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By W. H. Yong

The molybdenum ores currently utilized in China are mostly molybdenum sulfide ores, whereas oxidized molybdenum ores have not been exploited and utilized efficiently. The aim of this article is to study the applied mineralogy of an intergrown iron-molybdenum oxidized ore in order to provide a mineralogical basis for the ore beneficiation research. The ore occurred in a surface oxidized zone seam and contained 23.65% Fe2O3 and 1.58% Mo. Various characterization techniques were employed to study the chemical composition and mineral composition of the ore, the particle size distribution of the minerals in the ore, and the tex-ture and structure of the ore. The results showed that the iron-molybdenum ore occurred in a wet, soft and earthy state. The ore was composed mainly of several oxidized minerals and colloidal min-erals, including wulfenite, barite, limonite and quartz. Wulfenite was one of the major and stable components in the ore and occurred as a separate mineral. Wulfenite, barite and quartz were granu-lar minerals with particle size ranging from fine to coarse but mainly in the fine particle range. Li-monite showed a crust and honeycomb-like colloidal state and composed the framework in the ore for the formation of the other minerals. They filled the pores in the framework and the size of the pores affected the size of the minerals formed in the pores and hence the recovery of wulfenite in ore beneficiation. According to the applied mineralogical properties of the oxidized molybdenum ore, a promising ore beneficiation process was proposed as follow Magnetic separation should be carried out first to separate the magnetic iron minerals and then the molybdenum mineral will be recovered by gravity concentration or a combination process of gravity concentration and flotation, depending on the distribution of the molybdenum mineral in the product of the magnetic separation.

Jan 1, 2014

By Coombes J, Richards W. L

The objective of this paper is to illustrate, in a practical way, how both geologists and mining engineers can use conditional simulation to add value to their decisions. Inherent assumptions, requirements and essential components of condition

Jan 1, 1998

By C. A. Herbert

Information Circular 6746 reviewed the fatalities in Indiana coal mines. for the fiscal year October 1, 1951 to September 30, 1933. Since then Indiana has changed its fiscal year to the period July 1 to June 30, but as most statistical data on accidents are arranged according to calendar years, the data in this paper are for the last 3 months of 1932 and the calendar year 1933, rather than for the new Indiana fiscal year. Tables 1 and 2 list the fatalities in Indiana coal mines3/ by cause and occupation for the last 3 months of 1932 and for the calendar year 1933. The fatalities for the small wagon mines employing fewer than 10 men are separated from those employing 10 or more men to call attention to the ex- tremely high fatality rate in small mines, largely because the State mining law does not apply to them nor do they come under the jurisdiction of the Indiana mine inspectors; as a result health and safety conditions are ex- tremely bad. During the last 3 months of 1932, 5 (approximately 42 percent of the total) fatalities occurred in the small mines, while for the calendar year 1933, 12 (approximately 32 percent) of the fatalities occurred in them. The Indiana Division of Mines and Kining estimates that these small mines have an annual production of approximately 325,000 tons, or about 4.5 percent of the total coal-mine production of the State. In other words, for these small mines the fatality rate per tons mined during 1933 was about 10 times as great as for the mines employing 10 or more men. Another lamentable feature in connection with the fatalities in small mines is that very few carry any compensation insurance and the owners are not worth enough financially for dependents of victims to collect anything under the common law; as a result, the dependents of those killed usually are left penniless and subjects of public charity.

Feb 1, 1935

By J. J. Shields

This is the Seventh of a series of publications that describe methods and practices used in mining bituminous coal mechanically.3/ This report deals with the operation referred to in coal mining as continuous mining, and the interest shown by mining companies in this method is the reason for this study. Only continuous mining as it applies to the room-and-pillar system of mining, or a modification thereon, is discussed in detail in this report. Although not always as continuous as the name implies, it is a system of mining in which a machine is used to cut and load coal in one continuous operation without drilling and blasting the coal. With the mining equipment in most general use today, the usual cycle of operation in mining of coal is: (1) Timber, (2) cut, (3) drill, (4) blast, and (5) load. As the phases of this type cycle cannot be performed simultaneously in the same working place, it is necessary to operate from 3 to 7 working places so that at least 1 place is available for coal loading at all times. Even if the schedule of the phases in a cycle is maintained, coal production ceases during the time required to move the loading equipment from one loading place to the next. In 1920 a continuous-type mining machine4/ was installed in an Illinois coal mine to drive entries. Several other companies used these entry drivers for short periods in the following few years. In 1927 a southern Illinois coal company installed 2 of these machines which, in the next 25 years, were reported to have driven over 200 miles of entries. The machines did not attain widespread usage.

Jan 1, 1954

By N S. Weerasekara, S Town, E Lessing, J A. De Torres

Philsaga Mining Corporation (Philsaga) had three main aims in converting their lining system from steel to metal cap. They wanted to increase mill availability, minimise localised high wear and optimise particle breakage to deliver increased efficiency within the milling circuit. Combining Discrete Element Method (DEM) modelling and empirical interpretation of liner wear resulted in a rigorous approach to understanding the impact of mill liners on overall mill performance. This new understanding was subsequently used to not only derive a new lining design to optimise performance and thereby improve overall plant economics, but also to guide further lining development.In this work, detailed DEM modelling, developed from actual plant data, together with optimising liner design for wear paved the way towards the installation of a Metal Cap lining system at Philsaga’s Ø6100 mm SAG Mill. The results were a reported increase in SAG mill throughput of 16 – 20 per cent due to improved breakage through more efficient use of installed power, a reduction in localised high liner wear with overall increase in liner life and reduction in liner replacement time. Site also reported an increased gold recovery of 2 per cent which the improved breakage might have contributed to. This paper will present the design challenges and compare the Metal Cap lining systems performance against Steel lining system. CITATION:Weerasekara, N S, Lessing, E, Town, S and De Torres, J A, 2018. Metal cap versus steel lining system at Philsaga Mining Corporation’s Ø6100 mm SAG mill, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 653–664 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Joseph A. Dos Santos

The largest TBM (Tunnel Boring Machine) tunnels are typically along modest slopes, but not always. Occasionally high slope angles are required beyond the capabilities of conventional open trough trailing conveyors. A 2019 project required a large TBM to ascend to an incline angle of 25°. A Sandwich Belt high angle conveyor could easily solve the high angle conveying problem but such a system must include all of the features of the conventional trailing conveyor, particularly the ability to extend with the TBM advance. The writer responded to the challenge and developed a TBM trailing Sandwich Belt high angle conveyor with all of the needed features. The invention (U.S.A. patents awarded October, 2021 and November, 2022) however goes beyond the 2019 project requirements and extends to any high angle incline. This writing first presents the broad Sandwich Belt high angle conveyor development, then its use in various construction and tunneling projects prior to this TBM Sandwich Belt trailing conveyor invention. Finally we present the new TBM Trailing Sandwich Belt high angle conveyor with all of its features and implications.

Jun 13, 2023

Drag pick roadheaders and continuous miners have been applied in the coal mining industry for several decades, having replaced drill-blast methods as the primary means of excavating coal and coal-measures strata. The generally harder rock types associated with metalliferous mining have precluded the use of such machines in the past, however, developments in machine technology and increasing labour costs and environmental constraints suggest that there are now likely to be applications suited to the method. Metalliferous mining engineers are generally unfamiliar with the machines themselves and with the fundamental criteria controlling rock cuttability. This paper gives an introduction to the machines and the controlling factors.

Jan 1, 1987

By Chugh Y. P

A generalized void diffusion model for subsidence prediction has been developed based on theoretical concepts and physical principles. The general form of the model is a three-dimensional differential equation. With a few assumptions on the characteristics of overburden strata overlying typical room-and-pillar mining or longwall mining systems, specific solutions for the differential equation were obtained. A brief description of these solutions and their applications in the United States and China are presented in this paper.

Jan 1, 1992

By Snehamoy Chatterjee, Sanjay Kumar Palei, Smarak Das

Machine manufacturers’ recommendations on maintenance strategies of capital-intensive draglines are not always based on real data and therefore lead to losses from downtime. This paper proposes a preventive maintenance strategy for a dragline deployed in an opencast coal mine based on reliability-centered maintenance and failure-mode-effects analysis using real operational data. Reliability-centered maintenance replaced a cluster of critical failure components of the dragline while satisfying two specific conditions: (i) the components should be replaced at the earliest mean time to failure (MTTF) within the group and (ii) the time taken to replace all the parts should be equivalent to the maximum downtime within the group. Estimated threshold weightage factor identified twenty-six critical failure components for the preventive maintenance strategy, and clustering of components divided them into nine groups. In a group, the loss that is expected to occur by replacing some of the components before their failure, and the gain by reducing the overall maintenance downtime, has been explained through a cost-benefit analysis. The total net profit generated is calculated as US$200,178. This clustering activity also led to a reduction of annual downtime by 231 h, whose approximate market price as equivalent coal production costs $295,365.

May 28, 2020

A PRELIMINARY PROGRAM, dated April 25, 1974, was prepared for Development Engineering, Incorporated (DEI) on research and development laboratory, field and other engineering studies for the disposal of retorted oil-shale materials. This PRELIMINARY PROGRAM included a discussion on the peculiarities of the retorted shale materials to be investigated and a discussion of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The PRELIMINARY PROGRAM was divided into eight work phases as follows: I -- Program Development II -- Exploratory laboratory tests on old USBM retorted shale III -- Laboratory tests on pilot plant retorted shale. IV -- Laboratory tests on retorted shale from the semi-works plant and field test plots and ponds. V -- Field compaction tests. VI -- Infiltration pond tests VII -- Bureau of Mines special tests.

Jan 1, 1975

By Jean-François Boulanger

The production of rare earth elements from ore usually consists of three steps; the separation of a concentrate of REE bearing minerals; the cracking of the REE minerals to liberate the REE into an aqueous solution and separation of REE into individual elements. This paper describes the results of laboratory tests conducted on a carbonate-rich REE ore containing bastnaesite and monazite. The tests cover the whole processing sequence of beneficiation, preparation of the REE solution using a caustic leach followed by acid leach to break monazite and bastnaesite and liberate REE into an aqueous solution and the partial separation of the REE using solvent extraction. Details on the product quality and process performances (recovery and impurities removal) are given for each studied step. The paper also discusses the economic advantage of separating the REE rather than producing a mixed REO product to be sold to a refinery for REE separation. A mini-pilot plant version of the process is currently planned.

By K. A. Clark

"The repacked mineral aggregates of good grade oil sands have permeabilities ranging between 15 darcys to 350 millidarcys. The variation is due to the silt contents of the aggregates. Few good grade oil sands contain as much as 30 per cent •silt, most of them contain less than 20 per cent, and a large proportion have less than 10 per cent.The permeabilities of repacked good grade oil sands (oil included) depend on the degree of liquid saturation. When saturation with oil plus water reaches between 80-90 per cent, permeability is reduced to zero. As total saturation decreases below 80 per cent, permeability increases ranidly. Permeabilities of between one and two darcys were observed for total saturations between 60-70 per cent.The mean value for 18 measurements of the permeabilities of ""undisturbed"" core samples of good grade oil sands was 50 millidarcys. This value is •probably too high. The mean value for 20 measurements on core samples of interbedded oil sand and shale was 100 millidarcys. The mean value for 11 measurements on shale was 10 millidarcys."

Jan 1, 1960

By Jogeshwara Sahu, Sapan Kumar Kandi, SANDEEP KUMAR JENA, Sachida Nanda Sahu, Sarada Prasad Das

The present article reports the recovery of potassium from mica scrap using carbide lime waste and NaCl. The acid leaching of mica [4 M H2SO4 at 90 °C] can recover a maximum of 25% potassium. However, in the chlorination roasting (with CLW and NaCl) water leaching process, it was possible to recover potassium to the tune of 94% [900 °C, 50 min roasting; mica:CLW:NaCl 1:0.75:1]. The formation of water-soluble phase like sylvite (KCl) and water-insoluble phases like anorthite ( CaAl2Si2O8) and nepheline ( NaAlSiO4) confirms the complete breakdown of the mica crystal structure. The extraction mechanism proceeds with the formation of a transition state followed by the release of potassium as KCl. The characterisation studies using ICP-OES, XRD, FTIR and FESEM support the proposed extraction mechanism. The salt produced by the evaporation of roast-leached liquor confirms the presence of sylvite and halite only, which can be separated to get the fertiliser grade KCl.

Sep 29, 2021

By J. U. MacEwan

THE basis on which the modern metallurgical industry is operated is the endeavour to attain maximum return in purchasing power for the least expenditure of energy. This has always been the general objective of the industry, as of all industries. In recent years, however, it has received a new emphasis. Today, as never before, increased attention is being directed to the detailed study of plant operations and the application of scientific knowledge and of business principles in order to achieve the maximum efficiency. This new emphasis is the result in large part of the new problems and conditions with which the industry has been confronted, chief among which are the following: (l) Development of new ore-bodies and the treatment of complex ores. (2) Necessity of achieving a greater degree of purity in some of the metals in order to meet the newly discovered demands for some of the industrial metals. (3) Discovery of new markets for many of the metals, either in pure form or in the form of alloys. ( 4) Change in values, absolute or relative, of some of the important metals. (5) Increasing scale of investment in expensive plant and equipment, which makes imperative most efficient utilization if total unit costs are to be kept to a minimum. (6) Increasing scale of operations in some important branches of the industry, which also makes essential maximum efficiency in organization, administration, and operation. The success with which the metallurgical industry has met the problems created by these changing conditions has been due primarily to the following factors: (1) Results of research and experimental work carried on by universities, government laboratories, and many private corporations in the industry itself. (2) Closet study of every detail of plant operation, both from the technological and from the economic point of view, with the object of increasing plant efficiency. (3) Interchange of information and experience amongst the operating companies. It is only by the concerted efforts of numerous investigators and experimenters that the underlying fundamentals of plant operations can be learned. The exchange of results permits their easy assembly and correlation with maximum benefit to the whole industry. Unnecessary duplication of research and experimental work is avoided and the industry as a whole is able to reap the fruits of this work with the maximum of-speed and efficiency. (4) Advances made in recent years in so-called 'scientific management' in industry as a whole and the application of the principles learned to the metallurgical industry. A review of the modern trends in extractive non-ferrous metallurgical processes illustrates the afore-mentioned new conditions and problems, and gives some idea of the methods by which they have been and are being surmounted.

Jan 1, 1937

By C. W. Pritchett

Several years ago, during a trip from Jojutla to Huauatla, in the abate of Morelos, Mexico, I was told by my guide of the ruins of an old smelter near by, and my curiosity was excited to such an extent that I went out of my way several miles to see them. I found them very interesting; and, as I fortunately

Jan 1, 1902

In order to satisfy environmental and mine operational requirements it is becoming increasingly important to minimise ground blast vibrations at certain locations. These locations are often in soil or on large resonant structures such as grain silos, highway bridges or even the walls of an open pit. A soil monitoring exercise was carried out to evaluate the common practice of coupling vibration detectors to the ground using spikes. At a series of locations in an operating quarry the spiked array response to single blastholes was compared with that of an accelerometer array attached to a calibrated embedded mount. The results clearly showed that the spiked arrays over-estimated the true ground vibration by 46.5 per cent on average, with a maximum observed error of 99.2 per cent. These errors are considered too large for compliance monitoring where accurate vibration levels are required for comparison with prescribed limits. Although spike coupling is convenient, its use for compliance monitoring should be viewed with caution. Unfortunately, however, many manufacturers supply their detectors as spiked arrays. A structural monitoring exercise was also carried out to evaluate the vibration response of a grain silo, highway bridge and a pit wall to the initiation of single blastholes. In this case accelerometers and standard geophones were firmly attached to the bridge which resonated at low frequencies. The results clearly show that, due to their limited low-frequency response, the geophones typically measured only half the true vibration level as measured by the accelerometers.

Jan 1, 1995

By Chris Strawson

Moranbah North is a modern longwall operation mining premium coking coal in the Northern Bowen Basin, Central Queensland. Australia Moranbah North Coal (MNC) is owned and operated by Anglo Coal Australia. Extracting approximately 4.5m of the Goonyella Middle seam using a single longwall, the mine produces 5 to 6 Mt per annum. The weak coal (4.5 MPa), low strength laminated immediate roof, and strong upper roof sandstones, make operation of the longwall at depths in excess of 250m geotechnically challenging. In the past, there have been a number of production delays due to geotechnical issues. Roof instability resulted in a long stoppage on Longwall 105, and the eventual relocation of the face further outbye in the block. (Figure 1). When mining commenced in LW106, there was a requirement for uninterrupted production, particularly in the more demanding inbye area of the panel. Following discussions with a number of Geotechnical experts, it was decided to narrow the face, and test the theories of reduced face weighting due to spanning of the goaf across the panel. A new on line chock monitoring system, and microseismic monitoring was installed in order to characterise the difference in the rockmass response, as the panel width changed from 175m, to 265m, and then 300m. The nature of the goaf formation and impacts on face loading and production are discussed, having the unique opportunity of three different face widths within the same area.

Jan 1, 2007

By Georges Delemontex, Nigel Grigg

"Pre-concentration of precious metal and base metal ore types is becoming more relevant with the discovery, development and operation of many lower grade deposits around the world. The fluctuations in metal prices and currencies expose many mines to risks especially dealing with low and variable ore grades. Pre-concentration, the process of concentrating the valuable metal into a smaller mass yield, effectively results in the introduction of higher feed grades to milling circuits. Gangue rejection, the removal of lower S.G. waste rock from the circuit, not only results in higher downstream grades but also potentially removes harder, non-valuable mineral, providing significant power savings within the circuit. The pre-concentration or ‘gangue rejection’ process offers a number of benefits when considering the treatment of marginal ore deposits, especially if it can be performed at a coarse crush size; these benefits include a reduction of the operating costs and the feed of more metal units to the mill. Gekko Systems has effectively utilized the Inline Pressure Jig (IPJ) to pre-concentrate the valuable metal, achieving high primary recoveries into a range of mass yields resulting in upgrade ratios between 2 and 10 times. This paper explores: the benefits of pre-concentrating ‘marginal’ ore deposits prior to the milling circuit; the selective rejection of ore types that may affect either the recovery or comminution process; and also looks into the potential to effectively reduce the ‘cut-off’ grade when considering the mine planning process. Case studies of projects using the IPJ to pre-concentrate and reject gangue are also included. Pre-concentration and gangue rejection provide the potential to develop marginal ore deposits, thus providing higher grades, less gangue and more metal at a lower operating cost to producers."

Jan 1, 2014

By Z. Hyder, A. Urquidez

"INTRODUCTION The Waste Isolation Pilot Plant (WIPP) is located approximately 26 miles southeast of Carlsbad, New Mexico and is the nation’s first underground geologic repository for transuranic (TRU) and TRU-mixed waste (see Figure 1). The WIPP facility was opened for operation in 1999 when the first TRU waste shipment arrived at the WIPP facility for disposal.WIPP facility does not employ typical production aspects of a conventional mine. Instead, the mining focus is on the quality of the excavation to ensure safe disposal of TRU and TRU-mixed waste (Walls, 1991). GEOLOGY WIPP underground repository is mined within a 2,000 feet-thick bedded-halite formation (Salado Formation) (see Figure 2). The WIPP underground repository is located approximately 2,150 feet beneath the surface near the center of the Salado Formation. Geologic criterion and site-selection factors evaluated for the selection of the repository included topography, depth, thickness, lateral extent, lithology, stratigraphy, structure, erosion, dissolution, subsidence, surface water, aquifers, hydrologic transport, climatic fluctuations, manmade penetrations (U.S. Department of Energy, 1980).FACILITY DESIGN Profit did not play a major role in the WIPP’s conception like in a conventional mine. This was due to the extensive amount of additional regulations and safety controls that had to be built into the WIPP facility. Since it is nuclear and hazardous waste disposal facility, it must meet certain federal and state requirements for TRU-mixed waste. One of the major regulatory drivers for the WIPP facility is defined in the WIPP Land Withdrawal Act (LWA). One of the requirements in the WIPP LWA requires the DOE to submit documentation of continued compliance with Title 40 CFR Part 191, Subparts B, and C. These standards are regulated by the Environmental Protection Agency (EPA). The DOE must submit documentation of continued compliance (recertification) with these regulations every five years. In addition to the LWA, the Resource Conservation and Recovery Act (RCRA) is another major regulatory driver for the WIPP facility. Since the WIPP facility is categorized as a “Miscellaneous Unit” under 40 CFR, it must meet extensive environmental performance standards. These standards are defined in the WIPP Hazardous Waste Facility Permit (HWFP). The HWFP defines the terms and conditions that the Secretary of the New Mexico Environment Department has determined necessary to protect human health and the environment (U.S. Department of Energy and Nuclear Waste Partnership LLC, 2015)."

Jan 1, 2017

By T. Ivankina, T. Lokajícek, H. Kern, T. Svitek

The knowledge of 3D velocity distribution of P- and S-waves in rocks is very important parameter for interpretation and understanding the nature of seismic anisotropy observed in the earth’s crust and upper mantle. A new high-pressure measuring head was designed and constructed to enable ultrasonic sounding of spherical rock samples in 132 independent directions under up to 60 MPa of acting hydrostatic pressure by means of simultaneous longitudinal and transversal sounding. New measuring system enables ultrasonic sounding of spherical rock samples by using a pair of P-wave sensors and two pairs of perpendicularly polarized S-wave sensors (TV and TH) see Fig.1. Shear wave sensors polarization is oriented according to rotation axis of the sample. Special shear wave gel was used to transfer shear waves between the sample and sensors under acting hydrostatic pressure. An isotropic glass sphere was used to check and calibrate the new measuring setup. A spherical sample of a biotite gneiss from the Outokumpu scientific drill hole was used for testing measurement. There is shown that both, P- and S-wave velocities, can be measured simultaneously up to 70 MPa, respectively. We report data of the 3D velocity distribution of P- and Swaves measured for the first time on a sample sphere of biotite gneiss. We rely, in particular, on the directional dependence of compressional and shear wave propagation and their relationship to the crystallographic (CPO) and shape preferred orientation (SPO) of major rock-forming minerals. The 3D seismic measurements revealed a strong foliation-related directional dependence (anisotropy) of P- and Swave velocities. Ultrasonic measurements were compared with 3D velocity calculations based on neutron diffraction measurements of crystallographic preferred orientation (CPO) of major minerals. Comparison of 3-D velocity distribution (P, S1, S2 and S1-S2) determined by two completely different methods ultrasonic sounding and neutron diffraction is presented. Measurements showed that the intrinsic bulk anisotropy is basically caused by the CPO of biotite constituting about 23 vol.% of the rock.

Jan 1, 2015