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In recent years, coal beneficiation has gotten considerable attention. Selective oil agglomeration has been accepted as the best method to produce clean coal with a high removal of pyrite sulphur. In this study, spherical oil agglomeration of Datong coal fines was carried out using diesel oil as a bridging liquid. The oil agglomeration has a surface properties based on coal cleaning technique. The effects of fundamental parameters have been investigated including the concentration of bridging liquid, the size of coal particle, the solid content of slurry, the agitation time and rate, pH, surfactants on the agglomeration performance and various salts on the ash rejection and removal of pyrite of the agglomerated products. The optimum conditions of particle size, diesel concentration, solid content, agitation speed and time, pH and the dosage of active agent have been determined as less than 8µm, 20wt%, 1200r/min and 10 minutes, 7.5g/t and 100g/t, respectively. Under these conditions the ash content in the products can be achieved 1.5% below, the ash rejection was up to 92%. It has been observed that ionic strength of the aqueous medium affects the agglomeration performance. The precombustion coal cleaning process based on improved selective agglomeration results in high ash and pyrite sulphur removals. Over 80% removal of pyrite sulphur can be achieved from run-of-mine coals by offering a more cost-effective sulphur reduction solution rather than any other SO2 removal technology. In addition, the removal of pyrite sulphur is very necessary for not only the prevention of environmental pollution but also economical reasons.

Jan 1, 2014

By Z. Cheng, Y. Han

"For non-sulphide minerals such as oxidized minerals, fluoride minerals, and oxysalt minerals, there are generality in the molecular structure of their floating collectors, and similarity in crystal structure of the minerals. In the paper, adsorbing mechanism of these collectors on the surface of these mineral particles in different pH pulp was investigated by means of Pauling's rules & valence bond theory, Valence-shell electron pair repulsion theory (VSEPR) theory, Crystal and ligand field theory, and quantum chemistry simulation by DMol3 and CASTEP modules of Material Studio software. Besides, the role and status of hydrogen bond in the floating adsorption mechanism were studied emphatically, and the confirmation and characterization of hydrogen bond were explored also based on the test results. What is more, the conclusion “the effect of hydrogen bond can not be overlooked in adsorbing mechanism of flotation collectors on the minerals” and a new viewpoint of multi-polarity collaboration and hydrogen bond coupling were summarized eventually based on analysis of the measurements. Finally, a novel collector 2-Amino-3-Methyl Heptyloxy-Propylamine (AMHP) was developed based on the new viewpoint of molecular structure design, and its collecting performance was exhibited.INTRODUCTIONWhen it comes to the recovery of flotation, it is necessary for researchers to investigate the flotation mechanism of collectors. In traditional theory, when collectors were used to collect minerals, the attractions between collectors and minerals were divided into chemical, electrostatic and physical attractions (Wills, B.A., 2006). Especially, because of the reaction between sulphide minerals and sulphydryl collectors is complex and various mechanism has been proposed (Yoon and Basilio, 1993), when collectors were used to collect non-sulfide minerals, it can be classified into oxyhydryl anionic collectors and cationic collectors. In traditional theory, the adsorption of oxyhydryl anionic collectors were due to water-repulsion, and the adsorption of cationic collectors were due to electrostatic attraction between the polar head of the collector and the charged electrical double layer on the mineral surface (Wills, B.A., 2006)."

Jan 1, 2018

By Anuttam Patra, Romain Bordes, Andreas Fredriksson, Tommy Karlkvist, Krister Holmberg, Kota Hanumantha Rao

The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying length between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant with the same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite and calcite mineral surfaces was studied using Hallimond tube flotation, FTIR and ? potential measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ? potential and infra-red spectroscopy data.

Jan 1, 2014

By H Kurth, L Balzan

On-belt analysers have been used since the early 1980s in the coal sector to measure ash content in real time for diverting material on conveyors to remove waste, bypass beneficiation and allow suitable material to proceed to the wash plant for processing. Since 2008, a GEOSCAN-M elemental analyser has been used on an overland conveyor in South Africa to divert direct-shipping quality iron ore to bypass a jig plant. This paper focusses on recent evaluation work to determine the suitability of an on-belt analyser to upgrade the processing plant feed in a copper-gold operation.Copper-gold ore samples from New Gold’s New Afton Mine near Kamloops, BC, Canada were tested to assess measurement accuracy over short time increments. A two-minute measurement increment has been used in the minerals sector as a compromise between good measurement accuracy and a useful tonnage (haul truck equivalent size or smaller). At New Afton, this increment represents approximately 35 t of material. Segregation decisions are currently made after visual and sometimes analytical determination, at increments of approximately 500 t to designate material as ore or waste at the drawbell in the cave.Results of test work including the composition range and expected accuracies by element are shown. The operation, which is not mine constrained, was evaluating the potential for ore upgrading through waste and low grade increment diversion to upgrade ore quality feeding the mill. Prompt-gamma neutron activation analysis (PGNAA) was considered as the company recognised that it would measure through the full conveyed cross section continuously and produce multi-elemental measurements unaffected by particle size, dust, moisture content, layering and segregation, mineralogy and belt speed.GEOSCAN analyses over various analysis periods will be collected to identify variability in the conveyed material quality and used to generate tonnage-grade curves so that an optimal diversion (bulk sorting) tonnage increment can be determined. Measurement increment time can be customised to suit site requirements. CITATION:Kurth, H and Balzan, L, 2017. Assessing bulk sorting suitability at the New Afton mine, in Proceedings MetPlant 2017, pp 315–323 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By John F. Oyler

The performance of high alumina refractory subjected to high compressive loads and high temperatures is an area in which operating experience is quite limited. This paper documents the results of five months of operation of a combustion chamber lined with 83 pct alumina brick subjected to compressive stresses as high as 45psi and hot face temperatures of about 2750°F. It also describes a method for predicting long term subsidence results based on the limited information available in standard hot load limit tests. Descriptions of the chamber itself and the pilot plant upon which its design was based are included.

Jan 1, 1978

By E. L. Litchfield

Spark ignition of combustible-gas mixtures is a relatively old subject of investigation and has been treated both experimentally and analytically by many people. Elements of static and current electricity are almost always present in mining and industrial operations, and the spark can be an extremely efficient source of ignition. Thus the practical interest of such problems as the "intrinsic safety" of electrical apparatus is obvious. Ignition and quenching phenomena are the primary laboratory representatives of combustion phenomena that are dynamically nonsteady, and such nonsteady phenomena playa considerable part both in industrial processes and in safety matters, although they are of less immediate practical interest. Considerable effort has been expended by the Federal Bureau of Mines in investigations of spark ignition.5 6 7 8/ Primarily, this work has established the significance of several of the parameters involved. Although the

Jan 1, 1959

By I Ritchie, A Johnston, D Yataco

Marcobre SAC (Marcobre) is developing the Mina Justa copper mine project, located in the Ica region of Peru. The Mina Justa IOCG orebody comprises of a sulfide mass overlain by an oxide cap with a sharp transitional zone between the sulfide and oxide masses. The primary target metal is copper, but there are minor amounts of gold and silver. The oxide will be treated by HPGR, crushing and vat leaching, whereas the sulfide will be treated by HPGR, milling and froth flotation. The processing selections are due to some unusual ore characteristics which have required relatively unconventional solutions.Vat leaching was chosen over heap leaching and other processes after detailed trade-off studies found it to be the most attractive, primarily due to the high acid consumption of the ore. The sulfide flotation produces a wide range of concentrate grades due to the complex nature of the mineralogy. The selection of HPGR circuits for both the oxide and sulfide ore is due to the extremely hard and competent nature of the deposit. These factors and others have contributed to a unique process selection for this resource.The selection process for the oxide and sulfide ores, and an overview of the technology, equipment selection and geometallurgy, will be discussed.CITATION:Johnston, A, Ritchie, I and Yataco, D, 2017. Process development for the Mina Justa project, in Proceedings MetPlant 2017, pp 207–217 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By T. M. Yegulalp

A new explanation of the scale dependency of the strength properties of rock is presented based on the theory of extremes. A review of past work on specimen size strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect on the statistical properties of the strength distribution. It is shown that the weakest link theory is directly related to extremal statistics and properties of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1992

By S. A. Vorobyev, Yu. L. Mikhlin, Ye. V. Tomashevich, A. A. Karacharov, M. N. Likhatski1, A. S. Romanchenko, S. V. Saikova

"A set of state-of-the-art methods have been applied to study ultrafine particles and nanoscale species arising on mineral surfaces upon milling, interaction with flotation reagents, and leaching of base metal sulfide ores in order to gain insights into interfacial mechanisms. The fine fractions produced by ball milling of a Pb-Zn Gorevsky ore and four Cu-Ni sulfide ores studied with laser diffraction, dynamic light scattering, zeta-potential measurement, Xray photoelectron spectroscopy (XPS), SEM, TEM and other techniques. The particle size distributions had, aside from the peaks at 20-60 ?m, maxima near 1-2 ?m; the flotation was considerably suppressed when the yield of positively charged ultrafine particles approached tenths % (several kg per ton). High-energy XPS and X-ray absorption spectra revealed that sulfide minerals depleted in metal in air and aqueous solutions were composed of outer “polysulfide” layers, strata with disulfide species, and heavily defective underlayers, and “passivation” was explained by stability of the metal-deficit structures. Dixanthogen at pyrite and copper-activated sphalerite, dixanthogen and then cuprous xanthate on chalcopyrite, and chemisorbed xanthate at galena were specified as the main interfacial products using cryo-XPS of fast-frozen flotation slurries. The particle size, zeta-potential and behavior of colloids of Cu and Pb xanthates and dixanthogens were largely determined by the initial ratio of a cation and collector; the properties of copper xanthate nanoparticles were also affected by incorporated dixanthogen (about 15 wt.%). Submicrometer gas domains of 3-8 nm in height and “hydrophobic” forces upon the probe retraction were found on xanthate-treated minerals using atomic force microscopy and spectroscopy; their impact on flotation is briefly discussed.INTRODUCTIONInterfacial phenomena play a key role in flotation, leaching, water purification and related environmental processes. The mineral processing and extraction of metal from sulfide ores commonly involves milling the ore, which produces, along with the particles of 20 µm to 100 µm, mineral entities ranging from micrometer to submicrometer and nanometer scale. Furthermore, ultrafine particles of flotation reagents, products of metal sulfide oxidation, and so on may form spontaneously and accumulate in production water, flotation froth, deposit on mineral surfaces, affecting the flotation performance, and then enter waste waters, mine and natural drainage, polluting soils, surface- and ground waters (Miettinen et al., 2010; Wang et al., 2014). The efficiency of flotation and hydrometallurgical recovery of values, environmental issues are crucially dependent on the state of mineral surfaces. Particularly, it is generally accepted that the surface non-stoichiometry of sulfide minerals induced by oxidation and leaching should affect their hydrophobicity and reactivity, including so-called “passivation”, but the nature of such surface layers are still a matter of controversy (see, for example, Holmes and Crundwell, 2013). Another phenomenon attracting rapidly growing interest in several areas is low-dimensional gas species (“nanobubbles”) at hydrophobic surfaces that may play a decisive role in particle-bubble attachment in flotation but remains scarcely investigated up to now (Xing et al., 2017). Here, we survey our recent results on the abovementioned problems applying a series of rather new methods and approaches; more details can be found in refs. Karacharov et al., 2016; Mikhlin et al., 2015; 2016; 2016a; 2016b; 2016c; 2016d; 2017; 2017a; Vorobyev et al., 2017."

Jan 1, 2018

By William J. Douglas

Critical path modeling (CPM) has been used widely as a tool to manage large-scale projects having many activities which are conducted in series or parallel. The construction industry is a regular user of critical path modeling as a planning tool. In this context, the method is used to provide an orderly schedule for all activities to forecast delays, slippages, and problem areas and to identify critical activities where resources should be directed. It also identifies others which have slack time, and provides information on the degrees of freedom and flexibility available in completing the project. The purpose of applying critical path modeling to an underground mining system is not primarily for scheduling, but as an analysis tool. In observing underground mining systems, it Is clear that repeated sequences of activities must take place for mining to proceed efficiently. Some of these activities must be sequential, while others be carried out in parallel. The fundamental difference between critical path modeling applied to mining versus a large-scale construction project are: (1) The activities in a mining system are cyclic in nature. (2) The location of the activity varies, and the entire process is not thought of as co-located, as is the case in a construction project. Another important aspect of the network development for mining systems is the degree of detail that is desired. One can be concerned with very macroscopic networks which represent, for example, an entire mine life cycle. Networks representing this problem would be more closely analogous to those of a large construction project. On the other hand, one might be interested in evaluating alternative ways of developing a property or of mining in a given section. More detailed networks representing the section activities are necessary to evaluate system parameters and their impact on long-term production.

Jan 1, 1978

By Yi Zheng

Under normal circumstances, methane released along a longwall face represents only 10%-20% of the total me- thane emitted from the entire longwall panel. However, there might be a sudden surge of methane at the face which may cause a potential problem because the friction from shearer cutting, support movement, and scraper conveyor dragging can be ready ignition sources. Therefore, to predict the distribution of methane will be critical to prevent possible explosions. In this paper, methane dispersion patterns along a lognwall face are simulated under normal and abnormal conditions. With the simulation of methane released from the face, around shearer drum, and from the broken coal on the conveyor, places with possible high methane content can be identified by different phases of working process and shearer positions. Local ventilation measures are evaluated so precautionary measures can be planned ahead.

Jan 1, 2012

By J. A. Hansuld

"THIS SESSION marks something of a milestone in that it is, as far as I know, the first session at a CIM Annual Meeting devoted entirely to exploration geochemistry. This is an indication of the general acceptance and widespread recognition by industry of geochemistry in mineral exploration. As a first, I hope it proves sufficiently successful and interesting that geochemical exploration sessions will become a routine part of future CIM annual meetings. The greater use and acceptance of geochemistry has resulted in many investigations and advances, especially in areas such as the Canadian Shield. For a first session on geochemistry, the meeting in Quebec suggested an ideal opportunity to assess these advances and report on the current application of geochemistry in the Shield. The theme of the session is ""Geochemical Exploration in the Canadian Shield - The State of the Art."" A series of six papers will be presented dealing with the various dispersion media - rocks, heavy minerals, ""soils"", lake sediments, waters and vegetation. As a background to the individual presentations, I would like to take a few minutes to briefly trace the history of the use of geochemistry in the Canadian Shield."

Jan 1, 1971

By S. Benedict Levin

In the spring of 1944, during the emergency In the supply of strategic mica, the Bureau core-drilled six aggregating 913 feet, at the Blister mica Trim. Cheshire County, N.H. These holes indicated a downward extension or the mica shoot which was being mined at that time and developed information essential for economic mining of the deposit.

Jan 1, 1949

By M. Howard Berliner

"INTRODUCTION During the last 4 months of 1943, the Bureau of Mines engaged in an investigation and exploratory drilling program in the area between the Coughlin and Galena Level mines near the town of Shullsburg, in Lafayette County, Wisconsin. The work was undertaken as part of a general Bureau of Mines investigation of the zinc-producing area of southwestern Wiscon¬sin at a time when an effort was being made to increase the production of metals important to the Nation's war program.The portion of the southwest Wisconsin zinc district in the immediate vicinity of Shullsburg and the Coughlin and Galena Level mines is well mineralized. The principal ore horizon is at shallow depth, and there is evidence that relatively extensive surface mining for lead was done over a period of many years. Underground mining' for lead and zinc has continued to the present time.The Bureau undertook an exploratory drilling program in the area immediately west and southwest of the Coughlin mine workings after thorough preliminary investigations and geologic studies indicated that such work would serve to guide operators in the development of new ore reserves needed for continuance of mining operations in that area."

Apr 1, 1947

By A. D. Yell

"Recovery of water is always a major factor in the Beneficiation process. As Preparation Plants become larger the recovery of water for reuse, is a critical cost consideration. Tema Isenmann Inc in conjunction with our sister Company Multotec Manufacturing, has over the years, developed numerous different Screen Panels, Sieve Bends and Static Screens for dewatering. This paper will focus on a new innovation, the TeePee™ Panel which has double the open area of conventional Screen Panels. This results in efficient dewatering (reduced filter cake moistures) which allows for the use of smaller Vibrating Screens or increased capacity on existing Vibrating Screens. A major factor in the efficiency of any Screen Panel, including TeePee™ Panels, is the performance of the Vibrating Screen. If the Vibrating Screen does not have the required gravitational force or screen area to drain it will not dewater efficiently. Therefore a holistic approach has to be taken where the Vibrating Screen needs to operate at an optimal level, in conjunction with the correct Screen Panels, to achieve efficient dewatering. Key performance areas for Vibrating Screens are therefore detailed in this paper with an emphasis on important dewatering criteria. Case studies of different dewatering applications are included, where the use of TeePee™ Panels, has shown a marked improvement over conventional flat Screen Panels in reduction of filter cake moisture content.INTRODUCTION Dewatering can be done in a number of different ways and is largely dependent on the ore type, the particle size distribution and to what extent one needs to dewater will determine the method used. There are a number of different dewatering methods that can be used for particles above 200 micron, including Screen Bowl Centrifuges, Filter Presses, Static Screens, Static Sieve Bends and Vibrating Screens. This paper will focus primarily on Vibrating Dewatering Screens showing improved drainage and a reduction in the filter cake moisture content. KEY PERFORMANCE CRITERIAL FOR VIBRATING DEWATERING SCREENS For clarification the critical key performance criteria for Vibrating Dewatering Screens are set out in this paper. Dewatering Screens Vibrating Dewatering Screens are normally linear motion, either horizontal or inclined at 5 to 7° upwards with a vertical or back sloped plate at 45° to the rest of the screen deck. The back plate will often have screen panels in them to increase the dewatering capability, as shown in Figure 2 below."

Jan 1, 2017

By C. S. Griffith

Lithium Australia NL (ASX:LIT) and ANSTO Minerals have been working together since 2015 on the development of halide accelerated leaching for the extraction of lithium from lithium-bearing micas, spodumene and clays. This technology has been termed SiLeach® process. The driving force behind development of the SiLeach® process, initially, was to develop a hydrometallurgical process to extract lithium from micas and spodumene without the need for the energy intensive, high temperature processing conventionally applied to lithium extraction. This driving force remains today and continues to hold promise in realising the value of previously under-utilised lithium resources. A comprehensive understanding of the technology and its applicability to the processing of micas and spodumene currently exists, and the flowsheet has been rigorously piloted. Production of battery grade lithium carbonate has been demonstrate

By Y. Serres

In the past, conventional reflection seismic techniques were not very successful when applied to typical mining exploration: they lacked resolution in the shallow range or were not cost effective. By combining a light earth tamper source, special geophones and field procedures, a stacking process of the returning seismic events using a microprocessor system, and a sophisticated sequence of adapted digital data processing, Mini-Sosie achieves high resolution in the 100-ft to 4000-ft range. Additional advantages result from the very quiet nature of the source and flexibility of the system. Although Mini-Sosie might be used in the refraction mode, or for well velocity logging, it has found its main applications with the reflection technique.

Jan 1, 1978

By Will H. Coghill, I. L. Feld, G. D. Coe

"INTRODUCTION During the course of research on the beneficiation of the Big Seam iron ores of Birmingham, Ala., an urgent need was felt for quick iron assays of grab samples for mill control. Since the gangue minerals in these ores - quartz, limestone, and clay - all have about the same specific gravity, the use of a specific-gravity method was anticipated as a means of measuring the iron content. The idea of estimating the composition of a mineral mixture by measuring its specific gravity is by no means new. However, the usual method of carry in out this idea proved unreliable when applied to the Big Seam ores. The usual rapid method of determining specific gravity consists of measuring the volume of a known weight of sample that has been dried at high temperature. The inadequacy of this method led to the development of the rapid, modified, specific-gravity determination described in this paper.This work- was an incidental development resulting from research on beneficiation of iron ores by the Bureau of Mines, United States Department of the Interior, in cooperation with the University of Alabama and ore producing companies of the Birmingham district."

Jan 1, 1946

By Jorge Ganoza

Algunos concentrados de plomo contienen contaminantes que afectan la comercialización del concentrado de cobre debido a aspectos ambientales, así como la calidad del producto final. En ese sentido, el presente texto busca la forma de minimizar la presencia del plomo y de bismuto en el concentrado de cobre, a través de la flotaciónpor chalcopirita. De otro lado, dado que el plomo y bismuto son elementos que tienen similar comportamiento durante la flotación, es factible aislar los minerales de plomo y bismuto.

Nov 1, 2012

By S. Shankar

The phenomenon of re-entrainment is seen in many environments, such as sand dune formation, soil erosion, fugitive dust emission, spread of radio-nuclides from accidents involving nuclear weapons, etc. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of on-going research in the Respirable Dust Center on the prediction of ambient dust concentrations in mine atmospheres (Ramani, 1983) to identify the contribution of dust re-entrainment to the spatial and temporal concentration in mine airways and included wind tunnel and in-mine studies. A set of seven experiments was performed in the Lake Lynn Laboratory Mine of the U.S. Bureau of Mines under controlled conditions. Two types of source coal dust, anthracite and bituminous, were subjected to airflow with a range of air velocities and walking by two different walkers. Six sets of instruments were used along the test section for sampling the airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/s. Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg/m3 (standard deviation = 0.03 mg/m3) from an initial value of 0.02 mg/m3. The concentration of all (i.e., total) airborne dust increased to 0.17 mg/m' (standard deviation = 0.10 mg/m') from an initial value of 0.02 mg/m'. The action of personnel walking, however, caused higher amounts of re-entrainment. Average concentration of respirable and total dust at the center of the mine airway increased to values of 0.28 mg/m' (standard deviation = 0.12 mg/m3) and 1.53 mg/m3 (standard deviation = 1.0 mg/m3), from initial values of 0.03 mg/m3 and 0.05 mg/m3, respectively. It was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal dust bed. Depending on the level of activity and the amount of dust deposited in mine airways, re-entrainment may become an important source of airborne dust away from the point of actual mining.

Jan 1, 1994