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By Louay Owaidat

The United States Army Corps of Engineers (USACE) Sacramento District awarded a $64 million construction contract in February 2020 to the Maloney Odin Joint Venture for 3 mi (4.8 km) of levee improvements along the Sacramento River East Levee (SREL). This project kicked off approximately $1.5 billion of work to upgrade levees along the American and Sacramento Rivers and widen the Sacramento Weir and Bypass. The project received the 2021 ASCE Region 9 Project of the Year Award. Contract 1 improved levees along five segments of the river, the longest segment being a 2 mi (3.2 km) reach from Garcia Bend Park to the Freeport Intake Facility in the Pocket neighborhood of Sacramento.

Oct 1, 2022

By Klaus M. Hahn, Hermann Wotruba, Bernd G. Friedrich

"Due to an increasing demand for nickel and cobalt and the depletion of nickel sulphide deposits worldwide, the production of ferronickel from lateritic nickel ores becomes more significant. About 60 percent of nickel reserves are present in laterite deposits. Common production methods like acid leaching or smelting operations implicate high material and energy consumption. Physical processing methods are also not efficient, because of the fine microstructural intergrowth of the minerals carrying valuable elements such as nickel and cobalt. Due to the high energy consumption of metallurgical treatment of lateritic nickel ore (nickel grade: 0.8 - 3.0%, Co: 0.05 - 0.15%), the separation of waste material (about 75 - 85%) before the metallurgical treatment is desirable. Therefore, an alternative process has been developed, combining a pyro-metallurgical pre-treatment with selected mechanical processing methods. The developed process consisted of a selective pre-reduction and non-selective segregation of the contained metal phases in the first stage. By this, the properties of the metal carrying minerals were changed and could become subject to concentration by means of fine beneficiation processes afterwards. The parameters of the pre-reduction and segregation were varied and the pre-treated samples were examined concerning their efficiency of metalization grade and metal grain size. This paper describes the investigation of pre-treatment methods of a lateritic nickel ore. The pre-treatment and possible subsequent separation methods were examined with regard to the recovery of the valuable elements. Metalization grade was around 80% for both Ni and Co with metal phase grain sizes below 20 µm. Scanning electron microscopy revealed distribution of new metal phases not only on the reducing agent, but also on the “slag” material.INTRODUCTION Nickel laterites are characterized as strongly weathered regoliths with several zones containing reserves of nickel (Ni) and cobalt (Co). These laterites are formed on serpentinites and ultramafic rocks under climatic and/or tectonic conditions that have changed over time (Butt & Cluzel, 2013). The formation of Ni laterites is influenced by numerous geological and environmental factors. In general, there are three ore types named according to the dominant Ni hosting minerals: oxides, hydrous magnesia (Mg) silicates and clay silicates (Butt & Cluzel, 2013). The most Ni laterite deposits contain two of these ore types, usually an oxide zone and an either clay or Mg silicate zone. Distribution of these principal deposit types, their average Ni-bearing phases and mean Ni grade are shown in Table 1. A schematic profile of the different deposits based on the development on serpentized ultramafic rocks is given in Figure 1 (Butt & Cluzel, 2013)."

Jan 1, 2018

By R. Debkowski

Mining methods used to protect the workings in underground salt mines against the destructive activity of natural factors are presented in this paper. Major hazards and methods of elimination of their impact on the stability of workings, were determined. Old and modern technical means and technologies used for protection and preservation of the selected most interesting sites were characterized. The results of surveys and studies allowed proposing the change of mine structure i.e. dividing it into monumental and not-monumental part, which should improve execution of necessary protective works.

Jan 1, 2006

By John B. Goodman

A LOW-TEMPERATURE carbonization assay test is described, and factual data derived from this test are presented. The test procedure outlined in this report incorporates a mild-steel retort of improved design, an accurately controlled method of heating, and a complete collection and condensation system for the solid, liquid, and gaseous products of carbonization. The test described establishes, under closely controlled conditions, the relationship of temperature to yields of products on carbonization. Noncoking or weakly coking coals and other carbonaceous material are particularly amenable to testing by the assay. Mass balances of 100 percent± 0.3 are obtainable by this test. It is believed that the efficiency of the test and the accuracy of the type data obtained have been materially increased.

Jan 1, 1953

By D. R. Nagaraj

There are few organic ligands that can adsorb effectively on noble metals, especially gold, in aqueous media. Ligands containing sulfur and nitrogen donors are known to be the most effective. Dithiophosphorous acids, for example, are known to adsorb on gold under certain conditions and these, along with xanthates, are used traditionally to recover gold values by flotation from ores. These compounds, however, are not necessarily selective for gold since most of the associated sulfide minerals are also floated. Monothiophosphorous acids, on the other hand, were recently discovered to float gold values selectively from sulfide-containing ores in a mildly alkaline medium; thus the dicresyl monothiophosphate is now used commercially in a gold flotation operation in the U.S.

Jan 1, 1991

By J. Eric Belford

The Kidd Creek orebody is a massive base metal sulphide deposit with surface dimensions of 168 m by 670 m. The steeply dipping ore- body has been evaluated to a depth of 1 524 m. To date, the mining of the orebody has been divided into three stages. The first stage of mining was an open pit operation which supplied ore from 1966 until 1977 when a depth of 219 m was reached at the widest or north end of the orebody. The second stage of mining, called No.1 Mine, was the development of an underground mine to replace the pit and recover the ore from the floor of the pit to a depth of 792 m. Development of the underground mine started in 1969. Full production of 273 000 tonnes per month was attained in 1977. The third stage of mining called No.2 Mine, was initiated to accommodate a production expansion and included the development of a second underground mining operation to recover the ore from the bottom of No.1 Mine, i.e. the 2600 level; to a depth as yet undetermined but most likely the 4600 foot level. Development of the No.2 Mine began in 1974. Full production of 91 000 tonnes per month will be achieved in 1982. The choice of the 2800 level as the partition between the two underground mines was based on the following factors: The 2600 level is the lowest level which can conveniently be mined through the No.1 Mine crusher on the 2800 level. Development and trial stoping methods for mining at depth could be evaluated in the 2600 to 2800 block utilizing the existing hoisting facilities of No.1 Mine. Early development of the ore in the 2600 to 2800 block would provide additional mill feed sooner than could be achieved by developing from No.2 Shaft. The underground mining plan then is to mine from the pit floor down to the 2600 foot level and at the same time mine from the 2800 level down to at least the 4600 foot level. PLANNING The Kidd Creek operations are designed to follow a logical mining sequence. The grade of ore supplied to the concentrator is the result of following the mining plan. The philosophy of mining has been to mine downward in horizontal slices. In the case of No.1 Mine the slices are 122 m thick while in No.2 Mine the slices will be 183 m thick. The point of this approach is to mine the pillars immediately after creating them rather than allowing them to stand, deteriorate and generate uncontrollable situations. Two types of ore are handled separately to optimize recoverable values in concentrates. The 'A' type ore is a copper zinc ore with some silver and little lead. The 'C' type ore is a zinc silver ore with some lead and copper

Jan 1, 1981

By Isabel Ferreira de Barros

O objetivo deste trabalho é investigar o efeito da pulsação de corrente sobre a microestrutura da zona fundida de soldas dissimilares entre o aço inoxidável ferrítico AISI 444 e o austenítico AISI 316L. Chapas dos referidos aços foram unidas pelo processo de soldagem TIG. As soldagens foram realizadas variando-se a frequência de pulsação de 2 a 8 Hz e sem pulsação, mantendo-se constante a energia de soldagem. A caracterização microestrutural foi realizada por meio de microscopia óptica, MEV, EDS e EBSD. Os resultados mostraram haver um efeito da frequência de pulsação sobre a homogeneidade e microestrutura final da zona fundida.

Aug 7, 2018

By K. H. J. Clarke

SINCE the beginning of this century the non-ferrous mineral industry has contributed $17,809,-000,000 to the economic growth of Canada. To contemplate the vast amount of investment capital required and the resultant beneficial distribution of these billions of dollars for labour, transportation, supplies, taxes and dividends, challenges the imagination. It is the purpose of this paper, (a) to trace the development of the industry since its formative period to the present; (b) to discuss the current situation and problems; and ( c) to attempt to peer into the hazy future. Although there are 21 metals currently being produced in Canada which are classified as non-ferrous, or as alloying metals, copper, lead, zinc, nickel-the metals which will be discussed in this paper-constitute almost 60 per cent of their total value. ;The story

Jan 1, 1961

By D. Harrington

The number of fatalities from mine explosions for the fiscal year 1945 dropped below that of the year before; continued improvement over the record of the years from 1940 to 1945 is hopeful, but the number of reported explosions has increased rather than diminished, and the number of victims claimed by explosions is often more definitely a factor of chance than forethought. Mine fires and explosions can be eliminated through the methods now well-known to those well-informed in matters pertaining to safety in mining but ignored by many coal-mine operators and employees who follow procedures of the past or their own short cuts, regardless of disasters that may result: Tried and proved safety measures for preventing mine fires and explosions have been recommended to the mining public repeatedly, yet only a relatively small but far-sighted minority have adopted these measures and made them a part of operating practice. That far more explosion disasters did not occur in 1945 is fortunate. In 1945 a coal-mine fire of electrical origin caused heavy loss of life, while several others from the same cause were controlled with but few fatalities; this hazard is now being curbed temporarily to some degree after the bad record of the two preceding years, but a real solution of the problem has not been reached, although cooperating committees trying to produce at least some answer have made progress.

Jan 1, 1946

By C. R. DeGennaro, Yongjun Zhang, J. Bickson, J. L. Carr, Chenming Zhou, J. R. Srednicki, B. Lambie, M. Girman, J. A. Galanko

Between 2005 and 2021, surface mining haul trucks were involved in 54 fatal incidents in the United States [1]. Collision warning and avoidance systems (CXS) can help haul truck operators navigate their route safely. The evaluation of CXS object detection performance for surface mining haul trucks relies on the positional accuracy of the ground truth instrument. As part of a holistic approach, researchers from the National Institute for Occupational Safety and Health (NIOSH) characterized the accuracy of a global navigation satellite system (GNSS) that serves as the ground truth instrument to determine object position and velocity in CXS object detection performance testing. We used precision surveying equipment to establish ground truth points for comparison with GNSS data collected for static positional measurements and reduced-scale straightline vehicle dynamic tests. We conducted these tests with real-time kinematics (RTK) and then satellite-based augmentation systems (SBAS). For the dynamic tests, we measured a distance error of 1.34 m (4.40 ft) using RTK and 1.50 m (4.92 ft) using an SBAS. This research will provide CXS manufacturers and CXS researchers a basis for evaluating the positional accuracy of CXS. Note that we did not evaluate any CXS in this experiment.

Feb 1, 2024

By Deverux M

Heavy mineral deposits accumulate on shorelines with interrupted sediment input. Beach deposits, which form on shallowly dipping coastal plains, are most favourable. However, shallow shelves seaward of cliffed coastlines are known to contain economic deposits. Significantgeologicalconditions are defined, from review of the stratigraphic and geomorphic controls on known deposits , for heavy mineral accumulation on the Swan Coastal Plain.

Jan 1, 1986

By Leonardo Massone

The p-y method is one of the most popular methods in pile design and has been calibrated for various boundary conditions using numerical and experimental studies during recent years. Most studies on reinforced concrete (RC) piles have included the impact of flexural nonlinearity, (e.g. nonlinear moment?curvature relations) but not considered associated pile shear deformations when deriving p-y curves from field data. Common p-y curves may be better applicable for piles with flexure dominated failures (e.g. piles with free- head boundary conditions). For piles with fixed head boundaries (i.e. rotation restrained piles) shear deformations could be of significant influence. To study this problem, a coupled shear flexure interaction model for axial-bending-shear behavior coded in OpenSees is applied to a 0.61 m flagpole and a 0.61m fixed head pile specimen to investigate the possible influence of shear deformations to the overall pile responses. The surrounding soil is represented by p-y curves derived from prior large scale testing on piles with similar boundary conditions. Analysis results show that for flagpole piles, shear forces and shear deformations were insignificant. Considerable contributions of pile shear displacements and forces were observed for the fixed head pile, with shear displacements contributing up to 40% of the total pile displacement. Results suggest that nonlinear shear deformations for reinforced concrete piles should be considered for fixed-head or similar conditions, and that currently used p-y curves may underestimate the actual lateral pile displacement and possibly lead to unsafe design for the particular boundary condition.

Jan 1, 2011

By B. W. Gandrud

This report, consisting mostly of float-and-sink data and washability curves, has been prepared in connection with an exhaustive study of coal preparation in Alabama conducted, by the U, S. Bureau of Mines and the University of Alabama with the cooperation of the different coal operators On the basis of the float-and-sink data, an attempt has been made to determine approximately the extent of ash and sulphur reduction obtainable under given conditions on coal from the mines which were sampled, In the coal-producing districts of Alabama a great deaf of attention has been given in recent years to the problem of improving preparation methods so as to obtain from various coal beds the best possible grade of washed coal. This is especially so where the washed coal is used for the making of metallurgical coke in by-product plants or where there are possibilities of using the coal for this purpose. In the manufacture of metallurgical coke, the sulphur content of the coal is a very important consideration. It is quite often the determining factor as to whether or not a certain coal can be used for coke making. In the studies which form the basis for this report, all samples have been analyzed for sulphur in order to obtain information regarding the possibilities of sulphur elimination as well as ash reduction, and the samples on which reports are made were obtained from beds that are characterized by rather high percentages of sulphur. In connection with the present investigations of coal preparation in Alabama a standardized method of interpreting float-and-sink data has been used extensively for predicting the ash and sulphur reduction and yields obtainable in a commercial washing plant from various sizes of raw coal and from the raw coal as a whole after a certain degree of crushing. This method, which will be explained in subsequent chapters, was used in interpreting the data contained in this report. The samples used for these washability studies were obtained from the following mines in the Warrior field of Alabama: Beltona mine on the Jefferson bed; Dolomite and Mulga mines on the Pratt bed; Coal Valley No. 163 and Coal Valley No. 11 mines on the Corona bed; Cedar Cove mine on the Carter bed.

Jan 1, 1932

By B. W. Candrud

This report, consisting mostly of float-and-sink data and washability curves, has been prepared in connection with an exhaustive study of coal preparation in Alabama conducted by the U. S. Bureau of Mines and the University of Alabama with the cooperation of the different coal operators on the basis of the float-and-sink data, an attempt has been made to deter-mine approximately the extent of ash and sulphur reduction obtainable under given conditions on coal from the mines which were sampled. In the coal-producing districts of Alabama a great deal of attention has been given in recent years to the problem of improving preparation methods so as to obtain from various coal beds the best possible grade of washed coal. This is especially so where the washed coal is used for the making of metallurgical coke in by-product plants or where there are possibilities of using the coal for this purpose. In the manufacture of metallurgical coke, the sulphur content of the coal is a very important consideration. It is quite often the determining factor as to whether or not a certain coal can be used for coke making. In the studies which form the basis for this report, all samples have been analyzed for sulphur in order to obtain information regarding the possibilities of sulphur elimination as well as ash reduction, and the samples on which reports are made were obtained from beds that are characterized by rather high percentages of sulphur. In connection with the present investigations of coal preparation in Alabama a standardized method of interpreting float-and-sink data has been used extensively for predicting the ash and sulphur reduction and yields obtainable in a commercial washing plant from various sizes of raw coal and from the raw coal as a whole after a certain degree of crushing. This method, which will be explained in subsequent chapters, was used in interpreting the data contained in this report. The samples used for these washability studies were obtained from the following mines in the Warrior field of Alabama: Beltona mine on the Jefferson bed; Dolomite and Mulga mines on the Pratt bed; Coal Valley No. 16B and Coal Valley No. 11 mines on the Corona bed; Cedar Cove mine on the Carter bed.

Jan 1, 1932

By Luis Angel De Montreuil

Ante el problema del tratamiento de minerales complejos, la demanda de eficiencia metalúrgica y bajos costos de operación, el ingeniero busca el apoyo de la mineragrafía como estudio microscópico de los minerales económicos. En ese sentido, el presente texto señala la importancia de la minegrafía -en tanto ayuda a la flotación de los sulfuros valiosos de los yacimientos peruanos. Asimismo determina las propiedades de los minerales con el fin de identificarlos.

Jan 1, 1986

By Guy Demers

"This paper defines the responsibilities and functions of the Maintenance Department, and its organization, physical and human assets, highlighting the unique operating problems. Due to the self-sufficient aspect of the Asbestos Hill Deception Bay project, the Maintenance Department cover-s fields that are numerous and very dissimilar: production, mobile, processing, service, power generation, fire protection, heating, water and sewage disposal equipment. Added to this, buildings, plant and camps, wharves and communications equipment all demand versatility, adaptability and expertise from maintenance personnel. Good maintenance practices are a necessity in this environment and are more critical than at southern locations; that is, high-quality replacement material, complete and well-controlled preventive maintenance, major repairs on a component-replacement basis, updated inventory, efficient training and permanent contacts with suppliers, combined with an equipment improvement program, updated specifications on lubricants, hoses, seals, filters, etc., are mandatory. The seasonal aspect of the operations applies a great deal of pressure on the maintenance team, as the production months do not permit major repairs. Short- and medium range planning and accurate evaluation of equipment conditions highly influence production efficiency. Maintenance control, planning and scheduling do not follow the accepted standard routines, as personnel turnover normally does not permit an accumulation of knowledge of the equipment history and condition by the •individual tradesman."

Jan 1, 1976

By Akshay Sakhuja, M. S. Karthika, R. Vignesh

"The bridge across River Mandovi in Goa is a cable stay bridge structure proposed parallel, along existing bridges for regulation and reduction of vehicular traffic; the entire bridge structure is supported on pile foundation socketed in rock. This paper describes drilling related issue encountered during execution of pile where bed rock varies considerably from factual geotechnical investigation, which in turn affected the productivity of bored piles socketed in rock then chiseling is advocated for rock socketing with limited number of blows based on penetration resistance of rock encountered or equivalent energy principle to increase the productivity and also to avoid excess chiseling which otherwise would have fractured the rock mass below and around the pile tip resulting in increased settlement of pile subjected to design load. Contractor decision on socket length have been taken without compromising either quality or productivity; the paper presents various procedures and the equipment involved for installation of pile in rock along with the conclusion related to termination of pile in rock and also the lessons learned in process.INTRODUCTIONPile foundations are generally used to transfer heavy loads in deeper bearing stratum if the soil immediately beneath the base of the foundation does not have sufficient capacity. The bridge across River Mandovi, Goa is in its construction phase as a part of the development plan of Goa State Infrastructure Development Corporation Ltd (GSIDC). The project was awarded to M/s. L&T Construction, Heavy Civil Infrastructure; subsequently the geotechnical investigation was awarded to M/s L&T Geostructures.The client has specified the foundation of the bridge as rock-socketed. Rock socketing is generally done to achieve higher bearing pressure through concrete-rock shear interface which many building codes permit. The design and construction of rock socketed pile foundation entails a detailed analysis and judgement on the superstructure loads, predominant geological conditions as well as ground water levels. The termination of pile is normally based on thumb rule of half to three times the pile diameter into the rock. Quite often the criteria is based on chisel penetration rate (Gandhi,1990) In fact, this is the key factor to consider appropriate and economical depth of embedment of pile into rock stratum which necessitates enormous understanding on the type and quality of rock strata encountered which may significantly influence the selection of suitable rotary rig for pile installation. Such criteria are site specific and also applicable for the set of equipment used for the particular project."

Jan 1, 2015

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

Ore samples from the South, Central and North ore-bodies of the King Cassilis Mine, near Omeo, Victoria, were broken and transported to Melbourne for experimental metallurgical treatment. A microscopical examination of individual unoxidised specimens, selected from these samples, was undertaken in order to thro'w as much light as possible on the occurrence of the gold which forms the valuable economic mineral in the ore.The following descriptions are the outcome' of this examination and show that very minute particles of free gold are mechanically associated with the sulphides. While the gold may be separated from the transparent gangue minerals by the flotation of the sulphides, the, actual size of the particles indicates that it is impossible to separate all the gold from the sulphides by grinding the ore to pass through a screen of 200 mesh in which the average width of the holes is 0.063 mm. Chemical disintegration of the sulphides is essential to free all the gold particles and render them available to the attack of chlorine or of a solvent.It is interesting to recall that a metallurgical investigation on the Cassilis ore in the same district by K. A. Mickle in...

Jan 1, 1933

By B Mohanty, D Zwaan

Systematic near-field vibration monitoring of stope blasts was carried out in a large, deep underground mine. A total of 31 production blasts were studied in order to investigate the effectiveness of existing blast designs. This involved the vertical retreat mining method, which requires drilling a raise bore or blasting a slot raise (typically 1.22 m in diameter) using large diameter boreholes (165 mm). The diagnostic technique employed multistation near-field monitoring of blasts with high-g (100 g) and high-frequency (>10 kHz) triaxial accelerometers. The amplitude of the vibrations is correlated with the strain energy transmitted from each explosive deck. The results showed that more than 30 per cent of the explosive decks contributed little energy to the rock breakage process in these blasts, and an equal number contributed only inadequately. These findings are indicative of serious blast malfunctions. The problems can be traced to inadequate deck blast design and possibly to drill hole deviation. The various causes for such malfunctions are discussed and remedial measures suggested.CITATION:Mohanty, B and Zwaan, D, 2015. Assessment of underground production blast designs and blasting performance, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 607–616 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015