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By T. Veneroso

Comminution is the process by which rock or ore is reduced to a size where the liberation of the minerals is maximized without changing the chemical or physical properties of the rock. Comminution accounts for about 50% of all energy that mines use (Klein et al., 2018). Growing demands from stakeholders and shareholders for sustainable development and CO2 reduction will increase the need for energy-efficient comminution. Ores with different mineralogical characteristics, textures, strengths, apparent stiffness, and mass-specific fracture energies need to be processed with a specific, new, and efficient comminution technology to increase the production and profitability of mining companies. The adoption of crusher wear parts built with new materials, such as non-Hadfield manganese steel or synthetic materials or traditional manganese with wear-resistant components, could improve the efficiency of the crushers, reduce downtime, increase production, improve the desired P80 (the aperture through which 80% of the product will pass) product size distribution, and enhance mine safety.

Feb 1, 2023

By David Chastka, Isidro Rivera, Shawna Von Stockhausen, Idit Zarchi

The City of Santa Cruz Water Department is replacing the existing Newell Creek Dam inlet/outlet works at Loch Lomond Reservoir in the San Lorenzo Valley. The project will improve the City’s overall operational efficiency, improve system performance, and improve the safety and reliability of storage for the City’s drinking water supply. The project comprises new inlet works* (three new inlets that control and convey flows into and out of the reservoir, and an intake control building), an inlet/outlet tunnel with a 48-inch conduit to convey flows into and out of the reservoir, and a new outlet structure at the toe of the dam. The outlet structure includes a release point for energy dissipation of emergency drawdown flows, a connection to Newell Creek Pipeline, and beneficial releases into Newell Creek. The project also includes a new dam seepage collection and monitoring system and appurtenant structures such as a culvert bridge over the spillway plunge pool to improve access to the new outlet. Notable complex project components include in-water work to connect the new intake shaft pipes to the three new inlets. The project includes one major milestone with a work window regulated by environmental permits that could only be amended/ extended with approvals from those agencies. If not met, the milestone work would have caused significant delays (potentially up to one year) to the project.

Jun 13, 2021

Caterpillar unveiled a new dozer, the new Cat D10T2 dozer, that builds on the success the company has had with its D10T model. The newest version of the dozer includes refinements to its power train, automated controls and structures. The result, the company said, is high productivity with superior fuel efficiency, reliable operation with long-lived structures, as well as enhanced access for service technicians and operators. The D10T2 uses the latest load-sensing hydraulics technology combined with Cat advanced engine controls to maximize the amount of material moved for every drop of fuel burned. Improved filtration protects the fuel system, hydraulic system and power train oil system to help ensure high reliability and minimal machine downtime. Refined large structures, such as redesigned track roller frames, deliver longer service before rebuilds. Improved access and egress features enhance safety and productivity of technicians and operators, and optional powered access systems and platforms enable configuring the D10T2 for the site. Caterpillar offers the D10T2 with two variations of the Cat C27 engine with ACERT Technology. One version is U.S. Environmental Protection Agency (EPA) Tier 4 Final certified, and the other is capable of achieving emission levels equivalent to EPA Tier 2 standards. Both engine configurations produce net power of 447 kW (600 hp) in forward gears and 538 kW (722 hp) in reverse gears. The engine controller automatically adjusts power output based on the direction of travel. With the new system, the D10T2 has about 20 percent more power in reverse compared to its predecessor model. The result is faster cycle times and greater productivity in certain applications. The D10T2 is suited for a variety of applications including mining, heavy construction and bulk materials handling.

Mar 1, 2014

By G. L. Mowrey

In addition to developing various types of coal interface detection systems, the U.S. Bureau of Mines is actively involved in developing a coal rib thickness monitoring system for high wall mining applications. One particular system that appears to show promise uses a ground-penetrating radar system to detect the coal-air boundaries of coal ribs. Based on preliminary laboratory and field tests, results indicate that this method can be applied successfully in highwall mines to maintain a constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

Jan 1, 1995

By R. L. Virta

Sixteen companies mined fuller’s earth in 11 states during 2004. Production during 2004, based on a preliminary survey of fuller’s earth producers, was 3.96 Mt (4.3million st) valued at $340 million. This compared with3.6 Mt (3.9 million st) during 2003, valued at $346 million. The 3.96 Mt (4.3 million st) probably includes some crude clay tonnage. And production of finished product probably was closer to 3.2 Mt (3.5 million st) in 2004. Georgia was the leading producer state of attapulgite-type fuller’s earth, followed by Florida. Georgia also was the leading producer state for montmorillonite-type fuller’s earth. It was followed, in descending order, by Mississippi, Missouri, Florida, Virginia, Illinois, California, Tennessee, Kansas and Texas.

Jan 1, 2005

By W. Z. Rogers

U.S. feldspar output sold or used in 2004 was estimated to be 790 kt (871,000 st), valued at $43 million free-on-board plant. This was below 2003 and about the same volume as 2002. The strong housing market in the United States maintained demand for ceramic tiles, plumbing fixtures, and fiberglass insulation requiring feldspar and shipments of glass containers increased by about 4 percent. Imports of ceramic tiles and plumbing fixtures continue to increase, taking the place of U.S. produced goods, and the feldspar required to make them. Output included flotation concentrates, feldspar content in feldspar-silica mixtures, potash feldspar and aplite.

Jan 1, 2005

By Todd Burchett

Mining engineers spend countless hours and resources when designing a new underground coal mine. Their primary objective is to design the safest and most efficient operating mine with regards to coal production. A key variable often overlooked in this design stage is the slope conveyor. Typically, a slope conveyor is expected to operate with a 98-percent or higher availability. However, too often little effort is put forth by the mining engineer to optimize its design. Coal companies will rely on engineering, procurement, construction and management (EPCM) companies for the preliminary design, because the slope conveyor will be considered part of the surface material handling processes. This preliminary design will be used when soliciting quotations for the slope conveyor. Unfortunately, EPCMs may not have enough expertise with conveyors to optimize the design. This expertise is available with an original equipment manufacture (OEM) of conveyors, which ultimately may be responsible for supplying the slope conveyor. Each OEM will provide a bid package that represents what it considers to be the optimal design.

Jan 1, 2013

The 29th annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Star Pass Resort, Tucson, AZ on Saturday, Dec. 3, 2011. Each year, one living inductee, two recipients of Medals of Merit, and up to five honorees from mining history are chosen by the MFSW for their outstanding contributions to the mining industry. Chilean Minister of Public Works and former Minister of Mining, Laurence Golborne Riveros will be the guest of honor, featured speaker and inductee into the American Mining Hall of Fame. Golborne Riveros was instrumental in managing the rescue of the 33 Chilean miners in October 2010 and in the coordination/management of the ?townsite? for family members, rescue support and the media. His engineering background and executive management skills made him ideally suited to assist in both a technical and managerial role in this emergency.

Jan 1, 2011

By Dan Plazak

The authors are to be congratulated for presenting a simple and practical tool for quick estimates of ground water flow rates. At the risk of detracting from the simplicity of the method, I would like to suggest a slight refinement to the equation as presented. As the authors noted, the Jacob-Lohman equation (1952) assumes confined-aquifer conditions. To use confined-aquifer equations in water-table aquifers, Jacob (1963) presented a correction to convert water-table aquifer drawdowns [ ] to equivalent confinedaquifer drawdowns [ ]:

Jan 1, 1994

By Eti Purwaningsih, Widi Astuti, Erik Prasetyo

Increasing demand for high-grade manganese (Mn) ore has led to the practice of selective mining, which produced low-grade Mn ore as waste and in the long term could lead to environmental pollution. Research had been carried out to extract Mn from low-grade ore, which mostly exists as black Mn(IV) oxide (MnO2). Most extraction methods involved the reduction of insoluble MnO2 to soluble Mn2+ in acidic media. Metals other than Mn are also transferred to the pregnant leach solution (PLS) during the leaching process, especially iron (Fe). Due to high Mn concentration in PLS, precipitation is considered the best method to isolate Mn from PLS compared with solvent extraction and ion exchange/absorption. However, due to unselective leaching, the presence of Fe in the PLS makes the Mn separation and purification difficult. Therefore, in this research, the parameters affecting the selectivity of Mn over Fe in leaching process were investigated.

By D. A. King

Monitoring devices have been installed at several mine sites to assess the potential for the development of acid rock drainage (ARD) in waste rock, spent ore, and tailings material. In addition, instrumentation has been designed for monitoring changes in water quality in pit lakes. These devices monitor temperature, oxygen, water movement, and water chemistry in the waste rock pile. This information can be used to evaluate the current and future ARD risk, the effectiveness of caps and covers, and provide information to aid in the design of other reclamation strategies that limit ARD development. The instrumentation includes nested thermistors and oxygen sensing ports, neutron access tubes, heat dissipation units (HDUs), and lysimeters. Many of the monitoring devices can be linked to a datalogger and telemetry systems, enabling monitoring data to be downloaded from the office.

Jan 1, 1997

By R. J. Pugh

The surface chemical sites on several fillers (quartz, feldspar, calcite and granite) were studied by the adsorption of well defined acid and basic probe molecules (benzoic acid, benzyl alcohol, ethyl benzoate, pyridine and benzyl amine) from cyclohexane. The results provided a wide variation of adsorption data, emphasizing the extensive range of site heterogeneity on the filler surfaces. In addition, it was shown that the acidic probes were strongly adsorbed on all of the minerals, thus indicating that the basic surface sites dominate the acidic ones. Also, through FTIR studies with vapor-phase probes adsorbed on orthoclase, it was possible to identify the nature of specific sites and the type of bonding occurring between the filler surface and the probe molecule. These types of surface analytical techniques could give useful information for predicting the adsorption functional groups on dispersants, dyes, thickeners, etc. and could lead to enhanced interfacial bonding between the filler and the matrix.

Jan 1, 1993

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine or the expansion of an existing mine can range from nine to 24 months, or even longer. The time frame will vary depending on whether an environmental assessment (EA) or an environmental impact statement (EIS) will be completed Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. In this paper, a two-year natural resource baseline study by Homestake Mining for the Ruby Hill Mine, Eureka County, NV, is used as a case study to describe how a properly designed and executed natural resource baseline study streamlined the NEPA process.

Jan 1, 2003

By V. Rajaram

R.C. Rex, Jr. V. Rajaram's paper does not accurately reflect the status of Eastern oil shale development as it stands today. Today, there are numerous firms and research organizations pursuing development of the Eastern oil shale resource. Details of the current projects can be found in the symposium proceedings for the 1985 Eastern Oil Shale Symposium held in Lexington, KY, in November 1985. Additionally, the comparison of the Paraho and HYTORT processes is invalid because the HYTORT process design used it not an accurate representation of the HYTORT process. I will briefly address this point. It is disconcerting to see the author reference hydroretorting work conducted at the Institute of Gas Technology (IGT) (circa 1978) in the introduction, which indicates hydroretorting (the HYTORT process concept) yields of up to 250% of the Fischer Assay oil yield, and then turn around and base the remainder of the paper on the 1981 "Synthetic Fuels From Eastern Oil Shale Report," which depicts the HYTORT process as yielding only 115% of Fischer Assay. Indeed, work conducted at IGT to 1981 indicates commercial oil yields for the HYTORT process would be in the range of 200% to 210% of Fischer Assay. A more thorough literature search by the author would have yielded a 1981 publication by Schora et al., entitled "Update on the HYTORT Process" presented at the Symposium on Synthetic Fuels From Oil Shale in Nashville, TN, October 1981. This paper thoroughly discusses the shortcomings of the referenced study with respect to the HYTORT process. For the interested reader, I can also recommend a June 1984 report entitled "An Economic Comparison of Five Process Concepts for Using Eastern Oil Shale," published by Los Alomos National Laboratory (LA-10106-MS, Parkinson et al., NTIS No. DE84-015981). This study applies a realistic HYTORT design (circa 1982) and indicates that HYTORT is the most econom¬ical method of processing Eastern oil shales (about $20/bbl less than Paraho). Additionally, completion of the HYTORT feasibility study in June 1983 by Phillips Petroleum Co., Bechtel Group Inc., HYCRUDE Corp., and IGT has resulted in development of designs that will make the use of HYTORT on Eastern oil shales even more economic. HYCRUDE Corp., a second-tier subsidiary of IGT, is involved in commercialization and licensing of the HYTORT process and is active in efforts to develop the Eastern oil shale resource. As such, I am disappointed to see outdated material that has the potential for adversely affecting development of Eastern oil shale resources published in MINING ENGINEERING. I can only hope that this response will serve to mitigate any negative opinions that may have been formed. Today, activity in commercializing Eastern oil shales dominates the oil shale scene in the US and indicates a realization of the potential for these shales. Reply by V. Rajaram I appreciate the updates on the HYTORT process provided by R.C. Rex, Jr. I hope that Hycrude's work will lead to the funding of a pilot plant to demonstrate that yields of greater than 200% of Fischer Assay can be achieved in a commercial plant using eastern US oil shales.

Jan 9, 1986

Evver since it first displayed an autonomous mining truck at the 1996 MinExpo show in Las Vegas, NV, Caterpillar has been building the blocks to a fully autonomous mine. In May, the company unveiled another block in that progression, the new Cat MineStar System that it says is ?the industry?s broadest, most comprehensively integrated miner operations and mobile equipment management system.? The full system is comprised of five capability sets ? Fleet, Terrain, Detect, Health and Command ? to help operators define the size and scope of their management system based on the needs of their mining operations. Michael Murphy, technology and autonomy manager for Cat Global Mining, explained that the customers were not ready for an autonomous mining truck in 1996, but that many customers wanted the building blocks to eventually get to autonomous mining. After 15 years of work, Murphy said the building blocks have come together in the form of the Cat MineStar System.

Jan 1, 2011

By Gino Vogt

In mechanized tunnelling operations performance, consumption and safety are main factors for jobsites. One of the most important components effecting these factors, especially in slurry TBM operations, are Slurry Treatment Plants (STPs). Inadequate/ suboptimally dimensioned and designed STPs create bottlenecks for tunnelling operation and jeopardize time schedules and performance. Inefficiently planned STPs could drastically increase consumption figures such as electrical power, bentonite, water and polymers, etc. Inaccurately selected and treated suspension properties can cause a high-risk potential for the whole job. This paper debates the relevant key parameters for STPs from start to finish of a project and its results in influencing factors from the manufacturer´s point of view.

Jun 13, 2021

By Lauren M. Roberts, Ralph R. Sacrison

Pipeline or borehole free-fall transfer of material has long been done in support of underground mining. This paper addresses some characteristics and design elements in selecting systems suitable to the transferred media and the mine requirements. Though aspects of overall systems are discussed, principal attention is directed to the slickline/dropline/transfer line and the discharge diverter/rockbox/energy dissipator/boot. These terms are common to these systems, often used interchangeably, and will be used as appropriate to the material, equipment and construction. Following several design sections, fabrication and construction, and system operating and maintenance procedures are discussed.

Feb 1, 2025

By William Gleason

"The mining industry tends to focus on very large numbers, whether it’s talking in terms of size of deposits, tons of material mined, the equipment used or the dollars spent. The numbers associated with mining projects are often in the hundreds of millions, but sometimes it’s the little things that can have the biggest impact.Take, for example, the Rosemont Copper Project in Arizona. Owned by HudBay Minerals, the Rosemont Copper project, when in production, is expected to be one of the largest copper mines in the United States, accounting for about 10 percent of total copper production with annual production expected to be 110 Mt/a (243 million lbs/year). However, the project is currently mired in a years-long permitting process. At the 2017 SME Arizona Conference in Tucson, AZ, Kathy Arnold, director of environmental and regulatory affairs for Hudbay Minerals, spoke about the project and the efforts to get it into production.She opened her presentation with the unfortunate news that her 2017 presentation would not be that much different than the 2016, 2015 or 2014 presentations she gave to the same conference. That’s because, as of Dec. 4, 2017, the project had been in the permitting process for 3,797 days, more than 10 years. The process began when Rosemont submitted its initial mine plan in 2006 and a revised one in 2017. The official start to Rosemont Copper’s National Environmental Policy Act (NEPA) started in 2008.In June 2017, the project received its Final Record of Decision from the U.S. Forest Service, moving it a step closer to production. Yet it still faces stiff opposition from opponents while it works to secure the Clean Water Act Permit from the U.S. Army Corps of Engineers and to complete its final mine plan of operations.In her presentation, Arnold said the long process taught her many lessons, including approaching things with a different mindset. More than 130 pages worth of public comments have been collected over the years. The concerns expressed range from lighting issues to pavement to preserving land for a jaguar that was spotted on the property and named El Jefe.“A lot of things that people worry about seem to be small things, but we had to have a different mindset and be open-minded to the concerns,” Arnold said. “That is the commitment we made.”"

Jan 1, 2018

By Dapeng Zhang, Brij Moudgil, Shibo Zheng, Chunhui Feng, Wenyi Song, Wending Xiao, Patrick Zhang

The separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. More than 50 percent of the phosphate reserve in Florida contains too much dolomite to process using current industry practice. The current way of producing phosphoric acid requires less than one percent MgO in the phosphate concentrate as the feed material. The Florida Industrial and Phosphate Research (FIPR) Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered three feasible options. Option I entails three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand, which could reduce MgO content in the final concentrate by 20 to 40 percent. Option II involves the crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9 percent MgO at about 87 percent P2O5 recovery. Option III is a gravity separation technique using an innovative separation jig, and its full potential remains to be demonstrated.

By Art Hamid, Manfred Wong, R. John Caulfield

"The proposed Channel Tunnel is a critical component of the San Francisco Public Utilities Commission’s (SFPUC) Central Bayside System Improvements Project (CBSIP), which is a key element of a $6.9-billion sewer system improvement program to upgrade its aging and seismically vulnerable wastewater facilities. The tunnel will provide gravity conveyance and storage of combined sewage flows from the northeast sector of San Francisco, CA to the Southeast Water Pollution Control Plant for treatment. The tunnel will be approximately 2.7 km (1.7 miles) long and 7.3 m (24 ft) in internal diameter. It will utilize a single-pass precast concrete segmental lining system. Tunneling challenges include excavating with pressurized face tunnel boring machine (TBM) technology through highly variable ground conditions including the Franciscan Complex (rock and mélange), clayey/silty sands, stiff to hard clay (Old Bay Clay) and mixed-face conditions. The project will also require several deep shafts that will be technically challenging. Project backgroundThe SFPUC is a department of the City and County of San Francisco, CA that provides municipal power, drinking water and wastewater services to San Francisco.San Francisco’s combined sewer system collects both wastewater and stormwater in the same sewers, which is then pumped, treated to stringent state standards and discharged into the San Francisco Bay and Pacific Ocean. The sewer system includes tunnels, large storage/transport boxes, 1,600 km (1,000 miles) of collection sewers, 28 pump stations and three wastewater treatment plants. After decades of service, much of the system is nearing the end of its useful life.The existing system is also vulnerable to seismic damage. During the 1989 Loma Prieta earthquake, damage to SFPUC wastewater infrastructure was extensive. This included the 3,415 m (11,200-ft) long, 1.7m (66-in.) diameter Channel Force Main, built in 1976, and a critical component of the conveyance system. The Channel Force Main carries 70 percent of the bayside dry weather sewage flow from the northern and central part of the city to the Southeast Water Pollution Control Plant for treatment. It is antiquated, not pile-supported and not constructed to current seismic codes. There is also currently no conveyance redundancy for north/central bayside flows to the treatment plant. Figure 1 shows the SFPUC’s wastewater collection system, the existing Channel Force Main and the project location."

Jan 5, 2017