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By M. S. Riyaz Ulla

The Hutti Greenstone belt, located in the northern side of Dharwar Craton, India, contains several promising gold fields. It is predominantly composed of meta-volcanics with minor intercalations of meta-sedimentaries. Alkali-SiO2 and Zr-P2O5 diagrams, immobile element trends, and an iron-rich trend on the AFM diagram indicate that the volcanic suite is low-potassium tholeiitic basalt. The lower Mg number, MgO-TiO2, MgO-Ni, and Ni-Zr plots reveal that the basalt was derived from a fractionated, highly evolved magma generated by 10-20% melting of the mantle at 1100°C and 5 kb pressure. The chemical variations suggest that the Hutti metabasalt represents volcanic arc rocks generated at a converging plate margin.

Jan 1, 1993

By Steve Kral

One of the world’s most successful mining shovel manufacturers believes its name is not very well known in North America, particularly in the United States. And there are plans under way to improve on that. Never mind that it is one of the largest mining shovel manufacturers in the world. Or that the mining division has 800 machines in operation worldwide, 100 of them in the United States. And the company currently holds 30% of market share worldwide and 10% in the United States. Forget about the fact that it has already sold more machines world-wide this year than it did during 1995. None of that is good enough. O&K Mining GmbH Dortmund is the mining division of Germany’s giant O&K Orenstein and Koppel. It is one of three divisions of O&K Orenstein and Koppel AG, a US$1.2-billion company. The other two divisions are construction equipment and escalators. The mining division, though, is one of the company’s most successful.

Jan 1, 1996

By Adam Bedell, Jack Raymer, Brad Crenshaw

Tunnel contracts often include provisions for pre-excavation probing and grouting for areas ahead of the tunnel heading. If grouting triggers are met, tunneling stops, and grouting is performed. There is substantial variation within the underground industry on what criteria are applied to the grout verification hole that is drilled post-grouting and before excavation resumes. The criteria for determination of the effectiveness should be dependent on the geology and local hydrogeologic conditions. The purpose of this paper is to present specific criteria that can be used by a practitioner to determine whether tunneling can resume or if additional grouting is required.

Dec 1, 2022

By EDER DOMINGOS OLIVEIRA, Leandro Viana Teixeira, Carlos Antonio Morais, Ruberlan Gomes Silva

Special attention must be considered in the production of high-grade rare earth products, such as mixed rare earth oxalates or carbonates. In the main minerals used industrially, the rare earth elements (REEs) are finely associated with impurities like calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), aluminum (Al), thorium (Th), uranium (U) and phosphorus (P). Most of these impurities must be removed to avoid losses of rare earth oxides (REOs) as well as to prevent product quality degradation and low operational performance in the downstream steps of solvent extraction or ion exchange. The present study aims at investigating the conditions required to precipitate REEs, either as rare earth oxalates or carbonates, from purified rare earth sulfuric liquor with low Al3+ and UO22+ concentrations and very high Ca2+, Mg2+, Mn2+, and SO42− impurity contents.

By L. J. Vincze

The program of study of pellet binder materials was begun by the ORF in 1963 to examine various Canadian materials as substitutes for bentonite which is imported in large tonnages (199,270 tons in 1969) from the U.S.A. for Canadian pellet plant operations. Most of the raw bentonite used in Canada originates in Wyoming, North Dakota and more recently Greece, resulting in relatively high transportation costs to pellet producers. Some Canadian bentonites available in Western Canada (Alberta) can be beneficiated for uses as pellet binders but could not compete in cost with U.S. sources due to the cost of beneficiation and the higher rail transport charges to Eastern Canada. It is difficult to find a substitute for bentonite, and many materials have been investigated by research groups but, so far, no economic substitute is in use. However, some success is apparent in studies of low cost materials such as clays, sea weed, peat moss and low grade coal, The work done by the ORF over several years has covered systematic test¬ing of Ontario clays, lignite, some types of tree bark, waste sulphite liquors of various kinds, and peat moss as binders for iron ore pellets. The major effort has been concentrated on peat moss and has included a study of the influence of different additives. Since analysis of peat moss for humic acid is difficult and time consuming, a certain amount of time was devoted to development of improved methods, the most useful of which was a spectrophotometric method based on extraction of peat by sodium pyrophosphate for determination of humic substances. In the present paper, only the most recent work concerning the use of peat moss with suitable additives is discussed in detail, since it is the most conclusive and best documented portion of the program.

Jan 1, 1971

By Michael von Seebach

High-pressure grinding rolls subject the feed material to pressures of 200 N/mm? During this process considerable size reduction and the Formation of flakes occur. This paper describes the basic consideration For design and operating of this type of mill. It is also shown that the particle size distribution resulting from this process is typical for grinding processes but untypical for crushing processes. High pressure grinding rolls are designed in size of up to 2.8 m roll diameter allowing feed material top sizes of 250 mm. The rigid frame, bearing and drive - train design allows a broad application of the high-pressure grinding rolls operating the machine in open or semi-closed and closed circuit for dry and moist feed materials. Operating results show that capacity increases of up to 100 % can be accomplished with this technology. The high-pressure grinding roll also, allows for lower operating and maintenance costs due to energy savings of up to 20 L and reduction of wear to less than 1 76 for dry and less than 0.1 5 for wet grinding. Other advantages of the high-pressure grinding rolls are smaller equipment sizes than a ball or SAG-mill for a given capacity resulting in lower building sizes with reduced capital in- vestment costs.

Jan 1, 1987

By Arthur L. Raub

During the last decade, there haven't been any great innovations in the design features of a copper concentrator. What has worked well in the past continues to work well, so that major breakthroughs have been minimal. Conservatism in the ranks also plays an important part. As a copper concentrator is not designed and built everyday, Davy was elated to have an important part in this project. This is the story of the design of the oracle Ridge Project located north of Tucson on the back of Mt. Lemmon at an elevation of 5,900 feet on the N.E. slope of the Catalinas. The Oracle Ridge property, formerly known as the Control Mine, is owned by Oracle Ridge Mining Partners, a joint venture between Continental Materials Corp. of Chicago and Union Miniere of Brussels, Belgium; both or¬ganizations specializing in the non-ferrous metal industry.

Jan 1, 1979

By Dion Weatherley, Raúl Castro, RENE GOMEZ, Pablo Cid

The study examines the impact of different drawbell geometries on hang-ups during ore extraction in underground mining. Using the discrete element method, the research compares three drawbell geometries: drawer, circular, and El Teniente. The findings indicate that the El Teniente geometry experienced more hang-up events, while the circular geometry had fewer.

Sep 1, 2023

By Bill Tucker, Mike Black

"PROJECT OVERVIEW Crossrail, Europe’s largest construction project, will increase London’s transportation capacity by 10% when it opens in 2018. The Crossrail scheme is a combination of surface and underground railway that stretches 118km east-west through central London from Reading, Berkshire and Heathrow airport in the west to Shenfield, Essex and Abbey Wood in the London Boroughs of Greenwich and Bexley in the east. Crossrail will serve 40 stations, ten of which are new, and bring 1.5 million people within 45 minutes commuting distance of London’s key central business districts. 21km of the Crossrail route comprises twin-tunnels beneath the heart of central London. It is the central section of the route, and the challenges that had to be overcome to construct its tunnels under the historic capital that forms the subject of this paper. The route of the Crossrail tunnels can be seen in Figure 1. These tunnels weave their way through the city’s underground landscape, linking eight new underground stations which connect to the existing London Underground network, providing interchanges with nine existing lines as well as the National Rail and Docklands Light Railway networks.Crossrail began construction of enabling works in May 2009 and launched the first of eight tunnel boring machines (TBMs) in May 2012. 42km of major tunneling work was completed in May 2015, and included 11km of sprayed concrete lined tunnels at the five mined stations (Bond Street, Tottenham Court Road, Farringdon, Liverpool Street and Whitechapel) in addition to the bored tunnel sections. The remaining three sub-surface stations at Paddington, Canary Wharf and Woolwich were constructed as large open boxes prior to the TBMs passing through. Crossrail, Ltd. is a special purpose company formed by the project’s joint sponsors, Transport for London and the Department for Transport, to manage design, construction and commissioning of the project. In 2009, Crossrail engaged Bechtel Ltd. as its delivery partner and a joint venture, Transcend (comprised of CH2M, AECOM and the Nichols Group), as its programme partner. The project is being managed by an integrated programme management team which is staffed by Crossrail and its partners. The railway, when opened, will be operated by Rail for London. With tunneling completed in accordance with the project’s master control schedule, the new railway is scheduled to commence dynamic testing in late 2017, with a phased opening of the tunneled sections and stations through Central London in 2018."

Jan 1, 2016

By Samuel Polinsky, Lawrence W. Bierman, Wayne Perkins

[A column float beneficiation plant using 9, 8.5 foot diameter, cells was constructed by the Simplot Company and the Smoky Canyon Facility in the fall of 1986 and has been in operation since May of 1987. The float beneficiation process was developed jointly by the Simplot Company and the Bureau of Mines (Salt Lake City, Utah) which incorporates the Bureau's bubble generator design and chemistry system based around the reverse float technology, (Albany Bureau of Mines, Application of Carbonate-Silica Flotation Techniques to Western Phosphate Materials, Rule, Dallenbach , Larsen, RI8728, 1982) . This chemistry has been modified by Simplot in both patented and unpatented improvements. The objective of the beneficiation process was to reducethe A1203 content in the overall pipeline concentrate by 0.2 wt z. Therefore, a process stream was identified in the mill circuit which provided an opportunity to isolate and treat 1100 tons per day of poor quality phosphate concentrates The process allows recovery of approximately 15% of the mill concentrates, otherwise unsuitable for fertilizer production. The alternative would have been to waste this ore. Wasting would have resulted in considerable ore loss, increased mining costs and required additional products grinding. ]

Jan 1, 1989

By Erik Marsh, Frederick C. Harris Jr., Javad Sattarvand, Joshua Dahl, Alireza Kamran Pishhesari

Based on the mine safety and health administration (MSHA)reports, mining truck accidents are among the significant causes of fatalities in the mining industry. The major causes of haulage accidents can be divided into non-driving and driving factors, such as truck-related sudden failures and operator performance. Numerous parameters affect trucks' safe operation, but situational awareness plays a significant role. Due to the distinct structure of mining trucks, making them efficient for mining purposes, the operator has a very limited field of view (FOV), making them prone to accidents resulting in losing lives. The cabin's position blocks the truck's right and rear sides, creating several blind points around it. Aiming to test/train the operator's awareness of the surrounding, a proximity detection system is developed through a multiplayer virtual reality (VR) application to investigate the human factor in equipment collisions. The operators were examined and monitored when asked to conduct what exactly happened in the Marigold mine truck accident without being aware of the scenario. After receiving sound, vibration, and visual alarm warnings, their reaction and performance were analyzed. The platform is developed using the Unity game engine for HTC VIVE virtual reality goggles. An Omni-direction treadmill and a motion simulator platform are utilized for the player and dump truck operators. Fifteen students were monitored when driving the dump truck receiving/not receiving proximity detection alarms. None of them repeated the accident when receiving proximity alarms. Also, they found the visual alarm the most comfortable while driving the truck.

Jun 25, 2023

By R. T. Hukki

The paper describes a two-stage industrial hydraulic classification system including hydrocyclones for primary classification and newly developed cone classifiers for secondary classification. Performance data based on large scale grinding and classification tests are presented.

Jan 1, 1981

By RIINA SALMIMIES, ANTTI HAKKINEN, PAULA VEHMAANPERA

Better understanding of the mechanisms and kinetics of dissolution can benefit several industrial processes. For example, iron can be leached from clays, which can be further used as a raw material in the ceramic industry. Another important application is the regeneration of ceramic filter media, which are used in the dewatering of iron ores. Dissolution of iron oxides in mixtures of acids is fairly uncommon and a less well-understood phenomenon, but it can result in a more efficient process. This work also shows that the determination of dissolution mechanisms and kinetics is not straightforward in different acid systems.

By Stephen H. Stow

Economically important heavy minerals have been studied in the sediments of offshore Alabama and Mississippi. Sandy samples have been collected from a 200 square mile area from Dauphin to Horn Islands. The minerals concentrate in sediments under 10-35 feet of water and may reach 2.4% by weight. The distribution of total heavies is related to the hydrodynamics of offshore Alabama-Mississippi; the greatest concentrations are in the Gulf where the longshore current is diverted from its westerly flow. Preliminary observations indicate that the distribution of individual minerals can be correlated with wave energy, particle size, specific gravity, and morphology of the mineral grains. The coarser, lighter minerals--kyanite, sillimanite and staurolite--are concentrated in relatively low energy areas in the Mississippi Sound and at the end of Dauphin Island in the Gulf; maximum concentration for each is 34.5%, 6.0% and 43.2%, respectively, of the heavy minerals. The smaller, more denseminerals--ilmenite, rutile, leucoxene, zircon and monazite--are concentrated in high energy areas in the Gulf; maximum concentration for each, respectively, is 42.0%, 5.9%, 9.652, 10.7% and 1.3% of the heavy minerals. On the basis of a minimum concentration of 1% heavy minerals, two areas have been identified and the total amounts of different minerals have been calculated to a depth of 25 feet of sediment. The data are preliminary and in no way indicate recoverable reserves, but they do show that on the order of 20 million tons of heavies exist. These deposits should be termed "indicated resources".

Jan 1, 1975

By B. Bag

Saturated and unsaturated fatty acids are used in the flotation of iron values present in iron ore. Among the several fatty acids, oleic acid and its sodium salt are widely used. To substantiate the flotation results, the quantum chemical calculations of a few such acids have been carried out by adopting the semi-empirical AM1 method. These acids have been further optimized in the presence of an iron atom. The electronic interaction of the polar carboxylic head group of oleic acid with the iron atom is higher compared to the other acids. The numerical results support the flotation behavior of iron ore with oleic acid. Key words: Iron ore, Flotation, Fatty acids, Quantum chemical calculations, Semi-empirical AM1 method

Jan 1, 2009

By Tuncel M. Yegulalp

This article summarizes some of the results of the continuing research activity at the Henry Krumb School of Mines, Columbia University, directed towards a better understanding of the stochastic behavior of slurry flows in underground coal-slurry pipeline systems. The slurry system under consideration here replaces all conventional haulage systems between the coal face and the coal preparation plant on the surface. At the beginning of the pipeline system, flow rate and frequency of coal slurry is very closely related to the activities of production equipment at the coal face. Due to several scheduled and unscheduled interruptions in continuous miner's coal mining activity, resulting slurry flows possess stochastic characteristics. Proper understanding of these characteristics is believed to lead to a more realissic and economic design of slurry handling equipment. Fundamental ideas supported by field observations are presented and a Semi-Markov model of the slurry flows is developed. As a result of this formulation, behavior of combined slurry flows from N independent coal faces can be expressed in analytical form. The contents of a slurry surge tank receiving slurry flows with certain stochastic characteristics is investigated as a function of discharge pump characteristics and time.

Jan 1, 1981

By Ray A. Rothrock

The in situ mining of uranium is the process whereby chemical lixiviant is injected by means of wells into, and flowed through, an ore body. The lixiviant reacts with uranium which has been previously oxidized making the uranium soluble. The solution is then brought to the surface by means of producing wells. In situ mining disturbs the ground-water quality in the immediate area. Since ground water is a natural resource used by man, care must be taken not to allow the lixiviant to escape the local mining area. Also, when the ore body is mined out, the area should be restored to as near its original state as is reasonably achievable. The return of ground-water quality to its original state can occur naturally over a long period of time or be enhanced using appropriate technological means.

Jan 1, 1981

By Sunny Schoone, Maximilian Getz, Felix Leaman, ELISABETH CLAUSEN

Hydraulic transport is commonly used in mining for moving particles or ore concentrates in pipes over long distances with a water stream. Control and monitoring of this process require sensor technology that can obtain relevant characteristics of the two-phase flow. This work investigates the acoustic emission (AE) technology for monitoring a hydraulic system with different sand concentrations, showing the strong relationship between friction behavior in the pipe and the measured AE signals.

Apr 1, 2023

By B. E. Davis

A technique was devised by the Bureau of Nines to recover coarse (plus 1.7 m) North Carolina phosphate now discarded as waste. Concentration utilizes the difference in particle sphericity between the relatively flat calcite and the rounded phosphate pebbles. Sizing, treatment in a continuous hydraulic classification system, and grinding upgraded a 17.0-pct-P205 reject to 24.5 pct P205 with a phosphate recovery of 63 pct.

Jan 1, 1985

By Roberto de Moraes

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

Feb 22, 2026