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By P. Zhang

A 1989 FIPR characterization study of the future phosphate resources in Florida showed that MgO would be a problem with both the pebble and concentrate as phosphate mining moves deeper. Since the ratio of concentrate to pebble will become higher and higher in the future, reducing Mg content in the concentrate by a small margin would allow blending of a large portion of the high-dolomite pebble. This research was conducted based on that logic. The following six approaches were tested for reducing MgO content in the flotation concentrate: (1) Adding a dolomite depressant in the rougher flotation step; (2) Dolomite flotation on the rougher concentrate with and without grinding; (3) Dolomite flotation on the cleaner concentrate with and without grinding; (4) Scrubbing the flotation feed; (5) Scrubbing the rougher concentrate; (6) Scrubbing the cleaner concentrate. Successful methods include adding a dolomite depressant in the rougher flotation, dolomite flotation on the cleaner concentrate with grinding, and scrubbing the cleaner concentrate in quartz sand. These techniques could reduce MgO content in the final concentrate by 20-40%. The flotation process could achieve a concentrate with the lowest MgO content, but it is the most expensive approach. Adding a dolomite is inexpensive and easy, but the effect is limited. Overall, scrubbing may be the most promising technology for this purpose.

Feb 23, 2014

By G. Davis

Mineral properties and mineral firms often trade at a market value that is significantly greater than the value indicated by discounted cash flow (DCF) techniques. A possible explanation is that DCF analysis does not consider the value derived from managerial flexibility. Presumably, then, at least some of the difference between DCF value and market value is due to managerial flexibility. This paper surveys the recent attempts to empirically quantify the value of managerial flexibility using option pricing theory. The results indicate that managerial flexibility, at least as measured by the option pricing methodology, falls well short of explaining the gap between DCF value and market value.

Jan 1, 1995

By Michael J. Lehnen

Slurry diaphragm walls are commonly used as both temporary excavation support walls, and permanent structural walls, for circular shafts and long rectangular structures (such as underground subway stations); however, they are not commonly used for more compact rectangular or square shafts. In these instances, a second wall is typically cast inside the slurry walls to form the permanent structure. This paper discusses the approach used on the Silicon Valley Rapid Transit Project in California to analyze these compact rectangular types of structures for static and seismic loading, and to determine whether or not slurry walls can be confidently used as both the temporary and permanent walls for two tunnel ventilation shafts.

By M. A. Gibson

Ilmenite-rich lunar deposits can be converted to liquid oxygen to support lunar base operations and space transportation propulsion needs by a Carbotek-developed process. Iron oxide in ilmenite is reduced at elevated temperatures by hydrogen in a fluidized-bed reactor to water vapor which is electrolyzed to product oxygen and recycle hydrogen. Reaction rate, thermodynamic equilibrium, and lunar-gravity fluidization behavior are key factors which have been considered. Fluid-solids behavior has been modeled from data taken at lunar gravity conditions aboard NASA KC-135 flights. Large-scale pilot plant operations are planned to complete the development.

Jan 1, 1991

By D. Tao

Reverse cationic flotation is the most widely utilized flotation method for concentrating iron ore. In this process, quartz is often floated with ether amines (R?(OCH2)3?NH2) partially neutralized with acetic acid. However, it is well known that the cationic flotation of quartz does not work well if a certain amount of slime is present in the ore slurry. To improve flotation performance, starch is often added to the flotation feed to selectively flocculate and depress the iron minerals and sodium silicate is used to disperse the silica gangue. The present study was conducted to improve the efficiency of iron ore flotation by the use of a new type of depressant for clay and iron minerals, Georgia Pacific (GP) clay binder. The GP clay binder minimizes slime adsorption on quartz and hematite particles by agglomerating clay particles to reduce their surface area. It also helps depress hematite flotation due to its unique chelating action on iron ions. The results from this study show that the GP clay binder is an effective depressant in iron ore flotation. When it was used as a substitute for corn starch, it increased concentrate grade from 60.78% to 67.67% and increased iron recovery from 71.96% to 72.90%. The combined use of GP clay binder with corn starch produced even better flotation performance, increasing iron recovery to 78.15%, while the concentrate grade remained stable at 67.08%. Keywords: Georgia Pacific clay binder, Iron ore flotation, Flotation efficiency

Jan 1, 2010

By R. A. Metz, Willard C. Lacy

Rather than attempting to present a summary of the many and highly varied papers that have been presented at this symposium on sampling and grade control, I will attempt to extract the general philosophy of analysis and approach, and attempt to identify the trend of future developments. First, the term "sampling" is used with its broadest connotations. A sample consists of a representative portion of a larger mass, and must represent the mass not only in the grade of contained metals or minerals, but also in all other respects in terms of mineralogy and mineral quality (1, 5), deleterious materials, recoverability of economic components, physical behavior, geophysical response (1), and even archaeological and environmental aspects (7, 11). The sample must be taken from a locality and in such a manner and quantity that it is representative of the larger rock mass. This calls for complete and accurate geological control and an understanding of the nature and distribution of the contained chemical and physical elements and a record of the effectiveness of the different sampling methods. Second, value of a given mass of ore material is based upon its profitability - the difference between recoverable value and costs to achieve recovery, beneficiation and sale. There is a strong movement in mining geology control toward more complete analysis in determining cutoff grades and in grade control, as illustrated by the kriging of metallurgical recovery factors as well as grade at the Mercur Mine (8). To achieve a "profitability factor" as a guide for economic mining practice requires further integration of: 1) the value of contained metal or mineral, 2) percentage recovery of values, 3) dilution of ore with waste rock, 4) addition to, or loss of value as a consequence of by-product materials or deleterious components, 5) cost of producing a saleable product plus minimum profit to justify the effort (cutoff), and 6) cost of land restoration (7, 11). All these parameters vary with the rock type, rock structure, mineralogy, depth, geometry, mining and metallurgical methods, but they must be sampled and analyzed if sampling and grade control are to reflect profitability. A wide variety of deposits has been presented at this symposium; each deposit with its own problems and special solutions. Deposits containing high unit-value components, e.g. precious metals and diamonds, present special problems in the obtaining of accurate samples and generally require statistical analysis control methods or may disregard or modify occasional high or occasional low values, based upon experience (12). Grade control may be accurate for the long term but may vary for the short term. Bulk sampling is always essential. Deposits containing metals or minerals with low unit value are very sensitive to transport costs, and they are often very sensitive to small amounts of deleterious components or differences in physical or chemical behavior. Problems of sampling and grade control change with the genetic type of deposit, with the stage of deposit development and with the size of the information base. Precious metal epithermal deposits (2, 6, 8), because of rapid vertical zonation and erratic lateral distribution of values, have always been difficult to evaluate and maintain grade control and ore reserves. On the other hand, evaluation and grade control are relatively easy in bulk-lowgrade deposits (4, 13). However, these deposits generally have a low margin of profit and are sensitive to mining and beneficiaton costs, price fluctuations and political costs. Industrial mineral deposits (5) often must be evaluated on the basis of their behavior, rather than by chemical analysis. Environmental impact generally increases with the scale of the operation, but certain elements or minerals have especially high impact effects (7, 11). In the exploration phase there is no production control of sampling procedures and careful geological observations are particularly essential. The greatest number of problems is related to the oxidized outcrop where the chemical environment of the ore body has changed and the contained values may have been enriched, depleted or values left unchanged (2, 6). Present evidence suggests that gold values may be very mobile under certain conditions (2, 6) and stable under others. Everything must be sampled in detail. Principal values and by-product or deleterious elements may vary dependent upon their position within the soil profile. Such factors as geomorphic position, erosion rate, vegetation, climate, etc., may affect the interpretation (1, 3). During the development phase it is equally easy to overtest, to have "paralysis by analysis," as to undertest (3, 6). Bulk samplng and testing are

Jan 1, 1992

By William Gleason

From Nov. 16-20, the Extraction 2025 Conference will be presented in Phoenix, AZ. The unique conference brings together the 12th International Copper Conference, the 6th International Symposium on Nickel and Cobalt as well as cross-cutting symposia. Extraction 2025 is co-organized by The Metallurgy and Materials Society (MetSoc) of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy & Exploration (SME) and The Minerals, Metals & Materials Society (TMS). The previous, and first Extraction meeting (Extraction 2018) was held jointly by these three societies seven years ago in Ottawa and was a huge success with more than 90 percent of respondents indicating interest in attending a future event. Kimberly Mills, senior process engineer at Samuel Engineering, is the lead for SME. “This installment of Extraction is featuring Copper 2025, Nickel-Cobalt 2025 as well as crosscutting symposia,” said Mills. “All three societies participate on the International Organizing Committee for the Copper Conference Series and are well situated to host this event together. TMS is also hosting the Ni-Co conference this year and agreed to include it as part of Extraction. There are many aspects that can be shared between these commodities to share information on processing technologies and to learn from each other.” SME is the overall conference chair and running the logistical aspects of the event, which includes managing all aspects of the venue and the registration system as well as tours and short courses, Mills said. “SME has many dedicated members serving in various capacities on organizing and programming committees, including Nick Gow serving as Technical Committee Co-Chair for Copper and Adam House assisting on the Copper IOC.” When Extraction 2025 kicks off, it will be focused on the metals needed for the global energy transition with a special focus on copper and nickel-cobalt. “With as rapidly as the industry is changing and the huge demands for these metals we have some serious challenges ahead of us,” Mills explained. “These challenges require collaboration, creative solutions and engaging experts, both inside and outside of our fields, with a push for sustainable sourcing, ethical supply chains, environmental and social responsibility.” The International Copper Conference was started in 1987 as a collaboration between the Institute of Mining Engineers of Chile (IIMCH) and MetSoc of the CIM. The event is typically held every four years and has always been held as a standalone or headlining event at a society annual meeting, said Mills. “Over the years, this conference series alone has brought together members of IIMCH, MetSoc, TMS, SME, the Society for Metallurgists and Miners from Germany (GDMB), the Mining and Materials Processing Institute of Japan (MMIJ), the South African Institute of Mining and Metallurgy (SAIMM) and the Nonferrous Metals Society of China (NFSOC),” she added. “Being a part of Extraction allows for even more sharing of ideas and expansion of networking. This conference has not been held in the United

Oct 1, 2025

By Michael Bayerl

The HILTI OneStep rockbolt was implemented for roadway development in German deep coal mines in 2004. The development by HILTI Company is based on a technical joint venture with RAG Deutsche Steinkohle AG. The technical development of a One-Step bolting system was required for weak strata conditions at the roadway development face. Standard resin bolting has reached the limit of performance when boreholes are squeezed and cannot be filled with capsules. In some cases the heading face is brittle and requires additional support for installation of the bolts and a person working immediately next to the borehole. The Hilti One-Step system allows automated and safe processing at the heading front and provides the key technique to avoid these problems.

Jan 1, 2009

By G. E. Bandelis

In this paper, solid bed erosion processes and the mechanisms involved when a two-phase liquid-solid mixture flows over a bed of solids in a horizontal annulus are analyzed. There are few such studies available with some authors arguing that the flow rate for erosion is always less than the flow rate for the suspension of solid particles thus necessitating further study and analysis of such phenomena. Tests were run to determine the mechanism of erosion and the erosion velocities of the solid bed formed in a concentric annulus for three flu-ids, water, a low concentration water solution of Carboxyl-methyl-cellulose (CMC), which behaved as a Newtonian fluid and a higher concentration CMC water solution which behaved as a power law fluid. Glass spheres of 2 mm nominal diameter were used as solids. The flow rate at which erosion occurred together with the mechanism of bed erosion were determined visually, while the whole process was video recorded. Our tests indicated different erosion mechanisms and different erosion velocities for the three tested liquids, with the liquid viscosity playing a major role. The first mechanism, observed for water flow, gives erosion from the front of the bed while the second mechanism, observed for the flow of the two viscous fluids, gives erosion from the top of the bed. The role of each of the parameters to erosion is investigated, whether it is turbulent flow with the turbulent fluctuations being more capable to remove the solids from the formed bed or whether it is liquid viscosity, which results in the hydrodynamic shearing force. The results demonstrate that liquid viscosity plays a role in the erosion mechanism and yields different erosion velocities of the solid bed hence, it should be taken into account when modeling flow pattern transitions for solid-liquid flows. Prior studies have not identified this and it could be the reason of the disagreement between theoretical models and experimental and field data.

Jan 1, 2006

By Jonisha P. Pollard, F. Nasarwanji, Lydia M. Kocher

This study identifies nonfatal injury incidence rates, nature of injury, work activities, glove usage, and sources of hand and finger injuries in the U.S. mining industry, as reported to the Mine Safety and Health Administration (MSHA) from 2011 to 2017. Hand and finger injuries occur at a rate of 6.53 per 1000 full-time employees, which is nearly double the rate of the next highest affected body part, the back.

Feb 24, 2022

By J. Chai, H. H. Sedarat, Gary J. E. Kramer, A. Kozak

Precast concrete segmental lining systems have been gaining widespread use in seismically active areas and a single-pass version of such a system has been developed for use on the Silicon Valley Rapid Transit (SVRT) Project in San Jose, California. The response of tunnel linings to seismic shaking is often predicted using engineering judgment, elastic closed-form solutions and numerical modeling. Such analyses generally assume a continuous structural system and hence do not explicitly model the behavior of the jointed segmental lining. A number of analyses were performed to predict radial and circumferential joint behavior during seismic ovaling and wave propagation. These analyses included a complex, three-dimensional finite element based ground-structure interaction model that incorporates inelastic constitutive soil behavior, cracked concrete properties and no-tension, frictional segment joint surfaces. The paper discusses the results of the analyses and provides guidelines for the design of precast systems in zones of high seismicity.

Jan 1, 2007

By Ivano Andreis, Giovanni Valent

The Yindaruqin Irrigation Project is designed to irrigate 57,000 ha of land in the central part of Gansu Province of People's Republic of China. Water for the Project will be diverted through an 87 Km long feeder canal which will convey 36 cubic meters per second from an intake on the Datong River. (Fig. 1) The feeder canal consists of approximately 10 Km of open channels, 75 Km of tunnels and 2 Km of siphons and aqueducts. This is the biggest self-flowing irrigation water control project in the Northwest of China and it is among the most interesting projects in China for the geological and environmental conditions. Nearly half of the investment in the Project is a World Bank Loan and contractors were chosen by means of international bidding. The Italian Company, CMC Ravenna, succeeded in answering the bidding for the construction of tunnels 30A and 38, perhaps the most difficult in the Project, submitting a TBM alternative to the conforming drill and blast contract recommendation.

Jan 1, 1993

By Phil Jones

"Dilution — planned and unplanned – remains a significant cost impairment in the mining process. A series of trials were held over a sixmonth period in fiscal year 2018 (FY18) that established the cost-benefit of new technology as it applies to the alignment accuracy of production drilling rigs in underground mining, thus confirming its ability to limit drilling as one of the causes of dilution. The trials identified three underlying factors affecting drilling accuracy, measurable by blast-hole deviation surveys of planned versus actual toe data. These were rig alignment error, collar location change/ error and in-hole deviation.The trials involved a comparison of existing rig setup processes and technology, with the new technology (Minnovare’s Production Optimizer system). The trials were undertaken in the same environment: the Cracow gold mine, an operating underground mine. The comparison first revealed the extent to which rig alignment impacts blast-hole deviation. Secondly, the new technology was proven to limit rig alignment error, thereby reducing average blast-hole deviation and increasing the number of holes drilled within tolerance by 160 percent.The increased accuracy reduced stope dilution by reducing over-break of subgrade ore. The new technology was implemented at Cracow during the latter half of 2018. Despite utilizing the new technology for just six months of the year, the mine recorded a 5 percent overall reduction in dilution for the full year compared to the previous year (FY17); from 22 percent down to 17 percent (a net decrease of 22.7 percent). Mine management attribute a significant proportion of this reduction to the new technology, along with sequencing and planning improvements. This opinion is backed by detailed stope reconciliation data taken during the trial from 28 stopes — representing 20 percent of the total tonnes mined during FY18. The data identified that stopes drilled using the new technology recorded 62.6 percent less average dilution."

May 1, 2019

By D. Leppert

Mr. Garrett brings up several interesting points with respect to the proposed API specification for "nontreated bentonite." However, although not explicitly stated, these specifications are being written based strictly on bentonites from the Wyoming/South Dakota area. Other sodium bentonites may be suitable for use as drill mud but will be unacceptable since the specifications are designed for Wyoming bentonites. Regardless of the API's intent that its specifications are intended only as guidelines, they are generally adhered to on an international basis and, for practical purposes, might as well be chiseled in stone. Estes (1986) notes that the quality of bentonite available from Wyoming producers has steadily declined since the early 1960's. The plastic viscosity: yield point (PV:YP) ratio was included in the current API 13A specification primarily to prevent excessive polymer treatment of lower quality bentonites to make drill mud. However, with development of polymers designed to control YP, this specification cannot ensure that only high-quality bentonites are used for drill mud. Nor will the new specifications for untreated bentonites. Other sodium bentonites are available. Bentonite produced in southeast Oregon demonstrates superior performance characteristics without addition of polymer or other chemicals. However, the exceptionally high purity of these deposits leads to a relatively high YP:PV ratio since the naturally high YP probably results from the higher purity and smaller particle size of this bentonite (Rath, 1986 and personal communication). These bentonites typically have a smectite component exceeding 90% (Rath, 1985), compared with 70% to 75% smectite for typical Wyoming bentonites, as determined by X¬ray diffraction and tests for colloid content. As evident from the accompanying table, the untreated Oregon bentonite has excellent rheological properties, though different from Wyoming bentonites due to the high purity. Additionally, this bentonite reacts well with polymers typically used in the oil industry, making it eminently suitable for use in a low-solids mud system. The extremely low grit content, less that 0.5% on a 75 mm (200-mesh) wet sieve, greatly exceeds the standards set for Wyoming bentonite. Optimum rheological properties are obtained at a higher moisture content than Wyoming bentonites. At 10% moisture, API 13A maximum, the clay is overdried, again reflecting the high smectite content. In summary, the specifications proposed by the API Task Group will ensure that only Wyoming producers can supply "nontreated" bentonite to the oilfield since specifications are

Jan 1, 1989

By M. C. Fuerstenau

A number of interesting and. important phenomena were revealed during a study of the response of beryl to sulfonate flotation (1). Perhaps the most important observation is the effect of various cations on flotation response. Experiments showed that in the vicinity of pH = 3. 0, about three ppm Fe.+++ increased recovery of leached beryl from about 60 to 100 per cent, whereas about four ppm Ca++ reduced the recovery from 60 to 2 per cent. With the exception of ferric iron, all of the other cations investigated reduced flotation recoveries drastically at this pH. As postulated in the paper "Sulfonate Flotation of Beryl", (1) even with low concentrations of polyvalent cations and sulfonate (on the order of one ppm), cation¬ sulfonates are precipitated immediately in solution. That is, blueish-white clouds .were noted to form after given additions of salts to. known solutions of sulfonate. Furthermore, it was also shown that one-hundred-fold more ferric iron than necessary to form the precipitated cloud had to be added to effect complete flotation. In other words, some form of solid ferric sulfonate was found to function as the collector in these systems. The form of the compound was suggested to be Fe (RSC3)2OH and that bonding to the surface occurs through the hydrogen of the hydroxyl. As the form of this compound was shown to be dependent on the extent of hydrolysis of ferric iron, it is to be expected that ferric iron will be unique in some pH region. Further, if the presence of hydroxyl in the neutral precipitated compound is of primary importance, then other cations should function similarly but at different values of pH, since they will hydrolyze at different concentrations of hydroxyl ion. To determine whether the premise of hydrolysis is correct, the study was extended to quartz systems lit the presence of various cations at various values of pH.

Jan 1, 1964

By S. S. Wang

Dialkyldithiophosphinates are a new class of flotation collectors for base metal sulfide ores. Structurally, they are quite different from the conventional collectors such as mercaptans, xanthates, thionocarbamates and dithiophosphates. Collectors Structures [Mercaptans R-SHS Xanthates R-OCS-M+ Thionocarbamates R-OCNH-R Dithiophosphates 2 R-CCNH-R' Dithiophosphinates (R) 2-PS-M+ ] In the above structural formula, R and R' stand for a hydrocarbon radical, and M+ is an alkali metal or ammonium cation.

Jan 1, 1982

By M. J. Allan, D. J. Barratt

This paper reviews current testing methods for sizing autogenom and semiautogenom mills in the North American context with comments on the necessity for test work and requirements for different circuits and equipment selection. The economics of testing and the value received are discussed.

Jan 1, 1987

By Ji Fang, Chong Fan, Fengrui Wang, Dongxin Bai

Unmanned mining technology in underground mines offers high efficiency, safety, and low cost. However, ground operators face challenges in accurately perceiving the underground environment through videos. This paper presents an augmented reality (AR) platform developed to enhance the unmanned mining process. The platform uses cameras and 5G technology to transmit high-fidelity video streams to the ground, where key targets are identified and virtual models are registered in the video to enhance the real scene. Tests in the Xinli stope of the Sanshandao gold mine showed the platform’s effectiveness in improving ground operators’ perception and production efficiency.

Jan 30, 2022

De Beers? Finsch diamond mine began operation in the 1960s as a surface project using the latest technology available. During the 1990s, the operation, located about 160 km (100 miles) west of Kimberley, South Africa, began its move as an underground mine. The earlier stages (Blocks 1, 2 and 3) of underground work at Finsch used open stope mining methods, also using the latest in technology. The mine began developing Block 4 in 2004. How-ever, studies on this level showed that block caving was a more efficient mining method than open stoping. It was during those studies that De Beers determined that Block 4 would be a good candidate for testing Sandvik?s automated truck haulage technology.

Jan 1, 2008

By P. A. Plunkert, D. E. Morse, L. McCartan, J. F. Papp

The mineral sector is a fundamental part of the U.S. economy. It contributes to the real gross domestic product (GDP) at several stages —basic (mining), intermediate processing, manufacturing of finished goods and construction. The real GDP increased by 3.5 percent from 2004 to 2005. The nominal GDP was $12.5 trillion at the end of 2005. Housing starts were up by more than 5 percent for the year, and the unemployment rate decreased to 5.1 percent in 2005 from 5.5 percent in 2004. The prime interest rate increased from 5.25 percent at the beginning of the year to 7.25 percent at the end of the year. The value of minerals mined in the United States in 2005 rose significantly because of increased unit prices for some metals —particularly molybdenum — and significantly increased production for some industrial minerals, mainly cement, construction sand and gravel, and crushed stone.

Jan 1, 2006