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By Ken A. Phillips

Like the Arizona jeans commercial says: Arizona's not just a state, its a state of mines. Nearly 300 mines operate in Arizona making it the largest nonfuel mining state in the nation. Although copper is king in Arizona's mineral complex, nonmetallic minerals play important roles both regionally and nationally. Throughout Arizona's mineral resource development history industrial minerals have dominated over the metals for most, but not recent years. The State's metal mining industry which makes Arizona the number one mining state in the United States is a relatively young phenomenon. Arizona was an important industrial mineral producer long before her metal mining industry got started. Salt, phosphates, silicates, and oxides as food additives, tanning chemicals, gemstones, components of aboriginal ordnance, pigments, and construction materials are among the minerals produced long before copper, gold, silver, and the other metals became important. Around 92 % of Arizona's mineral industry is made up of nonfuel minerals, 86 % of that is accounted for by copper. Another 4 % is taken up by copper byproducts of molybdenum, silver, and gold. The remaining 10% of the production is occupied by non-fuel, non-metallic minerals. Arizona's 1994 industrial mineral production of nearly $380 million ranks us among the top 25 in the nation and higher than the total mineral production of at least 15 states.

Jan 1, 1996

By George E. Edwards

Pacific Rim markets for export coal already represent a larger market than the total tonnage imported into the European Community countries and they will continue to expand. The largest importers will continue to be in the sector comprising Japan, Korea, Hong Kong and Tai- wan. It is likely that the total Pacific Rim markets will reach 206 m.t.p.a. by 1990 and 290 m.t.p.a. by 2000, with the major growth in steam coal demand. Australia has an efficient coal industry, represents a stable long term source of supply and is favourably situated geographically to continue to be the largest single supply source.

Jan 1, 1982

By T. Rudolph, M. Pawlik, J. Benndorf, X. Yin, J. F. Brune, P. Goerke-Mallet

The long and often undefined period in the post-mining phase challenges geo-monitoring with its various responsibilities, like the detection of environmental changes, ground movements and water management. Modern methods of geo- and environmental monitoring observe numerous aspects using active and passive sensors with multispectral, hyperspectral and microwave sensors, with diverse spatial dimensions and spatiotemporal resolutions from satellites, Unmanned Aerial Vehicles (UAVs), in-situ sensors. Data integration, together with on-site knowledge and experience, provides the basis for comprehensive modeling, which improves the understanding of the environmental changes and their related causes, which is an essential step for public acceptance. In this paper, we aim to give a brief overview of various geo- and environmental monitoring methods.

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 VASU GANGRADE, Marcia Harris, Kumar Vaibhav Raj, Jim Addis, Khaled Mohamed, Snigdha Sarkar

The National Institute for Occupational Safety and Health (NIOSH) conducted a ventilation assessment for a recently established underground room-and-pillar stone mine implementing split-mine ventilation. The primary objective was to examine the impact of the length of the in-place stone stoppings on face ventilation efficiency. These stone stoppings serve to separate the intake and exhaust entries and align with the mining direction. To achieve this, computational fluid dynamics (CFD) modeling was utilized. The appropriate turbulence model was selected, and a mesh convergence analysis was conducted for the CFD model. Following that, the CFD model was validated using the conducted ventilation surveys. Two configurations of in-place stone stoppings, designated as Layout-I and Layout-II, were simulated using the validated CFD models. Layout-I featured a shorter in-place stone stopping, while Layout-II had a longer one. The results obtained from the CFD models demonstrated that the increased length of the in-place stone stopping in Layout-II resulted in a notable enhancement in ventilation efficiency at the advanced faces (last stopping), elevating it from 4% in Layout-I to 8.4% in Layout-II. However, no significant impact of the in-place stopping layouts was observed at other faces. In general, Layout-II exhibited a greater circulation of air at the outby stoppings.

Feb 1, 2024

By Zainab Nasrullah, MontanaFrank Agyemang, Mehran Sadat, Richard LaDouceur

Rare earth elements (REEs) are valuable for various modern technological applications, including metallurgy, machine building, radio electronics, instrument engineering, nuclear engineering, and manufacturing. The extraction and separa-tion of rare earth elements (REEs) from their complex ores is challenging due to their distinct physical and chemical properties, contributing to their market scarcity. At present, REE recovery utilizes traditional pyro- or hydrometallurgi-cal processes. The overall process in the recovery and sepa-ration of individual elements from complex REE systems suffers from high energy demands and the use of many haz-ardous chemicals that negatively impact the environment. With the growing trend toward a circular economy aim-ing to balance sustainability, efficiency, and environmental impacts, this research is focused on using deep eutectic sol-vents (DESs): a combination of a quaternary salt: Choline Chloride and five organic acids: Oxalic Acid, Urea, and Ethylene Glycol, Lactic acid and Glycerol for the selective leaching of REEs from their complex ore which is proven to be green, selective, non-toxic, biodegradable, and cheap. The effects of different DESs and leaching time on the REE leaching efficiency were determined, and the optimum DES media were found to be Oxaline and Lactic Acid at which a leaching efficiency of 25% and 15% was achieved at 80°C respectively for cerium.

Feb 1, 2025

By Verya Nasri, Behrouz Esmaeilkhanian, Mohammad Motallebi

Réseau Express Métropolitain (REM) is the new Light Rail Transit (LRT) network of Montreal, Canada. This new LRT network uses a century-old Mont Royal Tunnel (MRT) to connect Downtown Montreal to the north side of the Island of Montreal by passing through Mount Royal Mountain. This railway double track horseshoe tunnel is approximately 5 km (3.1 mi.) long, 8.8 m (29 ft.) wide and 5.5 m (18 ft.) high, with a constant 0.6% grade. Due to different geological characteristics of the surrounding ground, varied from hard rock to soft soil, different cross sections and excavation methods were adopted for construction of this tunnel. In order to use MRT in the modern transit system, the tunnel needed to be inspected, rehabilitated and be compliant to the recent safety standards. This paper presents a summary of history and characteristics of the existing tunnel plus the implemented steps to upgrade the tunnel. It includes the details of the structural inspection and rehabilitation methods of the tunnel. Further, this paper summarizes the procedures for the space proong, construction of the separation center wall, and the tunnel enlargement. It also describes parts of complications encountered during the construction and solutions implemented to tackle these issues.

Jun 23, 2024

By James Carroll, Lance Heyer

This paper describes the shaft design and construction for a 72-inch microtunnel under 14 active railroad tracks in Avondale, Louisiana. Initial shaft design for a deeper tunnel alignment considered secant piles with a jet grout plug. Final design for a shallower tunnel alignment included contractor input with support consisting of braced sheet piles with a jet grout plug. The authors further elaborate on jet grout implementation in very soft organic clay soils and the practical limitations of jet grouting. This paper emphasizes how all project participants worked together to utilize value engineering and alternative delivery on a unique tunneling project with a focus on temporary shaft support.

Jun 23, 2024

By Ross K. Digby

The Victorian Tunnelling Centre (VTC) has evolved its purpose from purely training workers, to a tunnelling industry education city. The VTC has now focused its activities on the areas of technology; education and training; applied research; and career education. were identied as the hus around which activities would e conducted to create a tunnelling industry education city. The VTC provides ustralias tunnelling industry with an education facility that not only provides laour training, ut enales the industry to come together to meet, participate in product launches, undertake research, work with new technologies and promote tunnelling careers.

Jun 23, 2024

By Augusto Andres Torres Toledo, João Felipe Coimbra Leite Costa, Luciano Nunes Capponi, Diego Machado Marques

Short-term mine planning to open pit requires defining diglines to orientate the excavation geometry. In deposits with multiple chemical variables, it is necessary to have more rigorous control over the feeding of the processing plant. This study analyzes the impact of incorporating multiple chemical variables, the risks generated by geological uncertainty, and the number and starting point locations of shovels in the sequential design of diglines. The objective is to maintain and preserve the low-grade variability, required tonnage, and continuity in sequentially selecting blocks. To achieve this, the probability distribution function of each chemical variable is used while attempting to maintain the ore grades as constant as possible. As it is difficult to maintain multiple elements with low variability simultaneously, the relevance of each chemical variable in the economic benefit is identified. Weights are assigned to signal the importance of each element based on its significance in the recovery process. Several diglines, consisting of sequential blocks, were generated on the same seed point to meet the weekly ore demand. Optimizing the stationarity of multiple chemical variables, accessing and reducing the geological uncertainty performed through geostatistical simulation of grades and transfers functions, considering the number and location of shovels, while meeting the operational restrictions of the selected blocks. The optimized digline with the multiple grades as stationary as possible is retained. The process is illustrated in a phosphate mine. The results show that the proposed method is viable and allows for a quick solution.

Jun 25, 2023

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 P. K. Kankar, Manoj Khandelwal, Ramesht Shukla

One of the utmost severe mining catastrophes in underground hard rock mines is rock burst phenomena. It can lead to damage to mine openings and equipment as well as trigger accidents or even threat to life as well. Due to this, a number of researchers are forced to study some easy-to-use alternative methods to predict the rock burst occurrence. Nevertheless, due to the extremely multifaceted relation between mechanical, geological and geometric factors of the mines, the conventional prediction methods are not able to produce accurate results. With the expansion of machine learning methods, a revolution in the rock burst occurrence has become imaginable. In present study, three machine learning methods, namely XGBoost, decision tree and support vector machine, are utilized to predict the occurrence of rock burst in various underground projects. A total of 134 rock burst events were gathered together from various published literatures comprising maximum tangential stress (MTS), elastic energy index (EEI), uniaxial compressive strength and uniaxial tensile stress (UTS) that have been used to develop various machine learning models. The performance of machine learning methods is evaluated based on the accuracy, sensitivity and specificity of the rock burst prediction.

Mar 17, 2021

By Kostas Kaklis, Zach Agioutantis, Robin Flattery

Pillars are used as the primary support structures for underground mining to maintain stability by supporting the over laying strata. In the case of horizontal seams, the pillars are typically subjected to axial loading due to the weight of the overburden and/or abutment stresses, while in the case of inclined seams they are subjected to oblique loading due to both the vertical and horizontal in-situ stress.

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

There are several methods (empirical, statistical, and machine learning tools) to calculate blast-induced ground vibration. Still, due to complications in the blasting procedure, under varying blasting loads and strata conditions, it is not easy to predict and simulate blast vibration precisely. Therefore, a study was conducted to simulate the field blast data in Ansys software using explicit dynamics. For this study, monitoring of ground vibration for 20 single hole blasts was carried out. The density of emulsion explosives was in the range of 0.9 to 1.15 g/cc. In the laboratory, rock properties were determined from the rock sample collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and the density of the emulsion explosive were also determined. These parameters were used for numerical analysis to know the ground vibrations at specified points. The results of ground vibration predicted by the model are validated using field data.

By J. Andrew McGlenn, Brian McInnes, Bruce Downing, Murray Gant

The Second Narrows Water Supply Tunnel crossing beneath Burrard Inlet is an important component of the Greater Vancouver Water District’s plans to increase seismic resilience and meet increasing water demands. The project included the 110-meterdeep (350 ft) South TBM Receival Shaft, one of the deepest shafts to date in the sedimentary rock unit underlying much of Metro Vancouver. The shaft encountered varied sedimentary rock types, including fractured rock, with accompanying high groundwater inflows. This paper discusses the design and construction challenges associated with this shaft and the necessary means to complete the shaft in time for TBM arrival.

Jun 13, 2023

By Kyle Amoroso, Larry Applegate, Aaron K. McCain

The use of frozen soil as ground improvement and temporary ground support for the excavation and construction of cross passages and adits has gained in popularity over the last decade. Frozen soil provides a number of advantages for this application such as being waterproof, structurally stable, and working well with any soil type. One of the greatest advantages is the ability for the system to be adaptable to the project geometry and site limitations. Multiple case histories illustrate that freezing can occur from the ground surface, from within the tunnel, or as a combination.

Jun 13, 2023

By GRANT COLLIGAN, BROCK O’KELLEY, Corby Anderson

With the world’s ever-expanding push to expand technological capabilities, the need for specialized materials including rare earth elements has exploded. One source found in the USA is bastnaesite, a rare earth bearing fluorocarbonate mineral, currently mined at the Mountain Pass Mine in California. To increase production, it is essential to optimize existing processes and create new ones to better utilize current resources. Therefore, a US Department of Energy Critical Materials Institute sponsored research program was carried out at the Kroll Institute for Extractive Metallurgy to expand the fundamental understanding of the industrial bastnaesite concentrate leaching system. With the help of prior knowledge, thermodynamic calculations and design of experimentation based lab testing, a novel single-stage hydrochloric leach system was created to optimize the rare earth extraction from bastnaesite. Historically, the existing industrial process has utilized a two-stage leach system involving a high-temperature hydrochloric acid leach with liquid solid separations followed by a caustic crack stage of the leach residues. A series of single-stage leach experiments were run by reacting locked cycle flotation concentrates with hydrochloric acid to test common leaching parameters. The results of these patent pending single-stage tests have shown rare earth recoveries significantly higher than reported recoveries of historic two-stage caustic crack processes, all while decreasing the equipment required and the type and amount of reagents needed.

Jan 31, 2022

By P. Kim Carroll, D. Nick Tiffany, Doyl M. Fritz

Thunder Basin Coal Company received the 1987 Wyoming Excellence in Surface Mining Award for construction of the State's first major sediment control reservoir to be designed using the new settleable sol ids standard. Use of this standard resulted in construction cost savings of more than $250,000; reduced water quality monitoring; enhanced downstream channel stability because of more natural sediment loading; allowed simultaneous establishment of permanent waterfowl and fisheries habitat; and provided a quality recreational site. This article will address factors associated with the design and construction of that sediment reservoir and the benefits that were realized. (Note: This paper was originally published in the proceedings for the 1988 National Symposium on Mining, Hydro1ogy, Sedimentology and Reclamation held in Reno, Nevada, December 5-9, 1988.)

Jan 1, 1989

By Tim Lundquist

Disa Technologies Inc. provides innovative, sustainable solutions for mineral processing and remediation through its patented High-Pressure Slurry Ablation (HPSA) technology. HPSA processes solid feed material in slurry form, propelled by high pressure pumps through opposing nozzles that generate impinging jets within a collision housing. This process induces particle-to-particle collisions in a high energy zone, creating intergranular fractures along grain boundaries. In our batch scale and continuous operating testing, we have found that controlling key processing variables such as nozzle velocity, slurry solids percentage, and the number of passes can allow for controlled size reduction and maximum mineral liberation. Since 2018, Disa Technologies has demonstrated the versatility of HPSA by testing it on diverse materials, including phosphate, copper, uranium, vanadium, zinc, rare earth elements, lithium, nickel, mineral sands, gold tailings, and more. The intent of this paper is to present an overview of our test results describing in detail impacts on size reduction, recovery, and grade with a focus on HPSA's adaptability across ore types. Looking forward, it explores the potential to process materials such as DR-grade iron, clay, PGMs, bauxite, and various tailings. Additionally, it examines planned advancements in HPSA technology, including optimized nozzle spacing, higher capacity models, improved tonnage-to-footprint ratios, enhanced maintenance features, and expanded nozzle configurations.

Jan 1, 2025