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By A. J. Naldrett

Over the past six or seven years important new ideas have been developed concerning the origin of nickel sulfide deposits. To a large extent these have been stimulated by the major nickel discoveries of the Eastern Goldfields area of Western Australia (Woodall and Travis, 1969; Ewers and Hudson, 1972). Prior to these finds, the most important nickel camps were regarded as being associated exclusively with intrusive rocks such as the Nickel Irruptive at Sudbury or the intrusive peridotites at Thompson, rocks that were thought to have no close association with volcanism. Study of the Australian discoveries, coupled with work in South Africa (Viljoen and Viljoen, 1969) and Canada (Naldrett and Mason, 1968; Pyke, Naldrett and Eckstrand, 1973), has shown that volcanic rocks with true ultramafic compositions and extrusion temperatures of 1400 to 1600°C were a common feature during the Archean. Under certain circumstances economic concentrations of nickel sulfides have formed from these rocks, either settling to the base of their associated flows or accumulating in shallow intrusive feeders to the flows. The aim of this article is to show how these ultramafic rocks can be recognized, how the nickel deposits, if present, are likely to occur within them, and what special features characterize ore-bearing examples of the rocks.

Jan 1, 1975

By K. L. Wiley

In-situ leaching, initiated in 1986 at San manual, was economically developed in 1989. The primary reason for this lag time between startup and viable production was the time required for technical development. The technical development pursued comprised detailed design, development, and implementation of in-situ well construction methods, formulation of suitable well pattern arrays, and the development of extensive hydrogeologic and geochemical knowledge of the mineral deposit. Since 1989, the in-situ leaching program has become a viable and cost effective method to extract copper from the supergene mineralized zone of the San Manuel deposit. The in-situ leaching methods that are currently utilized have been progressively expanded and continually developed and will became the cornerstone of copper production from the San Manuel oxide mineral deposit. This paper presents an overview of the supergene hydrogeology, current design techniques, drilling methods and well completion, pump determination and setting, solution management, and future plans for the increased extraction of copper by in-situ leaching methods at the San Manuel mine.

Jan 1, 1993

By Erwin Riyanto, Roy William, Karl Llewellyn

The Deep Mill Level Zone (DMLZ) mine is currently one of the deepest block cave mines in the world. The rock mass is heavily veined with little to no joints and faults are usually healed cohesive structures leading to difficult cave mining conditions. The caving process is improved if the rock mass contains fractures with sufficient density that it will cave by gravity as undercutting progresses. Hydraulic fracturing (HF) has been used to create fractures around the cave to improve mining. A seismic monitoring system has been used in DMLZ since the start of mining. Therefore, the seismic activities before, during and after HF can be monitored. Shear wave splitting is a process used to study the impacts of HF on the rock mass. This process involves the measurement of travel times from splitting shear waves after seismic events and using this to define the anisotropy within the rock mass and subsequently fracture density. This paper sets out the methodology for carrying out the interpretation of the shear wave splitting process using seismic data from the fracked cave crown and abutments along with an overview of the benefits to cave mining as result.

Apr 26, 2022

By Rafael Fernandes Reis, Leonardo José Silva de Oliveira, Rodrigo Seara Martins

Alterações na cristalização dos pós fluxantes durante o processo, devido variações de composição química pelas reações metalúrgicas na interface metal/escória ou pela incorporação de compostos exógenos, afetam o fluxo de calor no molde de lingotamento contínuo. Um dos compostos importantes é o ZrO2, proveniente do desgaste da válvula submersa. A proposta do trabalho foi investigar o efeito deste composto, utilizando simulação laboratorial, na cristalização do pó fluxante e no fluxo de calor do molde. Os resultados demonstraram que quando há o incremento do teor de ZrO2 o fluxo de calor na região do menisco também se eleva. Tal efeito é crítico para formação de defeitos, uma vez que a região do menisco é crucial para a solidificação inicial do aço.

Oct 1, 2019

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016

By Mauricio Estrada, Luis Vilchez, Luis Valencia, Marco Vera, Italo Manzo

Flotation is the most used separation process worldwide. Flotation characterization is usually carried out in batch conditions at laboratory scale. A phenomenological description of the flotation process is challenging, however, the evaluation of flotation performance in a contextual manner by means of a pilot plant is beneficial to reduce uncertainty on metallurgical results. In addition, leveraging pilot plant results by digitalize them helps describe the process dynamically. Consequently, flotation pilot plant testing allows a Digital Twin (DT) to be generated by combining ore characteristics, process information and a digital architectural platform. Therefore, the generation of a Digital Twin of the flotation pilot plant provides a tool to explore and evaluate new operating scenarios. This allows an optimum scenario to be identified and scaled up (i.e., industrial operation).

Sep 30, 2022

By H Vigil, G. Peach

Long tunnels with only one access shaft pose many program problems for logistics, combine these with the requirement to drive directly out under the seabed for 10.2 km, and the program issues become even more challenging. The Musaimeer outfall tunnel was one such tunnel and to meet and eventually improve on the planned completion date required a complex and extensive management of all tunnel logistics required to support consistent tunneling for a two-year period. This technical paper will discuss the management issues and solutions implemented to meet the challenges of the Outfall tunnel construction.

Dec 1, 2022

By J. Drzymala, K. L. Wolters, T. Chmielewski, T. D. Wheelock, D. H. Birlingmair

Microflotation tests were conducted with a modified Hallimond tube equipped with a fritted glass disk and magnetic stirrer to determine whether the results would support an equation that predicts a linear relationship between particle size and the reciprocal of particle density in water for a specified flotation recovery in a given time. Data obtained with the tube for either hydrophilic or hydrophobic solids fit the equation satisfactorily. It was also shown that the natural flotability of molybdenite is somewhat less than that of elemental sulphur and that sodium dithionite is a good depressant for sulphurised pyrite. In addition, it was found that the untreated pyrite and galena used in the study were hydrophilic and did not float by particle-bubble attachment.

Jan 4, 1992

By Horry Parker Jr, Jason Gillespie, Justin Kolster, Stephen O’Connell

Construction of the 5,932-ft Reedy River Basin Sewer Tunnel in Greenville, SC was marked by a critical transition from drill-and-blast mining in mixed-face conditions to TBM excavation with limited rock coverage. In this paper, we discuss the geological, geotechnical, and risk management considerations for transitioning to TBM operations in variably weathered gneissic bedrock. After construction of an unexpected 230-ft starter tunnel due to differing site conditions, the 11-ft diameter TBM was successfully launched in December 2019 without significant ground support issues. This project highlights the effectiveness of extensive rock probing to fully characterize bedrock topography prior to the TBM launch.

Jun 13, 2021

By Jürg Künzle

Underground construction is a matter of dealing with the inherent uncertainty of subsurface geology. If the encountered conditions are less favorable than the expected ones, the execution of excavation, support, ground treatment or lining works is likely to require more or different efforts than anticipated, thereby delaying the works and increasing the costs. The 2019 first edition of the FIDIC Emerald Book model contract (FEB) addresses many of the issues to which underground works give rise, including those related to differing site conditions (DSC). This paper examines how under the FEB disputes arising from or in connection with DSC could or should be avoided.

Jun 13, 2021

By Theodore Feldsher, Seung Han Kim, Mourad Attalla, John Roadifer, Chu-Chieh Jay Lin

Lifelines in seismic regions of the world seldom can escape crossing active faults. Cities in California have been mitigating this risk by constructing improved fault crossings. This paper discusses the analyses and design of the lining for a tunnel carrying a water conveyance pipeline through a fault that can potentially displace during a major earthquake event. The paper presents expected fault displacement, fault width and orientation respective to the tunnel, characterization of the ground surrounding the tunnel and its interaction with the lining, and performance required of the lining. Several other fault crossings will also be presented and discussed

Dec 1, 2022

By William B. Plank

NEVER before have so many men chosen the mineral technology field for their college training. In the college year 1936-'37, 7190 such students were enrolled in the 53 schools of the United States. My last study of the mineral technology schools of the United States and Canada was made for the year -1934-'35, and the current study, as the previous one was made for the A.I.M.E. under the auspices of the Division of Mineral Industry Education. Altogether, four studies of enrollment have been made. The first three were for successive college years beginning with 1932-'33. This present one covers a two-year period, for the purpose of these studies may he served satisfactorily if they are made biannually. The data on the schools were collected in the same way as for former studies, 'namely, by questionnaire, dated in this case Nov. 18, 1936. The figures reported are therefore comparable with those of former cars.

Jan 1, 1937

By H. D. Wilde

DURING 1934 conditions in the production division of the petroleum industry were reasonably satisfactory but nevertheless a decided feeling of insecurity existed largely because of the uncertainty of controlling production to consumptive demand. Over-production, especially in the East Texas field, threatened a general collapse of crude prices but in spite of this, posted prices were high. Stimulated by the prevailing posted prices, wildcatting activities were wide-spread. Although a number of small discoveries were made, particularly in the Gulf Coast belt and Oklahoma, no fields of major importance, unless it was the Fitts pool in Southern Oklahoma, were brought in. Meanwhile, the Petroleum Division of the A.I.M.E. continued its activities. It sponsored the collection of production and geological data on both foreign and domestic fields. The data on all but a few producing districts in the world were published in the "Petroleum Development and Technology" volume of the "Transactions" and comprise one of the most complete tabula¬tions of this sort ever published. Work of this kind is being continued.

Jan 1, 1935

By L. E. Young

IT has been said the British Empire was built on British Coal. In all the postwar planning for Great Britain the necessity for producing cheap coal and the prosperity of the coal industry are given first consideration. On Jan. 23, 1945, there was released in London a "Report to the Colliery Owners" which had been awaited with great interest. This was entitled "A Plan for Coal" and was the recommendation of Robert Foot, chairman of The Mining Association (Colliery Owners), prepared at their request. Presentation of the "Plan" at this time is particularly significant as it is an answer to the demand for nationalization of the coal industry by the Labour Party and at the same time is a carefully considered program for postwar reconstruction, prosperity, and stability. In the words of Mr. Foot, If the coal industry for the first ten years after this war is to find itself in a situation similar to the one it occupied for the ten years following the last war, with its record of disputes, strikes, stoppages, short-time working, unemployment, and, with it all, a completely insufficient margin of profit, and all the insecurity and instability in our basic industry that was brought with them, it is goodbye to any real prospect of full employment, social security, and high standard of living. To present an elaborate review of the conditions which have brought to a crisis the unfortunate situation in the British coal industry is here unnecessary, but certain of the salient points

Jan 1, 1945

By Elimame Elaloui, Kais Elghniji, Constantin Virlan, Aurel Pui, Chaima Ouled Amor

Separation and identification of minerals composing the Tunisian silica sands have been conducted by acid etching and hot filtration/sedimentation (HFS) without affecting the quartz component. It was found that the hot acid etching process is an effective method to separate quartz and clay minerals in the silica sand. The SEM micrographs of the silica sand show rough surface and some cracks with irregular shapes. The surface becomes clean and smooth after acid etching process. After chemical dissolution, the clay minerals were recovered by hot filtration following by sedimentation at low temperature. FT-IR, EDS maps, and secondary electron (SE) analyses of separated clay minerals reveal the presence of Fe2O3, montmorillonite, and kaolinite minerals. The LIBS analysis of clay minerals shows the presence of Al, Fe, Ca, Al, and Mg. The sequential etching process can be introduced in the purification methods as an effective way to separate quartz from clay minerals.

Jul 29, 2020

By Aziza A. Yousef, Suzan S. Ibrahim, Mahmoud A. Arafa, Mohamed A. Abdel Khalek

In view of the shortage of soft water all over the Middle East countries, seawater may be used to replace the fresh water in flotation beneficiation. The flotation process required about 7 m3 of fresh water/ ton ore. This article aimed to study the effect of seawater cations and anions on the flotation process of four important mineral commodities. The adsorption of collector, zeta-potential, zero point of charge and floatability of pure minerals were studied. The individual effects of different cations and anions that are predominant in seawater, within their more or less actual concentrations were studied on individual mineral and on groups of them. The troublesome Ca2+ and Mg2+ ions, in the anionic circuit could be controlled by soda ash addition to the pulp before the anionic collector. The addition of sodium silicate improved the floatation selectivity of mineral mixtures and natural ore. At the optimum conditions the calcareous phosphate ore yielded a concentrate recovery of 83% with a grade of 34% P2O5, with 0.61%MgO, which from an ore assaying (25.3% P2O5 and 9.4% MgO).

Jan 1, 2003

By de Vaux. Deryck, Natalie J. Shackleton, Vratislav Malysiak Cyril T. O. Connor

"The major losses of PGM and base metals in the beneficiation of platinum group deposits occur during the separation of gangue from the value minerals by selective flotation. A number of studies have shown that this negative impact on flotation is due to surface passivation, caused by various ions that may originate from the external water supply or, as is likely in the majority of cases, from the oxidation of the mineral surfaces and the grinding media. This investigation aimed at reducing surface passivation of pentlandite and inadvertent activation of pyroxene, thereby improving ultimate valuable mineral recovery and selectivity. Both synthetic minerals and plant ores were studied in order to determine the effect surface passivation and inadvertent activation have on mineral surface alteration and floatability. Zeta potential determinations, microflotation, ToF-SIMS (Time of Flight Secondary Ion Mass Spectrometry) analyses, laboratory batch flotation tests and continuous flotation testwork were used as tools to study the surface alteration and/or floatability.Zeta potential determinations and ToF-SIMS analyses showed that copper adsorption is non-selective. Both pentlandite and pyroxene become copper (II)-activated in the presence of copper sulphate and subsequently, in the presence of xanthate, adsorption of the collector will occur onto copper activated mineral surfaces. Zeta potential determinations also showed an alteration of the surface charge in the presence of polyphosphate, thereby inhibiting surface passivation of sulphides by slime coatings due to surface repulsion.The addition of diethylenetriamine (DETA) reduces the copper concentration on both minerals, predominantly on the pyroxene surfaces and polyphosphate further enhances the selectivity at pH 6.The microflotation and batch flotation data obtained has shown a significant improvement in the ultimate flotation response of valuable mineral recovery and concentrate grade compared to the standard reagent regime, while the continuous flotation results significantly improved the selectivity, however, at a similar ultimate recovery."

Jan 1, 2003

By Francis Church Lincoln

I. SITUATION AND SURROUNDINGS. THE Promontorio mine is situated at the northern end of the Sierra San Francisco de Coneto, in the town of Promontorio, Partido of El Oro, State of Durango, Mexico. As shown in the sketch-map, Fig. 1, the nearest railroad station is Chinacates on the Mexican International Railroad, 82 miles north of the city of Durango. The mine is 16 miles north of the station by air-line. It is reached by means of a good wagon-road which first crosses the Guatimapé Plain, passing the ranches of San Antonio and San Julian, to Estacion-a distance of about 15.5 miles-and then entering the mountains crosses the Sierra to Promontorio-a further distance of 11.5 miles¬making in all a distance of 27 miles by road from railroad to mine. Promontorio is just beyond the summit of the range, at an elevation of about 8,000 ft. above sea-level, or 1,350 ft. above the Chinacates station. The Castillo de San Francisco, the highest peak in the Sierra, has an altitude of 10,000 ft., and the Promontorio road crosses the summit of the ridge at an elevation of 9,000 ft. by a pass just below this peak known as the Puerto del Almagre. The Promontorio mill is situated at Santa Ives, 2 miles by tram or 3 miles by wagon-road to the north of Promontorio and about 600 ft. lower. The Sierra San Francisco de Coneto decreases in height towards the north and west till it comes to an end at the Melchor Arroyo on the ranches of Melchor and Ramos. Beyond this arroyo another range, the Sierra de la Candela, begins. In the vicinity of the Promontorio mine the hills are very rugged and the surface is furrowed by ravines which contain running streams during the rainy season-July, August and

Jan 1, 1908

By Robert Bell

THE " Tar-Sands." is the name which has been given to the extensive horizontal deposit of fine Cretaceous sand, blackened by tarry petroleum, which forms the banks of the last or lowest 130 miles of the Athabasca river before it terminates in Athabasca lake. The Cretaceous strata, to which these sands belong, extend northwesterly from Dakota all the way to this lake and for 500 miles beyond it. The Athabasca river forms the uppermost section of the Athabasca-Mackenzie, one of the great rivers of the world. It rises on the Pacific side of the Rocky mountains, westward of Edmonton, and flows north of east to a point called Athabasca. Landing, 100 miles north of Edmonton, where it turns northward and runs about 280 miles before it falls into the west end of Athabasca lake. The section of this river-system which discharges the lake just named into Great Slave lake, is called Slave river, and below the latter lake it becomes the Mackenzie river. Along the section of 280 miles of the Athabasca river above mentioned, the Cretaceous strata consist of bluish-gray and drab-gray marls, on top, from Athabasca Landing to Drowned rapid, 110 miles down stream; then heavily bedded gray sandstones, 225 ft. in greatest thickness, underlying these, form the banks for about 40 miles further. The strata appear to be horizontal, but they really clip very slightly to the southward. At Drowned rapid, we see the first of the tar-sands resting on almost horizontal beds of bluish-gray limestone of Devonian age. In some places the limestone is associated with shaly or marly bands. Notwithstanding the great hiatus between the two series, the horizontal tar-sands lie conformably upon the almost level upper beds of the limestone wherever the two formations are seen together, all along the river, throughout a

Mar 1, 1908

By Clara Godoy, Álvaro Dapía, Paulo Couceiro, Pablo Segarra, José Ángel Sanchidrián, Juan Navarro

This paper applies geostatistical tools in Measure While Drilling (MWD) data to estimate the probability distribution of values in all the points of the studied domain in order to assess the continuity of rock classes between boreholes. The analyses carried out by Ghosh et al. (2018) and Navarro et al. (2019) have been used as starting point of this work to classify the geotechnical rock condition in four classes: solid rock, fractured rock, cave- in rock and cavity. From it, an application for the geotechnical rock condition of orebodies have been developed, aiming at characterizing the rock before the charging the holes to minimize unexpected rock conditions and to address issues associated with charging and blasting operations. Such problems are closely related with non-optimal rock fragmentation after blasting.

Feb 1, 2020