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By A. H. Balch

A physical elastic seismic model, based on the Peoria oil field was constructed and used to produce multi mode cross-borehole seismic data. Because this was a physical model, it was necessary to deal with a complex wave field consisting of compressional waves, shear waves, and converted waves. The recorded raw data were complex, have no resemblance to the inter-well geology, and were difficult or impossible to interpret. These unintelligible data sets were extensively computer processed. Detailed, accurate, images of the inter-well structure, and reflecting horizons were obtained as a result of this processing. This investigation demonstrates that excellent, accurate images of the inter-well geology can be obtained by skilled seismic cross-well data acquisition and extensive careful computer processing.

Jan 1, 1993

By D. D. Eyer

New or improved technology will continue to drive productivity improvements through the next decade. In January 1988, I presented a paper titled, "Large Underground Mines of the 1990s? before the SME. I will follow some of the themes developed in that paper as modified by our experience in the past two years. In order for a coal company to be profitable today, it has had to reduce unit costs experienced in the past. This is because the current average realization, even accounting for a recent strengthening, remains below that of a few years ago. Doing business as was done in the past is not good enough. The coal industry needs to increase productivity in the range of 5-10% annually merely to stay even with rising costs. Underground productivity has been increasing more rapidly than that for surface mining. With the exception of the Powder River basin of Montana and Wyoming, underground productivity has caught up with that for surface mining in many regions of America. There are a number of technological factors which have attributed to increases in underground productivity and which should be factors in the future.

Jan 1, 1990

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jonathan K. Hrica, CASSANDRA L. HOEBBEL, Jason Navoyski, Jennica L. Bellanca

The paper describes the process of collecting detailed accounts of near-miss incidents and turning them into impactful visual stories using graphic simulation. The aim is to create high-quality training materials to reduce haul-truck-related accidents and fatalities in mining.

Sep 1, 2023

By Ankit Jha, Javad Sattarvand, Aaron Young

Blockchain technology is one of the prominent disruptive technologies that are being implemented in several disciplines. The application of blockchains in the mining and mineral industry can provide utility to several processes especially when the industry is undertaking digital transformation. The governing principles of blockchain technology are applicable in undertaking transformation in several processes within the mining industry. This study investigates the applications of blockchain technology within the realms of the mining industry and identifies key areas of implementation. A systematic review of publications on academic platforms relating to blockchain technology in the mining industry did not retrieve a considerable number of articles. Consequently, a thorough review of white papers and articles authored by individuals on use cases within the mining industry is compiled and presented in this review article. This review article identifies all the potential areas within the mining industry where blockchains could provide value and improve processes through their implementation. The broad area of implementation of blockchains includes supply chain, traceability in spares parts, contract management, regulatory compliance and cybersecurity.

Mar 1, 2024

By J. Gauntt

Calcium carbonate is one of the most widely used industrial minerals in applications like cement, lime, agriculture, power plant fluegas desulfurization (FGD) and construction aggregates. Most applications are generally high-volume and low value ($9/t or $10/st) or less free-on-board (f.o.b.) mine site) uses of this material. Specialty uses of ground calcium carbonate (GCC) are typically referred to as ?performance mineral? or ?extender and ?ller? applications. Primary specialty markets for GCC include paper and plastics as well as a number of construction applications including joint compounds, carpet backing, paint, and adhesives, caulks and sealants (ACS). Other important specialty applications for GCC include rubber, food and personal care products. A new and growing application for GCC is in nonwoven fabrics, where this mineral replaces a small percentage of the polymer. Typical specialty applications for GCC are color sensitive and require extremely white/bright materials. Although deposits of limestone are located in most states, high brightness resources are relatively rare and controlled by a limited group of suppliers.

By G. A. Perry

Cyprus Sierrita is a major producer of copper and molybdnum from its Sierrita and Twin Buttes open pit mines south of Tucson, Arizona. Both pits were started in the late 60's and are in excess of 1500 feet in depth. Sierrita has utilized a Cat 992C Remote Controlled Loader since January 1993. The loader was justified to increase SAFETY and PROFITS at Sierrita. It has exceeded all expectations. As of June 1993, it had produced additional profits totaling more than $1,500,000.

Jan 1, 1994

Despite two large projects represented in the keynote docket, the mood of the 2011 SME Arizona Conference was summed up best by Ferol Baker, general manager of New Mexico Copper Corp. (a wholly owned subsidiary of Themac Resources Group), ?In the past, it seemed like you couldn?t go to a conference like this without hearing about one big new greenfield project after another. Now what you see is companies doing internal expansion or small-scale brownfield development.? Overall, the tone of this year?s meeting, held at the J.W. Marriott Resort at Starr Pass in Tucson, AZ, was upbeat, yet practical. From the keynote and luncheon addresses to the six panels of sessions, the projects described were positive about the future, yet focused on the details required to make those projects come to fruition.

Jan 1, 2012

In the late 1980s and into the 1990s, the Mountain Pass Mine in California produced about 40 percent of the world?s rare earth elements. At the height of this production, the facility produced up to 54 L/s (850 gpm) of saltwater that was piped to offshore holding ponds where the water was evaporated. In 1998, following a series of waste water pipeline breaches, separations activities were suspended, reducing the Mountain Pass site to just the openpit mine and mill. The environmental concerns were addressed and the affected areas have since been remediated. However, in the years following the breaches, 97 percent of the world?s production of rare earth elements moved to China. By 2011, Molycorp, and the Mountain Pass Mine, had rebounded from the difficult times and were once again in a position to become a significant player in the rare earth industry.

Jan 1, 2011

By G. Pierson

Explanations of commodity price levels, or movements, commonly focus on the supply and demand fundamentals of the particular commodity, or else are assigned to speculative activity. Comparisons of metal price histories with monetary and other economic data support the argument that the supply of and demand for money are no less important in price determination than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1996

By Todd Minoski, KRISTIN FLOYD, Michael Murphy, VASU GANGRADE, Gamal Rashed, DYKE MARK VAN, Brent Slaker

Underground stone mines frequently operate on multiple mining horizons or are required to undermine or overmine old workings. In these situations, the effects of pillar columnization and interburden thickness on the stresses surrounding mine workings are poorly understood. Many old workings were not designed to consider the effect on future undermining or overmining and, as a result, are laid out on irregular patterns and with pillar sizes that are difficult or impossible to replicate on adjacent levels. Additionally, as depth increases, even a consistent gridded mine layout may result in poor columnization due to the need to increase pillar sizes. Rules of thumb and past practice for designing multiple levels may often be effective. This paper explores the effect that multiple-level stone mining has on stress redistribution through the discussion of two case-study mines and associated numerical modeling to provide additional insight into situations which may cause concern.

By K. Sample

Slope stability analysis plays an integral role in the design of various mining applications including waste dumps, heap leach piles, solution ponds, and tailings dams. Generally, limit equilibrium analysis using one of the several prevalent approaches is considered adequate. The density, saturation, and shear strength parameters of the materials forming the slope affect the failure mode and the calculated factor of safety (FS) against sliding. These parameters are generally based on laboratory tests. Field practices and construction procedures are often not completely simulated in the laboratory for various reasons (e.g. equipment limits, time and budget restraints, etc.). This paper presents a holistic assessment of slope stability analysis as practiced in mining applications, using example data from multiple heap leach projects. A sensitivity analysis is presented for variations in material properties, data interpretation, and computation methods. For each step in the design process, the possible variations in parameter values were identified and then used to perform traditional and probabilistic stability analyses. This simple, cradle-to-grave-type approach is used to evaluate the reliability of an example design, and the combined impact of multiple uncertainties on the factor of safety. Example Study The issue of addressing uncertainty in geotechnical design has been discussed in depth by numerous authors (Duncan 2000; Christian 2004; Whitman 1984; Christian et al. 1993). One may ignore the uncertainties involved in a design, take a conservative approach, rely on observational methods (Peck 1969), or attempt to quantify the uncertainty. Geotechnical projects in general, may include a combination of these methods. For important structures, such as heap leach pads, it is critical that sources of uncertainty in the stability analysis be acknowledged early on and considered in the overall design approach. As with any project, economics and other physical constraints, such as space limitation, often do not always allow for an overly-conservative, robust design. In an effort to quantify uncertainty and provide a sense of level of confidence in the safety and reliability of a design, probabilistic methods have been developed and implemented in many slope stability software packages. Reliability methods are often used in the design of open pit mine slopes, but not as commonly in designing heap leach pads and waste dumps. As an example, the stability analysis of a copper heap leach project is presented here to evaluate the effects of multiple sources of uncertainty and differing methods of data interpretation. Some of the parametric values, or the variation therein, are assumed on the basis of actual data from multiple heap leach projects, included in the paper as well. A generic representation of the example case study is shown in Figure 1. As depicted in the cross-section, the ultimate height of the design is 114 m (measured from the crest to the toe). The overall slope of the heap leach pad is 1.88 horizontal to 1 vertical (1.88H:1V), or 28°. The slope benches are considered in the overall slope. The example leach pad is founded on alluvial, colluvial and residual soils overlying weathered limestone. The ore to be placed on the pad is characterized as poorly graded gravel (GP) with average fines content (percent passing #200 sieve) of 4%. The liner subgrade is low permeability (fine) soil. The cover or the drainage material, placed directly above the geomembrane (between the liner and the ore), is crushed ore in this case. The phreatic surface was assumed to be 1 m above the base liner, which is what the collection system over the liner is typically designed for. [ ] In heap leach pads, typically, Linear Low Density Polyethylene (LLDPE) or High Density Polyethylene (HDPE) is used as the base liner. The decision is based on the elongation, strength and other requirements of the application as well as economic considerations. In this example study, the base liner was 80-mil single-side textured LLDPE. FIELD INVETIGATION AND SAMPLING When selecting appropriate values for the input parameters of the stability analysis, the level of uncertainty in the data and the assumptions that are made must be clearly identified and considered in the design. This concept has been emphasized through an extensive number of publications regarding geotechnical uncertainty and reliability (Christian et al. 1994; Duncan 2000; Christian 2004). The primary source of uncertainties involved in slope stability analysis for mining applications is inadequate geotechnical investigation, often lacking in a thorough assessment of in-situ material characterization and sampling disturbances. To emphasize this point, some background information is presented here. The tradeoff between the costs of a thorough site investigation versus the risks of design uncertainty has long been a challenging management decision in geotechnical projects. For mine sites, significant investment is typically made in exploration and estimating mineral resources and the geology of a mine site is often more thoroughly documented than other types of geotechnical projects. Nevertheless, the engineering properties of the soil and rocks relevant to slope stability receive less emphasis. Baecher and Christian (2003) observed that the areas of geotechnical concern, such as slopes and waste disposal facilities, are usually associated with mine costs rather than revenue, and therefore, significantly less money is devoted to their site characterization and laboratory testing. The expenditure for site investigations varies significantly from project to project, with higher levels of uncertainty and, therefore, the

Jan 1, 2009

By W. Linwood Haden

Fullers earth has been mined since about 1920 in southwest Georgia and the adjoining area of Florida. In 1935, the mineral was named "attapulgite" after the source of a sample near the town of Attapulgus, Decatur County, Georgia. Mining and processing of the clay was described in a 1930 publication1 at a time when petroleum refiners were the major users. In the years since then, the uses and users of attapulgite have multiplied, and both mining methods and processing methods have been changed to optimize the clay for the new uses. A comprehensive review of the properties and applications of attapulgite 2 has been published. Only a brief review will be given here to explain the properties being sought and to show how these properties are optimized by mining and processing practices.

Jan 1, 1972

"Replacing the century old rail tunnels that run beneath the Hudson River and carry about 200,000 passengers per day between New York to New Jersey has been a high priority for many years. But after Superstorm Sandy hit the east coast of the United States in 2012, the urgency to replace the tunnels increased dramatically. The Hudson Tunnels project is one of nine projects that make up the larger $30 billion Gateway Project. The Gateway Project has been called the most urgent infrastructure program in the country and the Hudson Tunnels is the most critical part of the project, as it will build a new rail tunnel under the Hudson River and rebuild the existing and deteriorating North River Tunnel that connects New York and New Jersey.“Superstorm Sandy proved the level of resiliency of the tunnels, which was not very good,” Amtrak deputy chief engineer structures James Richter told attendees of the George A. Fox Conference in New York City on Jan. 23. Age and corrosive salts deposited by flood waters from the storm in 2012 have affected interior concrete and copper wiring in the tunnels. “Since then, things have been deteriorating and getting less reliable.”Richter, along with Mohammed Nasim, senior director engineering design, both with Amtrak, spoke at the 2018 George A. Fox Conference where more than 350 tunneling and underground construction professionals attended the conference at the Graduate Center of the City University if New York to share insights about the complexities many of them face on daily basis.Under the theme of “Managing construction of complex underground projects: Strategies for tunneling in populated areas,” the one-day conference featured presentations from some of the top minds in the tunneling and underground construction industry. The presentations touched on everything from the highly technical challenges of constructing tunnels through changing geology while working beneath cities and rivers, to navigating the complex financial issues and contracts that come with the projects that have many stakeholders.All of those challenges, and more are part of the Hudson Tunnels project. It is one of the best examples of the full complexities of a complex tunnel project, with the added pressure of securing funding from state and federal government entities under an increasingly tight deadline."

Jan 3, 2018

"When boring a tunnel, homogeneous hard rock is the exception rather than the rule. While contractors can set goals such as meters per month and performance incentives, it is also prudent to plan for difficult ground. A properly designed tunnel boring machine (TBM) can tackle fault zones, water inflows, squeezing ground, or whatever the risk may be. The alternative is not a good one: modifying the machine in the tunnel after bad ground is encountered. Not only does this result in increased downtime, but it also needlessly exposes the crew to the tunnel conditions. In the worst case scenario, the entire operation grinds to a halt.However, an accurate GBR cannot always be obtained, particularly for mountainous, high cover tunnels in remote locations. And even with a thorough GBR, unforeseen geological events can occur. What can be done in these situations? Difficult Ground Solutions (DGS) is ground investigation system with a suite of options that can be added to a shielded hard rock machine or dual-mode, Crossover machine to better enable advance when conditions are unknown or difficult conditions are anticipated.DGS consists of a set of integrated features tailored to a specific project’s geology. The main components of the system allow for ground investigation ahead of the TBM, increased monitoring and methods to keep a machine shield from becoming stuck.In fault zones and squeezing groundIf fault zones or squeezing ground are known or suspected, or if there is even a possibility of encountering them, this can greatly affect the TBM operation. Shielded machines protect the crew from the surrounding rock, and they can bore and line a tunnel efficiently, but in fault zones and converging material their shields can be their downfall. Avoiding a stuck machine is paramount to project success. DGS employs several features to avoid the problem of a machine becoming stuck. The first of these is multi-speed cutterhead drives. These drives effectively give the machine multiple modes of operation—high speed, low torque for hard rock, and low speed, high torque for difficult ground. Designing a machine with high-torque, continuous boring capabilities allows that machine’s cutterhead to restart with break-out torque in difficult ground. The net effect is that the machine can keep boring in the event of a face collapse and can bore through fault zones and running ground where the potential for cutterhead jamming exists. Going one step further, multi-speed gearboxes give the machine the ideal earth pressure balance- (EPB-) type torque if larger sections of soft ground are anticipated.Secondly, TBMs can get through squeezing ground and faults using Continuous Shield Advance. This design utilizes a stepped shield configuration — where each successive shield is slightly smaller in diameter — to avoid becoming stuck in converging ground. External shield lubrication is an added insurance against becoming stuck, using a series of radial ports that can pump Bentonite into the annular space to act as a lubricant in squeezing material.As a last effort, if a machine has already become stuck the TBM can utilize augmented, or “super” thrust. Additional thrust jacks can be added to supply an extra boost in a short stroke, generating enough force to break loose a trapped shield."

Jan 12, 2017

By F. D. Wang

This paper presents an innovative mining method with the application of the water jet. The basic principle of this mining method is to mine a thin panel slice with a water jet system and to allow the roof to deflect elastically and subsequently to be supported by the coal floor without artificial roof support. Through the sequential mining of layers from top to bottom, the entire seam is extracted and the roof rests upon the mine floor. The advantages of this method are that the safety of underground operation can be greatly increased and the surface overburden disturbance will be markedly reduced. . An economic evaluation of such a system is presented for the total cost estimated per ton of coal mined at the face. This evaluation is then compared to that of a continuous mining section utilizing a room and pillar mining method.

Jan 1, 1991

By Greg Beckstrom

On Oct. 1-3, SME?s Twin Cities chapter (SME TC), in cooperation with the University of Minnesota ? Duluth?s Precambrian Research Center (UMD-PRC), cohosted a symposium on silica sand mining and processing. The conference was held at the Earle Brown Heritage Center near Minneapolis. The symposium was followed by a day-long field trip to operating mines, processing plants and loading facilities located in southwestern Wisconsin. Speakers and attendees at the symposium included university professors, industry experts, regulators, mining company representatives, equipment suppliers, consulting engineers and service companies. Approximately 320 people attended the conference. In addition, about 50 people who oppose mine development and the oil and gas industry showed up to voice their displeasure with the event and those companies that operate in this space.

Jan 1, 2012

By J. W. Leonard

Gravity based coal/mineral preparation plants must be operated to yield products of a quality satisfactory to existing markets; but, because of historic control problems, recovery is frequently sacrificed to achieve quality resulting in losses of valuable product. Plant control has ranged from intuitive in-plant spot quality judgments made by various operators to gross methods involving such devices as density gauges, floats, grab-sample on-the-spot sink-float tests, etc. Millions of tons of quality coal/minerals are lost to refuse each year, because of the historic lack of a continuous and dependable control system. The result is both serious economic as well as environmental losses. While the economic losses are obvious, less obvious environmental losses, in the case of coal, result from the misplacement of more ignitable quality fuel to refuse banks. A control system capable of supplying a market-grade coal/mineral product, while continuously minimizing product losses to refuse, has until recently escaped technology.

Jan 1, 1991

By John Hickey

Management teams at mining companies begin to ask themselves whether to take a company public and, if so, how to do it as they approach the normal threshold for going public in terms of revenue and operating performance. Today, the expense of going public generally suggests the company has at least $20 million in annual revenue and at least $2 million in cash. The revenue number can be lower for mining companies with large reserves. In order to properly attract the investing public, the company must also be operationally strong with robust prospects. The company should have a strong management team and a consistent history of double-digit growth that will continue into the foreseeable future. Assuming the thresholds are met, a company?s management needs to weigh the pros and cons of going public.

Jan 1, 2012

It is widely accepted that particles stabilize flotation froths and that stable froths result in improved flotation performance. Predicting the effect of particle addition on froth stability is, however, challenging. Furthermore, there is currently no technique that allows the prediction of the effect of different flotation reagents on froth stability, without carrying out froth stability experiments.

Overland conveyor belts that exhibit tracking problems under loaded and unloaded conditions can be tested to' determine the root cause of the mistracking. Moveable conveyors are more prone to mistracking due to structure alignment requirements. In addition, belting quality, splice straightness and carcass condition has a dramatic effect on the performance of a belt in relation to tracking. Methods are discussed that are proven to reduce belt mistracking and improve the operational reliability of the conveyor system.

Jan 1, 1995