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By Jeong-Heum Kim, Jan M. Mutmansky, Y. J. Wang

The simulation of randomness in a system of components is important in certain types of systems analyses. This paper presents procedures for generating ventilation networks that are random in many of their characteristics and which can be used to study the performance characteristics of various mine ventilation network analysis procedures without introducing undue bias as a result of the nature of the network. Among the parameters of a network that affect the efficiency of a network analysis procedure are: (1) the interconnection pattern of airways, (2) the distribution of resistances in the network, (3) the number and location of fans, (4) the fan characteristic curve, (5) the size of the network (number of branches), and (6) the density of the network (number of nodes compared with the number of branches). In the procedures proposed here, a single fan with a fixed characteristic is used to simplify the problem and eliminate the fan as a source of variation. The resistances of the airways, the pattern of interconnection of the airways, and the fan location are randomly chosen in an attempt to eliminate the bias in the performance characteristics of the network analysis methods caused by these parameters. A method of generating biconnected networks while keeping the "randomness" of these other parameters is suggested. At the same time, the size and the density of networks are controlled to investigate their impacts on the performances of the network analysis procedures. The combination of these two variables has been termed the "level of complexity" of the network in this paper. Finally, a summary and conclusions section outlines some characteristics of the networks generated, using the random generation procedures outlined in the paper.

Jan 1, 1991

By Rainer Antretter

While respirable crystalline silica (RCS) dust that arises in industrial production mostly emanates from point sources and can be well mitigated, the extraction of dust is much more difficult in underground construction, since locally generated dust spreads widely. Analysis of dust measurements shows that RCS values are difficult to predict, and effective dedusting systems are required to comply with permissible exposure limits (PEL) in breathed air. Dedusting systems are effective near the tunnel face, while dedusting of working areas away from the tunnel face is difficult or even impossible. In general, there is little temporal influence on the tunnelling work—except for drill and blast excavation—which makes it necessary to remove the deduster and ductwork from the face area. Concurrent work in the tunnel is affected by the backflowing air mass of ventilation and therefore the quality of this air mass must be considered. The use of personal protective equipment (PPE), e.g., dust filter masks, is considered the least-desirable safety measure available. However, for certain individual operations in the tunnelling process, the use of PPE cannot be avoided, especially if other technical mitigation measures are not possible. In tunnels with small cross sections for example, dedusting systems often cannot be accommodated and PPE must be used instead. This raises the question of whether the use of PPE can be avoided by designing appropriate excavation cross sections and allowing for the implementation of technically engineered mitigation measures. The paper highlights problems with dedusting measures and shows possible ways to achieve OSHA compliance.

Jun 13, 2021

By Pieter Berendsen

Lamproite occurs in two locations in southeastern Kansas that are in close proximity to each other. In both locations, the lamproite is restricted to north- east-elongated, ellipsoidal depressions measuring about 3 mi by 1.5 mi. At the surface and in the shallow subsurface, lamproite occurs as sills that were intruded into Middle and Upper Pennsylvanian rocks consisting of shale, limestone, and minor sandstone. Isotopic age determinations by Zartman and others (1967) indicate that the lamproite was intruded during the Late Cretaceous (88-91 my). Drillholes for hydrocarbon exploration down to a depth of about 1,400 ft (top of the Mississippian) and numerous shallow drillholes (mostly 200-300 ft) by the Kansas Geological Survey in the northern portion of Silver City dome helped to understand the structural complexity and extent of the near-surface sills. Numerous radial faults showing small apparent vertical offsets limit the lateral continuation of individual sills. Concentric faults are believed to mark the edge of the depression. Wagner (1954) mapped the geology of Silver City dome in considerable detail and recognized a northward dipping, 120-ft-thick, lamproite sill exposed at the surface along the northeastern edge of the dome. The upper 40-50 ft of the sill weathers olive-brown and has a soft, clayey consistency in which only the phlogopite mica is recognizable. The weathered material has been mined by Micro-Lite LLC since 1982 from the exposed sill in an open-pit that measures about half a mile extending in an east- west direction. The bulk of the material, about 98%, is used as an additive in mineral supplements for cattle feed.

Jan 1, 1999

By Thornton L. Neathery

A small area in the Alabama Piedmont was studied to determine if metallic enrichment was associated with local magnetic anomalies. Cores from two holes in these magnetic anomalous areas have sulfide (pyrite, pyrrhotite, chalcopyrite) film on slicken-side and fracture surfaces. Two hundred and fifty soil samples were collected from the top of the "B" horizon on 1, 000 foot centers over the general trend of magnetic anomalies. Soil samples were leached with a 1:2. 7 mixture of HF and H2SO4 and the dilute filtrate analyzed for Cu, Pb, Zn, Ni, Co, Cr, Mo, and Cd, using atomic absorption methods. Concentration-value maps were prepared for each element. Small areas of anomalous concentrations were defined for Cu, Pb, Zn, Mo, and Ni. Some of these areas generally coincides with magnetic anomalies. Concentration values (ppm) range from: Cu 165.0 - 0. 5; Pb 265. 0 - 0.0; Zn 1386.0 - 43. 0; Ni 187.0 - 10.0; Co 207.0 - 6. 5; Cr 117.5 - 2.0; Mo 95.0 - 0.0; and Cd 32. 5 - 2.0. Studies of other magnetic anomalies appear warranted.

Jan 1, 1972

By R. Gray, B. Hebblewhite

Experience from Australia had identified what is referred to as nonconventional surface subsidence behavior. This occurs under irregular surface topography, resulting in valley closure, valley floor uplift or “upsidence,” and far-field horizontal movements, occurring even beyond conventional “angle of draw” limits. This paper discusses such behavior recently observed in Pennsylvania and focuses on the 2005 case of Duke Lake Dam in Ryerson Station State Park. In July 2005, there was a significant increase in water leakage through a number of growing cracks in the dam, leading to the dam being breached to avoid an uncontrolled failure. An underground longwall mine was located approximately 900 ft to the north, mining at depths of 330 to 720 ft. Investigations, including a subsequent ground movement monitoring program, found a range of evidence in the vicinity suggesting that valley closure and farfield horizontal movements may have occurred, resulting from the adjacent mining. Besides discussing the phenomenon of nonconventional subsidence behavior and the Ryerson State Park case study, this paper includes an assessment of the mining, geology and subsidence impacts and suggested ground behavioral mechanisms.

Jan 1, 2015

By Roberto de Moraes

Lunar construction faces unique challenges arising from the nature of regolith and megaregolith. Unlike terrestrial soils shaped by weathering, lunar regolith is composed of angular, poorly sorted particles produced by impacts, with bulk Density, strength, and trafficability varying sharply with depth and terrain. Boulder fields, floaters, and talus aprons add further complexity, disrupting excavation and mobility. Apollo missions documented these conditions through drive-tube samples, trenching, penetrometer data, trafficability tests, and seismic profiling, but the results remained as datasets rather than a unifying classification. This paper introduces the LRC (Lunar Regolith Classification) Framework and the Overconsolidation Ratio applied for the Moon (OCR*), the first contractor-ready system to organize Apollo-derived trends into excavation demand zones (L1–L5). LRC is explicitly a classification, not a stratigraphy: depth ranges are indicative and require in-situ verification before use. Each zone is defined by bulk density and strength ranges, field proxies (bootprints, trench stability, auger torque, seismic contrasts), and corresponding excavation implications. Worked examples from Apollo 15 (mare), Apollo 16 (highlands), and Apollo 17 (pyroclastics and talus) demonstrate how observed data translate into LRC zones. These cases show that LRC captures both systematic depth trends and sharp local heterogeneity. The framework standardizes excavation planning for landing pads, haul roads, berms, foundations, and tunneling trials, while converting floaters from hazards into resources. LRC thus provides a common language for lunar construction. Rooted in Apollo evidence but designed for Artemis verification, it is proposed as a living standard; a reference framework to guide site preparation, excavation, and risk management in the next phase of lunar development.

Feb 22, 2026

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 Biswajit Samanta, Pranjal Pathak

A multimine mineral value chain (MVC) consists of multiple mines in the upstream supplying raw materials to multiple destinations in the downstream. The short-term mine production scheduling problem of a multimine MVC aims to determine the optimal extraction sequence and destination allocation of blocks from all the mines collaboratively to meet the quality and quantity requirements of all the processing plants in each period, subject to all relevant technical and operational constraints of the mining system. It is carried out at shorter scales of days/weeks/months under the purview of long-term production scheduling. An optimal short-term production schedule for MVC involving multiple mines that share the same infrastructure (processing units, stockpiles and waste dumps) requires coordination across the network of mines. Optimizing the short-term production schedules independently at each mine fails to capture the benefit of collaboratively generating schedules for all the mines, resulting in suboptimal schedules. Additionally, in short-term production scheduling, the operations are modeled in greater detail with additional decision variables and constraints to model the more complex multimine MVC situations. This makes the large-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. This work presents a customized genetic algorithm (GA)-based heuristic approach to obtain near-optimal solutions to the industrial-scale instances of the short-term production scheduling problem of multimine MVC within a reasonable computation time.

Oct 1, 2022

By C. O. Petter

This paper, in its first part, compares the profile and economic weight in the extraction of industrial minerals and aggregates to the so called conventional mining activities (metals, coal, gas and oil extraction) in Brazil. In its second part, a descriptive analysis of the present situation of the education in Brazil is made, emphasizing the graduation and post-graduation formation especially in engineering. The curricular structure of the schools that prepare the mining workforce is discussed and the presence of specific subjects in industrial minerals is evaluated. Finally, considerations are made on the actions being taken in the main universities and companies, aiming to improve the formation of the specialized workforce. The Brazilian mining production, comparing 2010 to 2011 showed an expansion of more than 3% (IBGE, 2012). Not bad, but nothing to do with the 13% growth between 2010 and 2009 (influenced by a recovery effect from the 2008 commodities? nightmare). The commodities that had a rising behavior were titanium, gypsum, nickel, graphite, bauxite, phosphate, chrome and chrysotile. All of them were eclipsed by the impressive growth of iron ore production. Some decreases could be noticed, eg. in zinc, kaolin, magnesite and salt production (DNPM, 2012). In fact, the mining activities followed the positive growth of the country these last 5 years. The commercial balance (exports against imports) was not spectacular (positive in US$ 30 billion in 2010). It is important to notice that the mineral commodities balance was US$ 35 billion, representing 27.4% of the total exports and 15.6% of the total imports of Brazil (DNPM, 2012). In this positive environment, the workforce in Brazil showed progress in number of formal jobs and average revenues.

Feb 23, 2014

By A. J. Teske

Sustainable Development is a very broad initiative in the mining industry, with major components running over the entire life of the mine. It likely commences with pre-exploration permitting and continues to post-mining final closure and possible land reuse. Most major mining corporations embrace the sustainability initiative, either out of a sense of social responsibility or out of necessity in order to continue doing business. But many may view the overall initiative as an added ?cost of doing business.? In many elements of sustainability, there clearly can be added cost ? some as simple as complying with self-imposed sustainability reporting. Fortunately, one major element of sustainable development can clearly be shown to reduce costs ? energy resource management. This paper will describe how the mining industry sustainable development effort differs from other industries, but can benefit from their experience in energy resource management. The mining industry can utilize proven methods from other industries to further their energy management efforts. In addition, many of the resources developed and employed to promote better energy resource management in non-mining industrial settings will be listed.

Jan 1, 2010

By Mahiyar Nasarwanji, Jonathan K. Hrica, Jonisha P. Pollard, Lydia M. Kocher, Brianna M. Eiter

Within the metal/nonmetal mining sector, fall-related incidents account for a large proportion of fatal and non-fatal injuries. However, the events and contributing factors leading up to these incidents have not been fully investigated. To help provide a clearer picture of these factors, an analysis of imminent danger orders issued by the Mine Safety and Health Administration (MSHA) between 2010 and 2017 at both surface and underground metal/nonmetal mine sites revealed that most orders are associated with fall risks. Of these cases, 84% involved the workers not using fall protection, fall protection not being provided, or the improper use of fall protection. Fall risks for workers most frequently occurred when standing on mobile equipment, performing maintenance and repairs on plant equipment, or working near highwalls. In most cases, a single, basic, corrective action (e.g., using fall protection) would have allowed workers to perform the task safely. Overall, these findings suggest that a systematic approach is needed to identify, eliminate, and prevent imminent danger situations. Furthermore, to protect mineworkers from falls from height, frequently performed tasks requiring fall protection should be redesigned to eliminate the reliance on personal fall protection.

By John W. Goth

This article, though not common feature material, should be of reader interest. Goth made this presentation as the keynote address at the 19th Annual Intermountain Minerals Conference in Vail, CO, in August. Introduction Working backward, what is an LDC? LDC stands for Less Developed Country. LDCs play a dynamic role in world supply and demand of basic materials. They occupy an equally important position in international marketing and finance. I will explain later some of my concerns with LDCs. First, I want to address an issue I think is of equal or even greater concern. Mining and High Technology Unfortunately, many people believe that America must make a decision now between being a smokestack-based economy or a high-technology-based economy. Some would have you believe that smokestack America is dead. Our only option is to turn to high technology, in a manner similar to countries such as Japan. Presumably, when we talk about high-technology industries we envision organizations that came into being within the last decade or so and incorporate microelectronics, biotechnology, and interconnected computers. The entire workforce is clad in lab coats and there are few employees in proportion to the work performed. High-technology industry is not labor-intensive work thanks to the efficient robots used. On the opposite side are smoke-stack industries, that we presume include the older, basic industries such as mining, agriculture, iron and steel manufacturing, ship-building, auto manufacturing, and nearly all forms of construction. These industries are judged to be labor intensive, requiring unsophisticated and untrained employees who succeed by the sweat of their brows rather than by advanced degrees in mathematics and physics. If these are indeed the presumptions about high technology versus smokestack industries, then I submit that those presumptions are a disaster. They are wrong and far from the truth. Smokestack industries, such as mining and the others mentioned, are indeed much older than some of the recently founded high-tech industries. But this does not mean that those smokestack industries are low-technology industries. On the contrary, American agricul¬ture is a very high-technology industry whose crop yields are the envy of the entire world. Mining uses virtually all of the advances available through modern technology. Far too many opinion leaders still envision mining as Humphrey Bogart and John Huston in the movie Treasure of the Sierra Madre. Yet there are many who hold the opinion that our basic industries are dead and that this country's future depends on specialized high-technology industries and services. That is tantamount to announcing we will continue to build space shuttle vehicles, but we no longer need launching pads and landing fields. The point is, we should not be wasting our time talking about "new" industries and "old" industries. We should devote our time and effort to industries that are effective and efficient in meeting our needs, in contrast to industries that are not effective and efficient in meeting our needs. Less Developed Countries That leads me to some of the problems I perceive with policies regarding the previously mentioned LDCs - Less Developed Countries. Far too many people do not realize that many of the smokestack industries being lauded in Less Developed Countries are being operated at a loss and to the detriment of worldwide industry. And the losses incurred

Jan 12, 1983

By Christoph Mueller, Grzegorz Tabak

Basing on five years of experience, this paper discusses modern e-drive systems used in underground transport. This covers Energy distribution and cabling principles, inverters and motors as well as auxiliary aggregates. Also an overview of different regimes for battery charging and the energy management and the method of control of the traction are lined out: This means that throttle and brake are not handled separately, but integrated into “longitudinal control” algorithms which assure that a commanded speed is maintained while synchronizing the multi motor systems and taking into account the constraints imposed by e.g. slope grade and battery parameters.

Jun 25, 2023

By Michael Kukay, Paul Conrad, Cosmas Opoku-Ware

This project is exploring the potential for developing trees tolerable to degraded un-reclaimed mine site soils and tailings as a solution to re-establishing long-term tree growth on those sites. The project incorporates growing tree seedlings in an underground greenhouse grown from seeds planted in the degraded mine soils in which they will eventually be planted. The outcome of the project is expected to lead to a successful solution for re-establishing tree growth in soils and tailings containing high metal concentrations with minimal post-planting human intervention. The research is being conducted in an underground greenhouse located 100 ft below the surface in the old Orphan Boy Mine Underground Mine Education Center (UMEC) located on Montana Tech’s campus in Butte, Montana.

By Frederick McNeill, Mahmood Khwaja, Benjamin Lundsted, David Polcari, Michael S. Schultz, Timothy Clougherty

The City of Manchester, New Hampshire, is embarking on one of its largest public works projects in history to construct a 12,000 foot long, large-diameter, conveyance tunnel through downtown Manchester. This area has challenging geology with undulating bedrock (granite, schist, and gneiss) profile overlain by fluvial deposits. Understanding the subsurface conditions is key to mitigating project risks, establishing plan and profile for the tunnel, and selecting the most cost-sensitive and technically appropriate tunneling method. This paper presents the project team’s approach for conducting the ground investigation, developing preliminary subsurface profile, and the considerations for selecting the tunneling method.

Jun 13, 2023

By Fangyu Liu

In the grand tapestry of scientific inquiry, there are individuals whose contributions resonate far beyond the confines of laboratories and lecture halls. It is with profound admiration and respect that we present this special collection of Mining, Metallurgy & Exploration, dedicated to celebrating the remarkable career of Dr. Patrick Taylor. Dr. Taylor, recently retired from the Colorado School of Mines as the Emeritus Ansell Distinguished Professor of Chemical Engineering, possesses over 45 years of expertise in mineral processing and extractive metallurgy. His remarkable journey has seen him traversing the globe, from Canada to Egypt, contributing to pyrometallurgy, hydrometallurgy, and mineral processing. Dr. Taylor’s portfolio encompasses lab work, pilot-plant projects, research, and process development across various metals, with an impressive array of authored papers, presentations, and nine patents to his name. A soughtafter consultant for over 20 companies and an esteemed expert witness, Dr. Taylor also led the Kroll Institute for Extractive Metallurgy at Colorado School of Mines. Under his guidance, more than 100 graduate students and post-docs have undertaken transformative research, while Dr. Taylor’s 45-year tenure as a university lecturer and the creation of 10 industryfocused short courses underscore his dedication to knowledge dissemination. His contributions extend to crafting professional engineering exam questions for a quarter-century and active participation in esteemed organizations like SME, TMS, ASM, and MMSA.

Sep 16, 2023

By NILAMADHABA SAHU, Gajanan U. Kapure, Pankaj Kumar, Sunil Kumar Tripathy

Chromite ore processing tailings and low-grade manganese ores are typically considered waste due to their limited or negligible utility, leading to environmental and storage concerns. Researchers globally have explored various methods to utilize or upgrade these wastes, particularly because dumping chromite ore has been linked to severe health issues through Cr(VI) leaching. Individually, these ores lack economic value, and there has not been research on simultaneously reducing both low-grade ores. In this study, the focus lies on smelting these ores together, aiming to create a precursor alloy for 200 series stainless steel scrap. Initial research indicates the potential for scrap formation, validated through laboratory experiments with varying coke rate, basicity and holding time. The investigation discovered that smelting this combination could yield a metal product consisting of 59 percent Fe, 24.93 percent Cr, 7.56 percent Mn, 0.62 percent Ni and 0.93 percent Si. The optimum basicity was found to be 0.6 with 80 percent recovery. Notably, this process eliminates intermediate steps in 200 series stainless steel production, potentially reducing overall carbon dioxide emissions. This proposed method represents a cleaner, sustainable approach to repurpose these two waste ores, projecting a net profit of US$330/t.

May 1, 2024

By M. Kavvadas

Geotechnical design using Factors of Safety recommended by Codes of Practice is based on largely unknown ?margins of safety?, usually without consideration for the importance of the project (i.e., potential consequences of failure) directly or explicitly. On the contrary, probabilistic modelling can be a useful tool in risk management as it provides the means to measure the risk to be managed. This is achieved by calculating the probability of failure associated with a specific design, i.e., by relating the classical factors of safety with the corresponding probability of failure and by using a cost optimization procedure to achieve ?optimal? designs, accounting for the expected costs in case of catastrophic failure. This paper describes the methods used to calculate the probability of failure and its correlation with the classical Factor of Safety using sampling techniques and a simplified method based on the moments of the factor of safety considered as a random variable. These procedures are illustrated in an example which investigates the stability of a slope.

Jan 1, 2005

By T. Faulkner, S. A. Richards

"The Scale-Distance formula is one of the primary means of determining the maximum amount of explosives that can be safely detonated at one time by a single delay. This paper describes a method of applying the Scale-Distance formula to the entire mining area using gridded surfaces. Using this technique, the operator can better determine the economic impact of nearby structures on the mine plan. INTRODUCTION As the surface mining of coal and stone encroaches near populated areas, precautions must be taken to minimize blast vibration damage to protected structures. The common method employed to minimize vibration damage is not to reduce the total amount of explosive in the hole (which would negatively affect fragmentation), but rather to introduce delays to reduce the amount of explosive detonated at any point in time. The Scale-Distance formula, an industry-accepted standard, may be used to calculate the maximum weight of explosive that can be detonated at one time without damaging the structure. This information may then be used to determine the number of delays required for each hole. Detonators make up a large part of the cost of blasting. At roughly $15 per detonator an additional detonator in the hole can be significant. It is normal to set off hundreds of holes at in one shot. An additional detonator in each hole can cost additional thousands of dollars per shot. The number of detonators is also a function of the depth of the holes and the hole spacing. Being able to accurately forecast the economic impact of blasting near structures improves a company’s ability to make informed decisions on how to approach property owners. Operators basically have three options when dealing with property owners: 1. Buy the property and blast without restriction 2. Negotiate with property owner for a waiver to allow unrestricted blasting 3. Comply with the legal blasting restrictions This paper proposes a method for the engineer to forecast for all points in the proposed mining area the impact of nearby structures upon the blast design. Being able to create a contour map and ultimately estimate the number of delays required for the entire forecasted mining area, the engineer can create accurate economic forecasts of the cost of blasting. The objective is to reduce the level of uncertainty in the forecast of the blast component portion of the forecast."

Jan 1, 2016

By Jörg Holzhäuser, Matthew Crow

An 18.5 km (12 mile) long tunnel is being driven by four Earth Pressure Balance Tunnel Boring Machines (EPB-TBMs) of 4.7 m (15.5 ft.) diameter through alluvial sand, gravel, silt and clay above and below the groundwater table in Los Angeles beneath buildings, railroads, freeways and the L.A. River. Continuous automatic data recording of TBM operation and field inspectors' records, accompanied by monitoring of 5,000 surface reference points and 268 borehole extensometers were used to obtain information. The paper explains the reason for selecting the method of EPB-tunneling to ensure stability of the tunnel and meeting of environmental requirements, and presents data collected to monitor and demonstrate the performance of the TBM sin the different ground conditions encountered.

Jan 1, 2003