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By Alain Duchesne, Dominique Fonfrede, Alan Broca

The technique involves the removal, in one piece, of an unwanted concrete pile section, exploiting the principle of crack propagation induced using gas pressure. The device, or pod, is made of a container in which an over-pressure is generated. After a predetermined time delay of 72 hours, gas and pressure are produced by the reaction between a calcium base chemical and water.

Jan 1, 2012

By W. P. Diamond

The explosion hazard of methane-air mixtures has become an increasingly serious mine planning problem, and an advance assessment of methane gas potential can therefore be essential for a safe and economic mine development program. As part of its coal mine health and safety program, the Bureau of Mines has developed a simple, inexpensive test to measure the methane content of coal samples obtained from exploration cores. The gas content of coal per unit weight as determined by the direct method test can be used as a basis for a preliminary estimate of mine ventilation requirements, and to determine if degasification of the coalbed in advance of mining should be considered. Since the Bureau began measuring the gas content of coal samples in 1972, experience has led to equipment and procedural changes, the most significant of which has been the development of a ball mill for crushing the coal sample to release the residual gas at the end of the desorption test period. This revised procedure replaces the crushing box and graphical methods described in earlier Bureau publications. The results of 583 direct method tests are summarized in tabular form. These results include data on the gas content of 125 coalbeds in 15 States.

Jan 1, 1980

By David W. Tongue

This report describes the engineering work leading to the design of an underground coal mine piping system to transport approximately 2,000,000 cubic feet per day of methane gas to the surface from degasification holes drilled horizontally into the coalbed in existing coal mines. Safety instrumentation for detection of gas leaks and provisions for automatic emergency shutdown are included in the design. It also includes specifications for a safe system of handling gas, water, and drill cuttings during drilling of the horizontal holes and recommendations for compressor and metering facilities at the surface. The main pipeline is recommended to be constructed of polyethylene plastic pipe joined by a butt fusion method while lateral lines and separator and meter piping at the horizontal holes are recommended to be screwed steel piping. The materials used are to be resistant to the forces of impact exerted by falling rock. The pipelines are to be suspended from the ceiling with pipe hangers. All steel components are protected from chemical corrosion by applying protective coatings and the vertical casing to the surface is protected from electrolytic corrosion by a rectifier station. Methane gas detectors monitor the mine atmosphere to detect the presence of gas leaks and a pneumatic plastic tubing line provides for control of the safety shutdown system. Both the recommended design and the required construction procedures are in compliance with the applicable Federal codes for coal mine safety.

Jan 1, 2012

By John A. Breslin

This report summarizes the principal activities and significant results of the Bureau of Mines respirable dust research program since passage of the Federal Coal Mine Health and Safety Act of 1969 and the Federal Mine Safety and Health Amendments Act of 1977. This program has investigated new and improved techniques and equipment to reduce or prevent the formation of dust during the cutting cycle; to dilute, suppress, or collect airborne dust generated during mining, handling, and processing; and to improve the measurement of dust levels for evaluation of engineering controls and for enforcement of Federal dust standards. The report is intended for mining industry dust control specialists and other interested parties. It includes a brief summary of the program to date, a section on future research plans and goals, and a list of publications resulting from the Bureau's respirable dust program.

Jan 1, 1982

By L. Roux

The initial evaluation of a coal deposit often raises uncertainty with regard to the accuracy of the reported Resources and Reserves. Reconciliation of results from mining and beneficiation with the original raw field data highlights deficiencies in original estimations. Credible Resource and Reserve estimation forms the basis on which an entire mining enterprise is motivated, initiated, funded, and established as a commercially viable proposition. This is required for sustainable extraction purposes and to support vital downstream industries such as power generation. Accurate determination of the density of the matrix of the material being evaluated is the key to credible values being obtained for Resources and Reserves. Losses between 15% and 20% of the Resource/Reserve can be realized if incorrect densities are applied to the tonnage derivation. Coal plies and particles have different relative densities, determined by the maceral composition, rank, and mineral and moisture content. These factors in turn contribute to the moisture, volatile matter, ash and carbon contents of a coal, which affect the overall density of the raw coal. More specifically, the relationship of ash to density and the effective matrix porosity were found to be critical in solving the greater majority of the problems in predictive calculations. A major deficiency identified is the inability to determine effective porosity, allowing absorption of adventitious moisture and altering the mass of the core sample. Although the volume of the raw material is altered through crushing, the change in mass after controlled air-drying, used with the original geometrical volume of the raw material, provides a credible air-dry density and allows the determination of the volumetric change related to effective porosity. This parameter can be validated through the evaluation of proximate ash using the ash-adjusted algorithm and a correction for the inherent moisture applied to also give a credible relative density value for an air-dried sample. A combination of theoretical, empirical, and reconciliatory evaluations of the available data, taken from the exploration phase through the mining process to final production, has shown that an integrated approach using the ash-adjusted density (AAD) methodology, in conjunction with other evaluative techniques, provides credible results with a considerably higher degree of accuracy than is currently possible.

May 1, 2021

By R. A. Cattell

Progress of Bureau of Mines research related to oil and gas during the past fiscal year has been marked by the publication of more than 40 reports on the various phases of the work . These include papers dealing with the production of oil and gas , transportation of gas , chemistry and refining of petroleum , thermodynamic properties of hydrocarbons , and the processing and utiliza- tion of helium . As an additional service to Pennsylvania oil operators , a new suboffice was opened in Bradford , Pa . , during the year . With this addition , the work of the Petroleum and Natural Gas Branch of the Bureau of Mines is now conducted in two large stations , the Petroleum Experiment Station , Bartlesville , Okla . , and the Petroleum and Oil Shale Experiment Station , Laramie , Wyo . , and three field offices and laboratories at San Francisco , Calif . , Dallas , Tex . , and Franklin, Pa., and two suboffices, Wichita Falls, Tex., and the newly opened suboffice at Bradford, Pa. In addition, this Branch operates large-scale helium-production plants in Texas, Kansas, and New Mexico, and maintains ex- tensive helium-bearing gas reserves in Texas and New Mexico. All helium opera- tions are supervised from headquarters at Amarillo, Tex. A small headquarters staff is in Washington, D. C. A backward glance at the road traveled during the past several years by the Petroleum and Natural Gas Eranch of the Bureau of Mines brings out a general background for the events of the fiscal year 1949. Throughout the fiscal year 1945, the activities of the Branch were still mainly concerned with such war activities as making special field studies for the Petroleum Adminis- tration for War, finding ways of increasing rates of production, and supplying data pertaining to the manufacture of aviation and jet-propulsion fuels. A period of adjustment came in 1946, characterized by a turning from war to peace procedures and efforts to give wide distribution to technical facts ob tained in wartime research; also, there came a realization that the demands of war had broadened the horizons of research. This was emphasized in 1947, when a peacetime program was restored, based upon the long view of the Bureau's place as a research agency in oil and gas. Close attention was given to tech- nical detail in 1948, and emphasis was placed on maintaining a balance between the industrial need for technical knowledge and Governmental-research possi- bilities in the fields of (1) withdrawal of petroleum from natural deposits, (2) utilization of petroleum and its products, and (3) commercial utilization of helium. Studies of petroleum production and utilization and helium production and utilization are the normal functions of the Branch. These functions (sometimes expressed in different words) have been the mainstay of this organization since initiation of the work. The details of approach vary with changing conditions, but, fundamentally, the functions have been the same in both peace and war. The work of the past fiscal year has emphasized the advantages that accrue when Government and industry join in a wise use of technical and scientific knowledge gained through research. Outstanding evidence of the beneficial results of cooperative effort by the Bureau of Mines and various organizations is found in the following typical examples, the details of which are discussed in the body of this report. Working in close cooperation with operators along the Gulf Coast, the Natural Gasoline Association of America, and the National Association of Cor- rosion Engineers, the Bureau found, through field testing, that corrosion protection by means of chromates in high-pressure gas-condensate wells costs less than $1 per million cubic feet of gas produced. Laboratory experiments to measure the corrosion effects of carbonic and propionic acids on various steels and alloy steels gave data that will serve as guides in the selection of new. materials for the construction of well equipment to be tested by industry under actual service conditions.

Feb 1, 1950

By G. Diáz

A basic technology coping with a wide range of secondary zinc sources has been developed. The process combines an electrowinning stage, a solvent-extraction unit and a leaching procedure. The acidity generated in zinc electrowinning, transferred by the organic solvent to the aqueous raffinate, is reused to leach the zinc secondary materials. The basic process recovering zinc is described in detail. The route recovering other valuable metals such as copper, cadmium and lead associated with zinc is also described. This non-ferrous metals recovery route is advisable for either ecological and/or economical reasons. Main results of an experimental program aiming at the demonstration of the suitability of the process for several feed materials are summarized. Waelz oxides, galvanizing ashes and EAFD coming from different sources were tested in laboratory and continuous pilot plant campaigns. High zinc recovery, low reagents and utilities consumption, and effluents meeting environmental regulation were confirmed. The paper also includes the main results of a feasibility study of an industrial "base case". A mixed raw material and Spanish EAFD and 20,000 ta of zinc ingots production were chosen. The SGH zinc recovery from secondary raw material by means of the clean, safe and profitable Modified Zincex Process has been demonstrated. This reliable technology is ready for industrial application.

Jan 1, 1995

By B. J. Moore

This publication contains analyses and related source data for 352 natural gas samples from wells and pipelines in 18 States and 5 foreign countries. All of the samples were obtained and analyzed during calendar year 1974 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economics. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Sixteen previous publications have presented the results of 10,479 gas analyses prior to 1974. The first three, Bulletins 486,4 576,5 and 617,6 contain analyses and related source data on

Jan 1, 1975

Jan 1, 1997

Although not immune from the problems affecting the U.S. economy generally, the mineral industry in 1991 contributed nearly $300 billion in the value of processed materials of mineral origin. Supporting this contribution, the Bureau of Mines continued the research and analytical programs highlighted in this annual review. Featured in 1991 were such relatively new programs as minewide monitoring applications in ground control and advances in processing of ceramics and composites, along with more traditional research into health, safety, and mining technology, minerals and materials science, and environmental technology. Under Bureau sponsorship, a National Minerals Policy Forum brought together some 200 executives from industry and Government concerned with minerals policy to begin a dialogue on developipng a policy statement on current minerals issues. A major feature of the forum was the keynote address by Secretary of the Interior Manuel Lujan, Jr.

Jan 1, 1992

By Bern Klein, Givemore Sakuhuni, Libin Tong

The use of continuous discharge centrifugal concentrators introduced in the early 1990’s for recovery of gold associated with sulphides has introduced a novel application niche for gravity concentration which could not be realized with the low mass yield batch and semi-continuous concentrators. A typical application is scavenging gold associated with sulphides from flotation tails which has potential to increase productivity by reducing gold loss to tailings and lower grinding cost by using a coarser grind. However, the full potential of this technology has not been fully exploited partly due to the lack of reliable small sample procedures to demonstrate applicability. This paper introduces a bench-scale procedure developed to characterize the Knelson Continuous Variable Discharge concentrator (CVD) for scavenging gold from flotation tails. The procedure code named gravity release analysis was derived from standard flotation release analysis. It is a modification of the gravity recoverable gold and gravity amenability test in order to best simulate continuous centrifugal concentration. Based on this iterative procedure, a gravity release index similar to the flotation rate constant, for measuring individual mineral gravity susceptibility for an ore is introduced which can be a useful quantitative measure to both predict application of centrifugal concentration and for plant design. The gravity release analysis procedure was tested on a polymetallic flotation plant tailing at Myra Falls, BC, Canada and results show that it can predict CVD performance. The gravity release index for gold was observed to decrease with each successive cleaner stage showing that the initial stages recover liberated gold whilst successive runs recover gold associated with sulphides and or gangue. The difference in magnitude of the gravity release index for different mineral species shows the species separable by centrifugal concentration.

Jan 1, 2014

By C. Sunderman, R. Jacksha

"Mine monitoring through various sensors is a vital component of successful miner safety and health programs. Data from environmental, geotechnical, infrastructure and other types of sensors are increasingly used to discover and mitigate health and safety concerns in underground mines. In many smaller underground mines, as well as in the new development headings of larger underground mines, leaky feeder communication systems may be the only available means to transport crucial monitoring data. In addition, data transport is increasingly being delivered using Internet Protocol (IP), while older forms of serial communication are being retired. This paper presents the selection, configuration and testing methodologies employed by researchers from the U.S. National Institute for Occupational Safety and Health (NIOSH) to integrate commercially available land mobile data radios into an existing leaky feeder communication system to provide IP data transport.IntroductionTo enhance the health and safety of their mining workforce, mine owners and operators are increasingly installing environmental monitoring and control systems in underground mines. Real-time, mine-wide monitoring is becoming a reality with the implementation of the Industrial Internet of Things (IIoT) into the underground mining industry (Zhou et al., 2017). However, not all underground mines, especially smaller mines and new development headings in larger mines, have the information technology infrastructure in place to handle the data transport requirements for the newer Internet Protocol (IP)-based technologies that are part of IIoT.This was the case with a mine in the Western United States. It lacked the infrastructure to perform critical monitoring in remote headings. Therefore, the mine partnered with the U.S. National Institute for Occupational Safety and Health’s (NIOSH) Spokane Mining Research Division (SMRD) to develop and evaluate a cost-effective solution for the real-time monitoring of geotechnical conditions in relatively remote sections of the mine. This paper describes SMRD’s solution to leverage the mine’s existing leaky feeder communications system to achieve IP data transport using commercially available land mobile data radios (NIOSH, 2013; Forooshani et al., 2013; Novak, Snyder and Kohler, 2010; Yarkan et al., 2009). The solution, fully evaluated in laboratory and mine environments, requires no modifications to the existing system, is economical, simple to implement, and reliable. It also allows for transition to higher-bandwidth IT networks, such as fiber optic or WiFi, should they become available."

Dec 1, 2018

By F. Concha

A robust theory of sedimentation-consolidation evolved and was accepted by researchers world-wide in the last two decades of the 20th century. This theory provides a reliable method of thickener design and simulation. However, a process model, simple or sophisticated, empirical or phenomenological, is useful only if it is possible to determine, in an objective way, its experimental parameters. Research workers at the University of Concepción, together with Cettem Mineral Technology Center, created an integrated system of thickener design, simulation and control, including instrumentation, algorithm and software, which can be used by personnel in industry without specialized knowledge of thickening theory. In the paper, the development of three instruments for the measurement of pulp concentration, solid flux density and sediment compressibility is described. Each instrument uses software for data input, parameter calculation and results display. The paper also describes software for the optimization of the experimental parameter and for the design and simulation of industrial thickeners. Finally, mathematical algorithm and control strategies based on the phenomenological model are presented and compared with classical feedback control.

Jan 1, 2014

By D. D. Eyer

New or improved technology will continue to drive productivity improvements through the next decade. In January 1988, I presented a paper titled, "Large Underground Mines of the 1990s? before the SME. I will follow some of the themes developed in that paper as modified by our experience in the past two years. In order for a coal company to be profitable today, it has had to reduce unit costs experienced in the past. This is because the current average realization, even accounting for a recent strengthening, remains below that of a few years ago. Doing business as was done in the past is not good enough. The coal industry needs to increase productivity in the range of 5-10% annually merely to stay even with rising costs. Underground productivity has been increasing more rapidly than that for surface mining. With the exception of the Powder River basin of Montana and Wyoming, underground productivity has caught up with that for surface mining in many regions of America. There are a number of technological factors which have attributed to increases in underground productivity and which should be factors in the future.

Jan 1, 1990

By G K. Robinson

Variations in many aspects of physical and chemical grade are often of concern to mining operations and mineral processing plants. In most circumstances these amounts of variation are predictable. At the time of planning new operations, we should be able to predict the amount of sampling and testing variation which our sampling devices, laboratory procedures and on-stream analysis devices will achieve. We should know how well our stockpiles, reclaimers and bins will homogenise material (or whether segregation will actually increase the amount of variation). We should be able to predict the amounts of variation that will occur on the important time or tonnage scales at the crucial p oints in our proposed operation. And once these amounts of variation are reliably known, mine planning will seem a little bit more like dealing with known knowns rather than like dealing with unknown unknowns.The first step towards quantifying amounts of variation for planned operations is to assess amounts of variation for existing operations. How many operations have estimates of amounts of variation in their databases? How often are people able to partition amounts of variation into amounts due to sampling error, amounts due to sample preparation, amounts due to assaying, and the amount of real variation in the stream of material?CITATION:Robinson, G K, 2012. Making sure that the amount of grade variation is a known known, in Proceedings Project Evaluation 2012 , pp 159-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Meng Xiao, Peng Huang, Lizin Lan, Feng Ju, Shuai Guo

"Through changing the axial load on backfilling material compaction test to reflect different overlying strata pressure on backfilling material, the stress-strain relations in the compaction process of backfilling material under the geological condition can be obtained. Based on the characteristic of overlying strata movement in backfill mining, a model of roof thin plate is established. By introducing the stress-strain relation in compaction process into the model and using RIZT method to analyze the bending deformation of roof, the bending deflection and stress distribution can be obtained. The results show that the maximum roof subsidence and maximum tensile stress occurring at the center are 255mm and 5 MPa, respectively. Tensile fracture of roof under the geological condition of Dongping mine did not occur. The dynamic measurement results of roof in Dongping mine verify the theoretical result from the aforementioned model, thereby suggesting the roof mechanical model is reliable. The roof thin plate model based on the compaction characteristic of backfilling material in this study is of importance to research on backfill mining theories and application of backfilling material characteristics.INTRODUCTIONSolid backfilling mining (SBM) is a green mining technology in which the solid waste materials is placed into the gob to support the overlying strata and to control roof's subsidence and movement (Miao, 2012; Miao et al., 2010, 2015). SBM has been successfully used in several mines to solve many problems, including coal extraction under buildings, water bodies and railways, surface subsidence, and environmental problems. Good results have been obtained in many mines (Zhang et al., 2009). The key in the application of SBM technology is controlling strata movement. However, the critical factor influencing the controlling effect of strata movement is compaction characteristics of backfilling materials. Thus, a roof model of SBM is built based on the filling materials' compaction characteristics. A subsidence equation and the critical failure condition of roof was given and field verification was performed at Panel 15061 of Donping Mine."

Jan 1, 2016

By V. A. Kharchenko, V. M. Yeremeev

INITIAL PRECONDITIONS To solve tile problem of using the potential reserves of the different coal ranks efficiently (the coal reserves being many times superior in quantity to those of natural gas and oil) one must realise an integrated estimation of the coalfields' and coal deposits' reserves. The actuality of this problem increased especially in the recent years, when the Russian coal industry is being restructured. A structural reorgaisation of this industry, in order to in- crease its efficiency, covers a large spectrum of social and economic problems, comprising a withdrawal from mining the coal reserves that are unsafe from the standpoint of economy and labour protection. According to the information supplied by the 'Rossoogol' company, the Russian coal industry, accounting for abut a fifth of the world coal reserves, has a rather unsafe resource base, for about 5% of the reserves involved in mining do not correspond to the world practice conditions, regarding the coal grade, thickness, geological conditions, proneness to coal and gas outburst hazards. These concern first of all the Moscow, Kizelovsk and Donetsk coal basins, the Prokopievsk-Kiselevsk district of the Kuzbas basin and several other coalfields. Thus, the problem of efficient potential coal reserves' utilization calls for a paramount solution of two basic problems, namely: a) a comparative coalfields' and sections evaluation, and their ranging, in accordance with their industrial importance; b) choosing the 'active' reserves good to be efficiently mined under the present-day conditions. PRINCIPLES OF EVALUATION The investigations that had been carried out make it possible to formulate the following basic principles of the coalfields' reserves' estimation (or assessment). 1. The necessity, possibility and expediency of coal reserves' industrial exploitation are determined by a set of natural, technical, technological, practical, economic, environmental and social factors, thus calling for an integrated and gradual approach to problem solving. 2. One cannot consider the results of same reserves' estimation as being invariable because the former depend both upon constant (mainly natural) and market demands for different grades of coal (those of different power engineering and technological situations), capital investments, material and labour resources, economic (price-forming), technical, technological, environmental and other factors. 3. The rational size and sequence of the operating mines' and reserve sections' resources' involvement into mining depend upon the final aim of posing the problem, whose variants may be (the corresponding limitations being considered) providing for a maximum run-of-mine output (these essentially featuring the past stages of the industry's evolution); providing for a maximum efficiency, measured possibly by the specific or absolute indices of profits an expenses, labour productivity e. al. ; providing for a maximum extraction (maximum integrate utilization) of the known reserves. In this case an important park goes to the economic evaluation (or assessment) of useful application of the by-products being extracted (methane, mine water, rack) compared to the expenses necessary for their utilization. Regarding the steam coal (posing the problem any way it be possible), and extreme limit to the absolute non-efficiency of the coal reserves' exploitation may be posed, using the proportion of energy obtained from the possible amount of the coal to be extracted to the energy consumption necessary to extract, prepare, haul and consume this amount of coal. 4. The most reliable and efficient solutions providing for opening the reserves can be obtained for group of mines, rather than at the level of an individual mine section or an individual mine because it is only in the former case that the possibilities to re- distribute the expenses necessary to develop the good for mining and worse sections and seams can be realized to the greatest extent. Therefore the prospective approach to be considered is the one providing for an integrated organization and choice of the optimum combination of the variants of the ways to use the mines in operation and the free sections of the region in order to satisfy the growing up requirements for coal rather than the one providing for individual mine sections' resources' evaluation. 5. The future possibility and expediency of coal reserves' industrial exploitation will depend upon the prospects to implant at the mines in operation and reserve sections new engineering and technological elements and coal extraction technologies which may essentially change the actual idea concerning the coal reserves worth of being developed in an efficient way. For example, reserves not available to be exploited using conventional coal extraction technology may be regarded as potential resources for in situ gasification, e. g. the operating mines' reserves (non-commercial and non-mined commercial ones), balance and outside balance reserves of the free sections having proved not available to be mined using conventional coal-extraction technologies, as well as the non-extracted reserves of the abandoned and closed mines.

Jan 1, 1996

By D. G. Mason

During the design of copper refinery tankhouses, there is a need to develop mass balance calculations for many process components, so that optimum physical plant configuration is achieved. Each mass balance is complex, possibly with over 120 interactive variables as basic input data. Recent developments in tankhouse design (e.g. permanent cathodes) have greatly increased the design options available for any project, multiplying even further the requirement for calculations. In the past these calculations were tedious and susceptible to human error. A comprehensive computer program can now simplify the task of the process metallurgist, enabling more sophisticated and sensitive plant designs to be produced. The paper describes the successful development of a flexible mass balance program that originallly was used in a feasibility study which had to be completed within a short time schedule. The program has been further developed and used for design and energy calculations; it can be usefully applied to existing plants to assess the impact of variations in operating parameters. The software takes account of staged liberation, electrolyte purification bleed and generates a reliable process inventory listing: it can also cope with stripper starting sheet options and disparate commercial circuits.

Jan 1, 1987

By Charles D. Litton

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due to both nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustions. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines.

Jan 1, 2008

By S. Zhang, Z. Hua, D. Feng, X. Tong, X. Xie

The separation and beneficiation of low grade collophanite has long been a technical challenge in phosphorous production. It requires the joint efforts of process design, reagents optimisation and operational control. In this study, the statistical response surface method was applied for determining the optimum reagent dosing in the flocculate flotation of a low grade (18.59%) collophanite ore. The dosage of three reagents, including a pH regulator (Na2CO3), depressant (Na2SiO3) and flocculant (modified starch), were input parameters of the modelling design. Two quadratic mathematical models were derived for prediction of grade and recovery based on the statistical design. Statistical analysis of the experimental results validates the reliability of the models. Through further calculation, the optimum dosage of the three reagents were found to be 3,020g/t Na2CO3, 1,990g/t Na2SiO3 and 880g/t modified starch, with which a maximum recovery of 75.81% and P2O5 grade of 30.08% was obtained from flocculate flotation test. Keywords: Process optimisation, modelling, froth flotation, collophanite ore, response surface methodology

Jan 1, 2020