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By M. Jessop, V. O. Kofoed, R. Blanchard, A. Hughes

Willowstick has successfully employed a new Seismic Acoustic Resonance (SAR) method to improve seepage characterization through, beneath, and around dams. SAR is a passive seismic method that detects zones of higher permeability in the foundation and fill materials of a dam. Just as the ocean has tides, the earth’s crust experiences daily “Earth Tides” and is constantly in motion. Continual motion produces resonance signals that can be measured, interpreted, and modeled to identify zones of higher permeability within a dam and its foundation. The SAR results are analyzed in conjunction with the traditional Willowstick Method to better characterize seepage flow paths and patterns trough, beneath, or around a dam in three dimensions. When both methodologies, which use entirely different scientific principles, identify the same anomalous feature, a higher degree of confidence is gained in the results of the investigation. Willowstick has effectively utilized the SAR method on many successful dam seepage investigations. The two geophysical techniques when used in parallel have yielded complimentary results, with both methods providing beneficial information about seepage locations. This paper will detail seepage flow paths identified using both Willowstick and SAR methods for two case study tailings dams in Canada and the United States.

Feb 1, 2023

By C. D. Anderson

A variety of processing technologies exist for recovery from both primary and secondary sources of rhenium. Currently, there are no known primary rhenium deposits; thus, the method in which primary rhenium is produced is dependent on the commodity of which it is a byproduct, e.g., copper, molybdenum, uranium, etc. In addition, focus on the recovery of rhenium from secondary sources, such as alloy scraps and catalysts, is continually growing. This paper presents a review of both primary and secondary processing technologies for the recovery of rhenium.

By A. A. Schweizer

Buckhorn ore is hydrous, argillized basaltic andesite, and is at least 60% clay composed of kaolinite and subordinate montmorillonite. Moisture content runs from 10% to 25%. The original crushing plant was a typical compression type, employing a jaw crusher, and two cone crushers. The system was plagued with constant plugging and unable to meet production plans. The three compression crushers were replaced with a Stamler Feeder Breaker followed by a Hazemag Impactor. Production plans are now exceeded. Agglomeration has progressed from an agglomeration drum to cascading conveyors, to introduction of the lime and cement into the primary crusher.

Jan 1, 1987

By Nathaniel Arbiter

After almost 60 years of application in this country froth flotation is still by far the most important process for concentrating metallic ores as well as a number of nonmetallic ores including fluorspar, phosphate rock, and potash. Its use on iron ores and coal is increasing. In the metals groups the largest plants and the greatest progress are found in copper and molybdenum mills, and the section of this paper that deals with applications will be found most pertinent to that field. During its long reign the flotation process has passed through several phases of evolution and has achieved progress in economy, efficiency, and simplicity of operation. Much of today's success in the flotation of low-grade ores can be attributed to that progress. Even more important to us than our ability to cope with today's conditions are tomorrow's problems, which we can contemplate with some prescience and confidence. Our annual production of copper, lead, zinc, and molybdenum--to mention only the most important metals occurring in the U.S. as sulphides--must be held at a high level in the face of a declining grade of ore. It is probable that the tonnage of such ores mined and processed will double in this country before the turn of the century. Not only will many of the existing flotation mills be enlarged again and again, but larger mills will be built here and abroad to meet our needs. At this moment, in fact, there are at least three proposed new foreign mills or expansions that envision 100,000 tons daily milling rate on copper ores. Table I (1) shows the trend in copper ore grades in U.S. in recent years:

Jan 1, 1970

By Garland R. Dever

Limestone resources for industrial, constructional, and agricultural uses occur on the surface and at minable depths in several areas along the Ohio River and its navigable tributaries in Kentucky. Operable thicknesses of high-calcium and high-carbonate limestones suitable for use in cement and lime production, steel manufacture, environmental-control measures, and other special uses are documented in Ordovician and Mississippian formations by analysis of 0.3-meter (foot-by-foot) samples. Active and potential mine and quarry sites afford access to water transportation and proximity to a number of industrial and metropolitan centers. Geologic factors affecting the distribution of deposits include the Cincinnati arch, regional dip into the Appalachian and Eastern Interior basins, complex faulting in and near the Western Kentucky fluorspar mining district, and late Paleozoic erosional unconformities in northeastern Kentucky.

Jan 1, 1977

By A. S. Atkins

The interest in the use of micro- organisms in the leaching of sulphide minerals has been traditionally exploited as a scavenger process for the recovery of valuable metal by- products from waste ore dumps. Environmental concern on sulphur emission from conventional pyrometallurgical plants together with the cost of stack cleaning systems to comply with legislative control also indicate baccerial leaching to offer a low cost treatment for the processing of sulphide minerals. The paper describes the effect and limits of relatively coarse particles on the complete leaching of pyrite and its importance to the practical application in dump leaching operations of sulphide minerals. It has also been demonstrated that static leaching techniques have encouraging economic potential for process plant operations compared with agitated leaching systems.

Jan 1, 1984

By R. W. Bruce

The normal practice for processing complex sulphide ore has been to grind with steel balls and/or rods in steel mills before flotation. Little thought had been given to the effect of grinding media on flotation selectivity of copper-lead -zinc ore until 1960 when Rey and Formanek(1) published their experiments on sphalerite floatability after grinding in a porcelain mill with ceramic pebbles. The studies by Rey and Formanek had a pronounced effect on the milling of copper-lead-zinc ores in Canada and possibly throughout the world at a time when autogenous grinding was creating a great deal of interest. The impression was created, and possibly still exists with some mill men, that grinding an ore in the absence of steel will result in a loss of selectivity between copper, lead and zinc minerals. This is in spite of the fact Rey and Formanek's experiments showed that the "naturall floatability" of sphalerite was not apparent after grinding in a porcelain pebble mill in an alkaline pulp.

Jan 1, 1976

By Peter Dietrich, Joseph DeMello, Norbert Fuegenschuh, Kerwin Hirro, Jeff Brandt, Mike Cole

This paper presents a successful case history of the ground improvement efforts and excavation of twenty-three cross passages between twin bore tunnels driven by EPB tunneling machines in Los Angeles, California on Section 1 of the Westside Subway Extension. Unique and complicated ground conditions local to the tunnel alignment include San Pedro sands, siltstone/claystone Fernando Formation, and zones of “asphalt impacted soils.” To provide water cut-off and soil stabilization, jet grouting was performed prior to TBM excavation at the location of many of the cross passages. However, upon investigating the cross passages prior to excavation, the subsurface conditions required additional measures and SEM tools to ensure successful completion of the project.

Jun 13, 2023

By Yuexin Han

The characteristics of comminuted hematite products using a high pressure grinding roller (HPGR) and conventional jaw crusher (JC) were comparatively studied by screening, optical microscope, scanning electron microscope (SEM) and Brunauer, Emmett and Teller (BET) techniques. Major properties investigated included product size distribution, particle cracks, specific surface areas and pore volumes. Results showed that in a closed-circuit operation with a screen opening of 3.2 mm, the HPGR and JC gave a similar P80, but the HPGR achieved a more uniform size distribution, more fines and a higher crushing efficiency. Three modes of cracks were identified, namely transgranular cracks, innergranular microcracks and intergranular microcracks. Transgranular cracks originated from shearing breakage. Innergranular and intergranular microcracks were generated by HPGR via the two main nonrandom breakage forms, preferential breakage and interfacial breakage, depending on their respective ability to endure stresses when mineral phases (particles) were loaded against each other. The BET values for the same-size fractions showed that HPGR products gave higher specific surface areas and more pore volumes than JC products. This indicates that HPGR-crushed products are easier to grind because of their high porosity and extra cracks.

May 1, 2012

By W. D. Delahaut

Sampling tests performed at the Paradise Peak Mine compared various blasthole samplers and reverse circulation sampling methods. Statistical analysis of the data indicates that be-low-the-deck bag sampling produced a 24 to 29 percent error when compared to bulk sampling methods. Use of a chip pile wedge sampler reduced error to 17 percent. Reverse circulation sampling upgraded over bulk blasthole sampling by 7 percent for gold and 11 percent for silver. These results indicate that bias sampling conditions exist when small volume bag sampling is employed in production blasthole drilling.

Jan 1, 1991

By J. N. Hartley

Uranium mill tailings, waste products of uranium extraction, contain hazardous constituents that if released into the atmosphere and groundwater could threaten our health and environment. To provide for safe disposal and control of these tailings, Congress enacted the Uranium Mill Tailings Radiation Control Act of 1978 (Public Law 95-604). Subsequently, the Environmental Protection Agency (EPA) established standards for tailings disposal that limit radon emission into the air to 20 pCi m-2s-1 on an annual average basis (EPA 1983). The design life of the impoundment is to be 1000 years where practicable, but 200 years at least. To facilitate the design of containment systems that will meet the EPA standards, the Nuclear Regulatory Commission (NRC) and the Department of Energy (DOE) are sponsoring research at the Pacific Northwest Laboratory (PNL)* to develop the necessary technology. Earthen and asphalt materials have been evaluated for use as radon barriers (Hartley 1983) and as liners to minimize leaching (Buelt 1983). Herbicide and rock barriers against biological intrusion have been evaluated (Cline 1982). Surface stabilization techniques have been investigated to maintain the long-term effectiveness of a containment system that must be protected from wind and water erosion, chemical and physical degradation, and biological disturbance.

Jan 1, 1984

By TOMI GIORGIO DE, Ricardo Tichauer

Mineral exploration is a key factor for success in the mining industry. However, exploration best practices are often ignored in small-scale mining. This works presents the Tichauer-DeTomi Matrix, a methodology that measures the level of compliance of exploration programs in small-scale mining with the industry best practices. The matrix has been applied to three projects in Brazil: an artisanal gold mine in the state of Pará, a small-scale manganese project in the state of Bahia, and a small-scale manganese project in the state of São Paulo. The application of the matrix resulted in indexes that represent the level of maturity of the exploration program in each project and indicate priority actions for reduction of the geological uncertainty. Therefore, the Tichauer-DeTomi Matrix has shown potential to be a useful tool for assessment of geological uncertainty in small-scale mining. As a risk indicator, it may contribute to promoting investment in small-scale mining and development for communities that depend on this activity around the world.

By George W. Heunisch

The properties of Neutra-Fix® and Neutra-Ment® , two new lime substitutes for the treatment of acid mine drainage (Arm), have been compared with lime and Alkament®, two products presently in use for AMD treatment. The two new products are basically dolomitic byproducts and produce sludges that are more compact than those from lime. Sludge settling rates are faster than lime with iron concentrations after 24 hours that comply with EPA regulations. Material utilization and optimum pit are reported.

Jan 1, 1984

By W. D. Macleod

This paper describes a mineral dressing process for the upgrading of tin ores. The process described is called 'agglomeration' and. is similar in many respects to flotation. Many variables have been examined experimentally both on batch and continuous operations and are reported upon herein... Using a Mt. Pleasant tin ore, assaying 0.5% Sn, an upgrading to 8% Sn, with a recovery of 95% could be obtained by this process.

Jan 1, 1966

By D. R. McMullin

The purpose of this paper is to provide a method for mine planners and engineers to evaluate on a conceptual basis if a shaft or a ramp is most suited for their particular underground access requirements. Mine planners and engineers are often raced with the decision of choosing which method of underground access is best suited for their particular requirement. Underground access can be provided by a shaft, ramp, adit, or slope for either exploration and/or actual production operations. This paper will focus on the construction cost and schedule differences between sinking a shaft and excavating a ramp which are currently the most typical access alternatives used in the western United States. It would be wrong to state that one method is superior to the other in every case. There are many variables to be addressed, and the degree of sensitivity of each of them will eventually dictate which method is the most suited to the particular circumstances. This paper compares the construction cost and schedule or sinking a shaft to excavating a ramp at different depths given different ground and hydrological conditions. This comparison provides mine planners with "rules or thumb" that may be applied to the access selection process.

Jan 1, 1994

By C. D. Elifrits

The required reclamation of land disturbed by surface coal mining often results in the creation of some over steepened slopes which are prone to rapid erosion and sediment production. This natural activity on such slopes is not desirable nor allowed under current regulations. Experience has indicated that novel approaches must be devised to address the problem. Research conducted on field sites in Missouri has indicated that construction, during the reclamation and grading processes, of a man-made drainage system will control the erosion. The drainage system must replicate or exceed the natural system in terms of drainage density and channel frequency. Basic design considerations will be summarized in this paper and field results shown.

Jan 1, 1986

By William Gleason

The mining industry is under immense pressure to not only meet increasing demand for minerals, but to do so in an environmentally safe and sustainable manner. Growth in electric vehicles, battery storage, renewable energy infrastructure and data centers to power artificial intelligence (AI) has led to an unprecedented demand for minerals such as copper, lithium, rare earth elements and others. The need for these minerals for national defense has only increased the pressure on the mining industry. Increased geopolitical tensions between the United States, China and Russia has added a sense of urgency as supply chains have become a focal point for the U.S. Department of Energy (DOE) and Defense (DOD) and other government agencies. The International Energy Agency (IEA) predicts that copper demand is expected to grow by 50 percent by 2040 while demand for lithium could increase eight-fold by 2040 and demand for nickel and cobalt could double. The challenges to meet the increased demand include technological, workforce, exploration and environmental issues. From Feb. 22-26, the global mining industry will converge on Salt Lake City, UT for the MINEXCHANGE 2026 SME Annual Conference & Expo where these challenges and others will be addressed by some of the leading minds in the industry. Included in this year’s conference is the Resilient Energy in Mining Symposium, a symposium with input from across SME that looks to address some of the most significant challenges the industry is facing. “Adopting environmental, social and governance (ESG) best practices has become a necessity for the mining industry, not an option. The Resilient Energy in Mining Symposium is crucial for MINEXCHANGE 2026 because it addresses the complex challenges of transforming traditional mining operations to support a sustainable and secure energy future,” Lisa Gonzales, principal engineering at Arcadias and MINEXCHANGE 2026 SME Annual Conference Chair and chair of the Resilient Energy in Mining Symposium said. “Mining is inherently energy-intensive, yet it is also foundational to the global energy transition, supplying the critical minerals needed for renewable technologies. By bringing together industry leaders, the symposium fosters collaboration and actionable change, showcasing advancements and real-world solutions that demonstrate the tangible benefits of resilient energy strategies. This unique forum enables knowledge sharing, inspires innovative thinking, and helps set the standard for sustainable practices across the sector.” The symposium was created in direct response to a SME member survey in 2023 conducted by the Responsible Mining and Underground Construction (RMUC) Strategic Committee. “The survey highlighted a strong demand for technical resources on energy transition, carbon reduction, renewable power, climate change, and ESG reporting,” Gonzales said. “To address this, I collaborated with RMUC to engage committee members from all SME Divisions, ensuring a diverse and comprehensive platform that reflects every aspect of mining. We intentionally structured the symposium to centralize key content and minimize duplication across divisions.”

Jan 1, 2026

By Justin R. Patts, Andrew B. Cecala, A. KYLE LOUK, Emily J. Haas

The National Institute for Occupational Safety and Health (NIOSH) and the former U.S. Bureau ofMines (USBM) have given a significant effort over the past four decades in researching and developing engineering controls and interventions to reduce mine workers’ dust exposures during the bagging and palletizing of industrial minerals. Workers performing manual bagging and palletizing of 50- to 100-pound bags typically have some of the highest dust exposures of all workers at mining and mineral processing operations. This paper will provide an overview of available dust control technologies for bagging operations and present the findings of a recent case study that was conducted at four different industrial sand operations to identify the current types of bagging and palletizing technologies being used and to evaluate their effectiveness in reducing workers’ exposures to respirable crystalline silica dust. An evaluation will also be performed to determine if further reductions in respirable dust levels can be achieved by incorporating additional modifications or improvements into the existing technology.

Apr 3, 2020

By C. L. Lin

A PC image-based on-line coarse particle size analyzer has been developed to measure particle size distributions under plant situations where overlapped particles are being transported on a moving belt conveyor. Although previous testing had shown satisfactory performance of this image-based system for separated particle size measurements (the non-overlapped case), it was necessary to modify original algorithms in order to solve the overlap problem and make the system suitable for plant operations. On-site testing has been conducted at a large copper concentrator in the southwestern U.S. for further investigation of the overlap problem.

Jan 1, 1995

By C. E. Golson

Modern concrete technology emphasizes the basic qualities required of an acceptable aggregate: it must be clean, sound, homogeneous, and of a size gradation resulting in a concrete of the desired physical qualities at a minimum cost. In the case of coarse aggregates, crushing, scrubbing, and screening will usually provide the required material, although beneficiation is often necessary in order to eliminate unsound or deleterious fractions. Beneficiation is also applicable to fine aggregates,( but the processes most often employed are washing, classification, and dewatering.

Jan 1, 1959