo, Maureen D. Feineman

The Mercer Clay bed in central Pennsylvania has produced feedstocks for the refractory industry in the USA and has also been investigated as a source of alumina and lithium. Developments in global markets for these commodities, as well as rare earth elements, have led to their classification as critical minerals in the USA, in turn renewing production opportunities for the Mercer Clay resource. The work reported here includes a review of the clay types and minerals involved, as well as past mineral processing and extractive metallurgy test work, and reports new research results from renewed investigation of the deposit as a polymetallic resource. This renewed work has found lithium contents that exceed 1,000 ppm, lying directly below the overlying Mercer coal, where the alumina content ranged from 32 to 34 wt%. Total rare earth concentrations were somewhat lower than have been found elsewhere in the region, and the highest contents were also found to be stratigraphically close to the coal. Further work is required to establish the mineral hosts for lithium and rare earths and to define the extent of enriched alumina, lithium, and rare earth concentrations.

Jul 22, 2021

By J. P. H. Steele, T. Vincent, C. Debrunner, M. Whitehorn

For a variety of reasons, the need for automation of underground mining equipment is growing dramatically, e.g., improved safety and health, availability of labor, deeper mines, and desire for more focused excavation. While there has been tremendous progress made in this direction, much needs to be done to reach the holy grail of an autonomous mining machine. This paper reviews a number of technological developments and presents research and development needs for future development. A report on our current project for the Western Mining Resource Center at CSM is included.

Jan 1, 2000

By George Vranesh

Synfuels development in the upper Colorado River basin and the population growth attendant with such development demand sizeable quantities of water. Unfortunately, the water supply in the basin is limited and such limitation may impose a significant constraint on the development of the West's abundant energy resources. Although the water for the synfuels development will be governed by the law of prior appropriation adopted in the upper basin states, the authors point out that an apparently senior water right .my not deliver a firm supply of water. The federal and Indian Reserved Water Rights Doctrine, the Colorado River Compacts the Doctrine of Equitable Apportionment, and the federal and state environmental laws can all severely diminish the value of any given water right and the synfuels industry should take care to evaluate these factors in acquiring its water.

Jan 1, 1981

By B. P. Sullivan

This paper describes how the author projected the economic benefits of a proposed coal liquefaction project based in Pennsylvania. These benefits were assessed in a successful effort to garner government support for the project. The projections considered such issues as increases in employment, wages, and tax receipts to state and local government, plus other less-obvious benefits, such as site remediation. The paper explains how sponsors of similar projects can use economic projections in making meaningful and compelling presentations to federal, state and local authorities.

Jan 1, 2000

By Z. H. Xie, D. S. He, W. M. Xie

China has rich phosphate rock resources, but with their continuous depletion, the rich ore resources have become increasingly scarce, which makes the exploration of collophane more important. Medium- and low-grade phosphate rock cannot be utilized until their impurities have been removed through mineral processing. However, due to the similar physical and chemical properties of dolomite and phosphorus minerals, the separation of dolomite from phosphate

By Tim M. Benson, Adam L. Lamanna, Carolina Martinez-Gutierrez, Mark J. Stephani

The Lower Concourse C Extension (LCE) 108-in Storm Sewer consists of a 2,797-foot long, 27 to 55-foot deep, 108-in I.D. storm sewer tunnel. Situated beneath active taxiways and a terminal apron at Hare International Airport (D), the tunnel diverts ows from existing storm sewers located within the footprint of a future satellite concourse. The project was delivered via Construction Manager at Risk (CMAR) as part of Chicago Department of Aviation’s (CDA) ongoing O’Hare 21 Capital Program. This paper presents project details, multiple stakeholder coordination, subsurface risks and challenges, TBM performance, and impacts to existing infrastructure.

Jun 23, 2024

By Yunxing Cao, Xinsheng Zhang, Bingbing Meng, Shuaifang Guo, Li Wang, Junsheng Zhang

During the initial process of mining a longwall working face, it is often found that the roof will not collapse readily, which increases the risk of later roof collapse disasters. Explosive and hydraulic fracturing are common roof weakening techniques; however, they have certain limitations. In the present study, CO2 fracturing was used for roof weakening during the initial mining phase in the Changcun coal mine, China, which is a novel strategy. First, by analyzing the lithological characteristics of the working face and applying combined beam theory, the breaking spans of the top coal, immediate roof, and main roof were determined before weakening. An F-35 CO2 fracturing device with a rated pressure of 270 MPa was used, which provides fracturing energy equivalent to 0.968 kg of TNT. The fracture radius of the main roof was studied by ANSYS/ LS-DYNA combined with the hanging roof-breaking theory to determine the optimal layout of CO2 fracturing drills. The results show that the breaking spans of the top coal, immediate roof, and main roof were reduced by 3.99 m, 7.66 m, and 22.03 m, respectively. The main roof collapsed as the working face advanced, eliminating the chance of later roof collapse disasters. Compared with hydraulic fracturing and explosives, CO2 fracturing is safer and more practical, giving it significant application potential.

Nov 23, 2023

By R. E. Hamilton

It is more than ten years since the first fully automated process using a computer started operation. Computer control has become common in a number of process industries, yet in spite of the tremendous incentives which ere present, there are only a few computer installations in the mining industry and none of these has announced successful control of a process. Recognizing that one of the reasons for this slow progress is the lack of adequate mathematical models of the various processes involved, the author's company started a project in the summer of 1966 to develop such models. It was early recognized that the existence of a major disturbance input, in the form of the mineral composition of the feed prevents most flotation plants from attaining a steady state condition. This makes the custom¬ary method of developing correlations from steady state plant data inapplicable and requires a more fundamental approach.

Jan 1, 1968

By MOHAMMAD R. H. GORAKHKI, Christopher A. Bareither, MANUEL APARICIO, Joseph Scalia IV

The focus of this study was on the evaluation of hydrologic and environmental behavior observed in GeoWaste and waste rock test piles. GeoWaste is a mixture of fast-filtered tailings and waste rock prepared as a tailings-dominated mixture. The two test piles included potentially acid-generating (PAG) waste rock and were operated for 26 months to evaluate whether GeoWaste can suppresses sulfide oxidation and production of metal-rich acid mine drainage relative to PAG waste rock. The test piles were constructed in the shape of truncated 5-m-tall pyramids with 25-m base sides and flat 5-m × 5-m top surfaces. Water content, temperature, electrical conductivity, and oxygen concentration were monitored in four layers and at five locations within each layer in both test piles. In addition, 5-m × 5-m lysimeters were installed at the base of each pile to collect leachate. Approximately 2660 mm of water was added to the surfaces of the test piles via precipitation and irrigation (irrigation ≈ 1050 mm applied at an approximately constant rate for 70 days). The measured saturation, oxygen concentration, electrical conductivity, and temperature in the GeoWaste and waste rock piles suggest more sulfide oxidation occurred in the waste rock pile compared to the GeoWaste pile. Observations from the pile experiments suggest that co-managing mine waste in the form of GeoWaste reduced acid generation compared to waste rock alone due to the lower permeability and unsaturated state of the GeoWaste pile that reduced downward migration of moisture and inhibited drainage.

Mar 31, 2021

"Cast blasting is the primary means of overburden displacement in a surface coal mine. It serves two purposes; fragmenting the rock and throwing it directly to its spoil pile using explosive energy. Increased throw minimizes costs by reducing the amount of material that needs to be rehandled. Prior studies have shown that by only changing blasthole timing with the same blast design, fragmentation and throw alter. It is necessary in cast blasting to optimize both fragmentation and throw, since larger fragments will require more wasted energy to throw the same distance. In an operating mine in Georgia, an optimum interhole delay for fragmentation has been found by studying timings from 0 millisecond (ms) to 45 ms. Instantaneous timing between holes increased the throw by more than 31 m (100 ft), but fragmentation was poor. Shock and detonation wave collision is a potential reason for this increased throw.Explosives are utilized extensively by the mining industry in order to break rock, as either ore or overburden, for hauling, loading and crushing. An effective production blast strives to achieve optimum rock fragmentation in order to increase the efficiency and reduce the costs of those downstream operations, while simultaneously meeting environmental regulations. The goal of blasting with respect to fragmentation is, according to Hettinger (2015), “to decrease the average particle size of the fragmented rock without overly increasing fines or, in other words, improve fragmentation.”Additionally, the distance the rock is transported by the explosive energy from the blast, also known as throw, can increase efficiency by reducing the amount of material that is rehandled by mine equipment. The primary situation in which this is desirable is the cast blasting of overburden across the narrow pit of a surface coal mine. A key variable in a blast design pattern that can be manipulated to optimize both fragmentation and throw is delay timing between detonations. The invention and increased utilization of electronic detonators have allowed for precise delay timings to be used between rows, holes and even multiple primers within the same hole. These recent developments in the blasting community have also provided an opportunity to investigate whether or not the mechanism of shock or detonation wave collisions caused by short timing delays are responsible for any increased fragmentation or throw. This experiment attempts to demonstrate if an increase in throw can be achieved while maintaining optimum fragmentation."

Jan 6, 2017

By P. A. Plunkert, D. E. Morse, L. McCartan, S. F. Sibley

Following the recession of 2001, restrained consumer spending, declines in domestic manufacturing and industrial output, and increased unemployment led to a lack-luster year in the domestic economy. In 2002, the U.S. real gross domestic product (GPD) grew only 2.4%. Significant production declines in the U.S. metals industry were registered by copper, lead and zinc producers. Steel producers, despite a slight improvement in shipments, continued to face strong foreign competition, higher energy costs and lower prices for their products. Homebuilding and other domestic construction sectors— major consumers of nonmetallic mineral products such as cement, brick, glass and stone — remained strong enough to help raise the output of industrial mineral materials slightly above 2001 levels. A strong U.S. dollar relative to other national currencies continued to weaken the competitive stance of U.S. metal and non-metal mineral materials companies alike against foreign producers in markets at home and abroad.

Jan 1, 2003

By J. Pascoe, J. H. van Laar, J. H. Marais, F. J. L. Matthee

Advanced measurement and verification (M&V) is a process where the impact of an energy initiative is determined in real time. Data prediction models can be used to predict and compare energy consumption with a predetermined baseline. Deeplevel mines can benefit from advanced M&V as the impact of operational changes can be identified in real time. Ultimately, this can ensure that informed decisions are made regarding energy management based on the impact and severity of the occurrence. Previous studies on advanced M&V do not account for operational changes to the model’s baseline. These changes can significantly impact the performance of both the mine and related activities. The aim of this study is to propose a method that can accurately predict the energy consumption of a deep-level mine regardless of operational changes. To achieve this objective, nine different data predictive modelling techniques were considered. The proposed method is based on the Moving Average (MA) modelling technique due to its simplicity, flexibility, and rapid development time. The coefficient of variation for the root mean square error (CV(RMSE)) was used to statistically analyse the modelling error. If the predictions exhibit an unsatisfactory CV(RMSE), the model dynamically adjusts to reduce the prediction error. The model was developed to adapt to operational changes in scenarios where the standard model becomes irrelevant. The method developed in this study was able to predict the future energy consumption of deep-level mines with an accuracy of 99%, improving the mine’s energy and finance management.

Dec 13, 2023

By Nasser Madani, SULTAN ABULKHAIR

The abstract of the paper discusses the challenge of quantifying iron content in a coal deposit in Kazakhstan. The iron dataset is limited, coming from only three drill holes and some stope samples, while a large amount of geological information is available from legacy drill hole data. The paper proposes a workflow using multiple-point geostatistics to model geological domains and two-point geostatistics to model iron content within these domains. The results show that the direct sampling (DeeSse) algorithm effectively reproduces the complex seam layers, and sequential Gaussian simulation models the iron within each domain.

Mar 30, 2022

By S. Al-Thyabat

In this work, the floatability of Jordanian phosphate slime (-38 µm) was evaluated in a batch column flotation cell, 100 cm high and 5 cm inner diameter. Flotation was conducted using sodium oleate as a collector and methyl isobutyl carbinol (MIBC) as frother. Rougher flotation yielded concentrate assaying 29.19% P2O5 with 90.29% recovery at the following flotation parameters: 2.6 cm/s superficial gas velocity, 20 ppm frother dosage, 0.205 mM collector concentration and 40% weight solids. It was also found that conditioning with the same collector dosage but with a different solids weight percent gave different flotation results. However, pulp collector concentration was the key operating parameter; increasing collector dosage at the same solids weight percent decreased flotation recovery by 3%, while increasing solids weight percent at the same collector dosage increased phosphate recovery by 18%.

Jan 1, 2011

By M. Frenzel, D. Ebert, K. Bachmann, A. D. Renno, R. Möckel, J. Gutzmer, J. Krause

With the increasing demand for metalliferous and mineral raw materials and the consequent depletion of the global natural resource base, the possible utilization of secondary raw material sources is receiving more and more attention. In the present study, we present results from a detailed vanadium deportment study of three basic oxygen furnace slag (BOS) samples known to containing elevated bulk concentrations of vanadium. Complementary analytical methods that were used to quantify the abundance and composition of V-containing phases include SEM-based automated mineralogy, X-ray fluorescence analysis, and X-ray powder diffraction as well as electron probe microanalysis. The vanadium deportment was quantified using Monte-Carlo simulations of the data obtained from automated mineralogy and electron microprobe analysis. The total V concentrations identified by XRF are between 1.7 and 2.2 wt.% V. The most important hosts of vanadium are larnite-, brownmillerite- and portlandite-solid solutions. In two samples Ca carbonates also significantly contribute to the V deportment, while wuestite, lime, and native iron do not contribute significantly to the vanadium deportment. A thorough consistency check identifies considerable uncertainties in the density of the V-bearing phases as the most likely reason to explain remaining discrepancies between measured and calculated V values.

Oct 14, 2023

By Tianzu Yang, Weifeng Liu, Lin Chen, BOYI XIE, DUCHAO ZHANG, HUI XIAO

The oxygen-rich bath smelting process of copper dross was simulated using Factsage software. It was found that the two-step simulation results agreed better with the industrial data, especially in the speiss. Bi, Pb, Sb, As, and Cu contents in the speiss by two-step simulation differed from the industrial data by 0.6 wt.%, 0.8 wt.%, 2.6 wt.%, 7.2 wt.%, and 8.6 wt.%, respectively. Twostep simulation results indicated that the speiss partitioning of Sb, As, and Cu increased from 60.1%, 32.3%, and 27.5%to 81.6%, 67.8%, and 47.2%, respectively, with the smelting temperature increasing from 1050 °C to 1250 °C. While the metal partitioning of Sb and Cu increased from 0% and 2.7% to 15.2% and 13.3%, respectively, with the separation temperature increasing from 400 °C to 700 °C.

Oct 19, 2020

By Laura Suarez, Jörgen Kajberg, Pär Jonsén

In recent years, slag, a residue from pyrometallurgical processes, has become more attractive in circular economy frameworks to increase the efficient use of resources throughout the life cycle of steel products and help in the reduction of carbon emissions. Its applicability is strongly dependent on the particle size, and therefore, the optimization of breaking processes should be approached by increasing the knowledge of the dynamics of slag to promote fracture. Increasing the knowledge on themechanical response ofmanganese slag opens up the potential for the development of cost-effective numerical models, e.g., constitutive models based on inverse engineering calibration frameworks or digital twins. In this study, rate-dependent tests of manganese slag have been performed using a split Hopkinson pressure bar device for testing its dynamic mechanical response. In order to obtain information about the crack initiation and fracture process, 2D ultra-high speed imaging was implemented with a sampling frequency of 663,200 fps for diametrically loaded specimens. Full-field deformation measurements using digital image correlation (DIC) techniques showed a staggered fracture process where failure points on mechanical response curves vary due to the internal events happening in the material. Localized frictional occurrences and inertial effects acting inside the pre-cracked matrix have a strong effect on the global mechanical response, and therefore, a great variability of strengths was obtained.

Nov 3, 2023

By Viktor Lishchuk, Olof Martinsson, Tobias E. Bauer, Elena Haller

Freely accessible and non-confidential real-life geological data sets from mineral deposits are desirable for the wide range of applications in research and education. However, publicly available statistical data are limited in their number and quality—they contain reduced information about geological, geophysical, geotechnical, chemical, mineralogical, and other relevant properties of deposits. This makes such data insufficient for scientific purposes. However, the amount of geological knowledge obtained for a variety of deposits in the past allows the construction of an idealized synthetic ore body model using analytical approach. Such a model could be used for education purposes and testing basic scientific theories, e.g., visualization of deposit structure; teaching sampling strategies; testing new algorithms for mine planning; or comparing geostatistical modeling methods. This paper presents an analytical approach to simulate volcanic massive sulfide (VMS) deposits and shows how synthetic deposit model can be constructed and further used for studying sampling with drilling and simulating folding and faulting.

Jan 14, 2021

By Stephanie Singarayer, Damodara Reddy Chinnasane, Mike Yao, Danielle Pelletier

Mining at Vale’s Creighton Mine has been active for nearly 120 years in Sudbury, Ontario, Canada. Being the deepest mine in the Sudbury region, mining induced seismicity is a common occurrence at Creighton Mine. Over the past five years, 26 large magnitude seismic events ranging from 2.5 Mn to 3.7 Mn (Nuttli) have occurred. Out of these large magnitude events, three 3.0+ Mn events occurred between April 2020 and January 2021. The majority of the 3.0+ Mn events are believed to be the fault-slip type that could be linked to the known major geological structures and/or long-term effect of mining over many years. The recent large magnitude events are believed to be triggered by high induced stresses while mining the first few stopes of a new lower horizon in the top-down centre out mining sequence.

Apr 26, 2022

By Siddhartha Roy, Hemant Agrawal, Ram Madhab Bhattacharjee, Devi Prasad Mishra

Heat stress in underground coal mines is a major threat to the health and safety of the miners. Hence, managing heat and prediction of heat stress in advance is essential for maintaining a safe, healthy, and productive underground mine environment. In this study, an extensive ventilation survey has been carried out in three different deep and mechanized underground coal mines. The ventilation survey data are used to develop 3D simulation models with the VentSim™ software to predict the conditions that could cause heat stress in underground mine workings. The developed 3D models predicted well the wet-bulb globe temperature (WBGT), a recognized indicator of potential heat stress, with a coefficient of determination (R2) of 0.986, 0.994, and 0.993 for Mine-A, Mine-B, and Mine-C, respectively. Moreover, through 3D modelling, the applications of auxiliary ventilation and spot coolers to reduce the wet-bulb globe temperature (WBGT) for improving the underground workplace environment have been explored. The study demonstrated that auxiliary ventilation and spot coolers can help in significant reduction of heat stress conditions in an underground mine environment. By application of auxiliary ventilation, to increase air volumes, and spot coolers, the WBGT index in mining faces is reduced by 1.2–1.4 °C and 3.9–5.4 °C, respectively. Therefore, it is concluded that the spot coolers are more effective in reducing the heat stress conditions in hot and humid underground mine environments in comparison with auxiliary fan that is used to increase the air volume and velocity. This study opens up a new horizon of 3D simulations for heat stress management in underground mines. The outcome of this study will be useful for the researchers, mine operators, and environmentalists understanding the heat stress contributors and their control in underground mine environment.

May 10, 2023