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By Aubrey Mainza, Malcolm S. Powell

"A hydrocyclone with two vortex finders, named the three-product cyclone, has been successfully tested in the Platinum industry for dealing with the dense chromite found in UG2 ores. This dense component preferentially reports to the cyclone underflow, resulting in an over-ground fine chromite component in the final product. The dense media effect caused by a high chromite concentration in the cyclone feed produces a coarsening of the cyclone overflow, which results in loss of recovery through over-size material in the float feed. The fine barren particles of chromite that report to the overflow are recovered through entrainment in the flotation process, resulting in detrimental contamination of the slag produced from the concentrate.With the three-product cyclone a middlings product has been extracted that has a higher concentration of fine chromite. This volumetric stream flow represents a small percentage of the total cyclone feed and it is thus possible to treat it separately via fine screening to remove the fine chromite from the system and recover coarse silica."

Jan 1, 2003

By Glenn C. Reed

This report is one of a series describing mineral investigations within the Missouri River Basin in Montana. The primary purposed of these investigations is to provide information to agencies of the Department of the Interior and others concerned with the planning of Federal power developments in the basin. This report is limited in score to consideration of mineral deposits of presumed inventory value within Gallatin County, Mont. The field investigations were made during the fall of 1948.

Jan 1, 1951

In this paper High Pressure Grinding Rolls(HPGR) was utilized to pretreat CVRD southern specular hematite for enhancing the pelletization of the refractory hematite. The process parameters of HPGR, balling and firing were optimized, and the mechanism of HPGR was demonstrated by determining the surface activity by means of Blaine specific surface area tester, laser size analysis, scanning electron microscopy (SEM),X-ray diffraction (XRD), micro calorimeter and pelletability index. It is shown that the pelletization of the refractory hematite was greatly improved. The drop strength of green balls increases from 3.4 times to 13.6 times from 0.5m height while the bentonite dosage decreases from 2.2% to 1.3%.The compressive strength of roasted pellets also reaches 2500N/pellet. The mechanism of the pretreatment of CVRD southern specular hematite concentrates by HPGR is revealed that the surface activity is improved by an increases in specific surface area and the amount of micron size fractions, and higher lattice deformation and defects due to the fractures occurring inside particles during static pressure comminution, resulting in more wetting enthalpy, higher pelletability index and good property of roasting.

Jan 1, 2014

By G. Binks

In 1997, the Zinifex Hobart Smelter ceased ocean disposal of jarosite and the flowsheet was converted to reject iron as paragoethite. This paper describes the evolution of the flowsheet since the changeover and considers future flowsheet developments. The major change to the flowsheet has been an increase in the silica content of the calcine resulting from treating increasing levels of Century concentrate. The high silica levels impacted on the paragoethite precipitation stage, causing a deterioration in the settling and filtration characteristics of the paragoethite and an increase in the contained zinc level. The implementation of a two stage neutral leach step has enabled the flowsheet to cope with the higher input silica levels. Future developments include an understanding of the form of the zinc in the paragoethite and options to lower the zinc level to improve the overall zinc recovery.

Jan 1, 2006

By John H. Soulé

"INTRODUCTION Spodumene and lepidolite were shipped from the Harding pegmatite deposit, Taos County, N. Mex., in the period from 1930 to 1930. Tantalum minerals were noted as early as 1924 and described in 1931 3/ but no tantalum ore was shipped until 1942. The deposit was mapped and studied by geologists of the Federal Geological Survey and engineers of the Bureau of Mines late in 1942 and early in 1943, and a Bureau of Minus exploratory project was carried out in 1943. 4/ Thu following report presents the results of that project.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Minos has as its primary objective the more effective utilization of our mineral resources to the end that they make the greates possible contribution to national security and economy. It i the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lovell B. Moor, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallugiical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, Assistant Director."

Dec 1, 1946

By Sandra K. Zacharias

Brass, a deliberate alloy of copper and zinc, has been known since before Roman times. There are two main methods of making brass: (1) Cementation or calamine process - crushed zinc ore (calamine, ZnC03 , or calcined calamine, ZnO), is mixed with charcoal and small pieces of metallic copper and heated to about 900°C in a closed crucible, (2) Alloying - metallic copper and zinc are melted together in a reverberatory furnace. According to most modern authorities (e.g. Smith and Forbes 1955), the calamine process was the only one used in western Europe prior to the 18th century. At that time, the alloying technique began to take over, because metallic zinc was successfully produced on a large scale for the first time. Previously, this had been a problem because zinc vapourizes at 906°C or about the same temperature at which it can be reduced from its ore. Thus, some means had to be devised to collect and condense the zinc vapour (Tylecote 1976). Metallic zinc was known, however, earlier than the 18th century A.O. Several early finds have been made, including a rolled sheet of metallic zinc found in excavations at the Athens Agora dating to the 3rd to 2nd century B. C. (Farnsworth et al. 1949). The Chinese were producing zinc by at least the 10th century A. D. and, by the 17th century, Chinese zinc ingots were being imported into Europe by the Dutch East India Company (Needham 1974). Metallic zinc is also mentioned in several European documentary sources from the 16th century (e.g. Paracelsus, Agricola). This study traces the changes in Western brass making methods from Classical to Renaissance times by examining documentary and archaeological evidence.

Jan 1, 1999

By Raymond G. Travis

This paper, which describes mining methods and practices at the Hurricane Creek bauxite mine of Reynolds Mining Corp. in central Arkansas, is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Hurricane Creek mine is in sec. 12, T. 2 S., R. 14 W., and sees. 7 and 18, T. 2 S., R. 13 W., Saline County, Ark., about 4 miles east of Bauxite. (See fig. 1.) Bauxite has been mined underground at the Hurricane Creek property since 1942. The operation is notable for relatively high recovery of bauxite under the adverse conditions of unconsolidated water-bearing overburden and unstable clay floor. Controlled caving, timbered stope walls, and efficient drainage systems on the surface and underground have minimized the problems and raised ore recovery about 25 percent above that formerly obtained.

Jan 1, 1961

By M D. Urbani

HiTec Energy Ltd has been conducting research since 1996 into novel process routes for the treatment of low-grade and waste manganese sources for the production of high value and high quality electrolytic manganese dioxide (EMD) for the alkaline battery market. HiTecÆs approach is to treat previously unsaleable manganese deposits and mine site tailings using a novel sulfur dioxide leach route, followed by purification and electrowinning to generate the sought-after EMD product by an environmentally superior processing route to those presently practiced throughout the world today.HiTec Energy Ltd expects to be in commercial production with its Stage 1 facility in Kalgoorlie in the last quarter of 2004 for the production of 12 500 tpa EMD. With this production facility being adjacent to a laterite nickel producer with available waste manganese units, the opportunity arose for HiTec to combine its existing technologies with processes (that will be discussed in this paper) to turn two waste by-products into products that are used for high-tech purposes.HiTec Energy Ltd and the Parker Centre have had a collaborative research relationship for a number of years in areas involving EMD and battery related technologies. Meanwhile the solvent extraction (SX) group of the Parker Centre (CSIRO Minerals) has developed SX processes to separate manganese from nickel and cobalt. A project was initiated by HiTec Energy to recover manganese from waste laterite leach solutions using SX technology. Batch tests were conducted to select a suitable organic system for the extraction of manganese in terms of selectivity and extraction and stripping kinetics.A total of eight organic systems were tested by determining pH isotherms of metals using a laterite nickel process waste stream. Two organic systems, the Versatic 10 and Versatic 10/synergist systems, were chosen for further test work with Shellsol D70 chosen as the diluent for both systems.The Versatic 10/synergist system would be advantageous over the pure Versatic 10 system because fewer SX stages are required, resulting in a smaller organic inventory and lower capital costs. The risk of gypsum formation is also significantly lower with the synergistic system.

Jan 1, 2004

By Carlton H. Baab

In June, 1981 the Electric Power Research Institute (EPRI) issued a report titled "Control Systems in Coal Preparation Plants" to determine the status of instrumentation and automation systems in the coal preparation industry. EPRI concluded that the control systems presently being employed in the U.S. coal preparation plants "are relatively primitive compared with those in other mineral processing industries; and analytical instrumentation is virtually non-existent". Until recently, clean coal has had a low selling price and satisfying the purchasers' specifications required only minimum cleaning. However, it is becoming more apparent that the increases in coalfired utility power plants forced outage rates are relative to the deterioration in the quality of fired coal. Utility companies are becoming aware of the economic value of reducing the variability of ash, moisture and sulfur in steam coal purchase orders. New contracts are currently being negotiated between electric utilities and coal producers that include provisions for increased penalties if the product does not meet specifications. With tighter specifications on the quality of steam coal, interest is increasing in more sophisticated control systems. One type of device that is currently assisting the preparation plant operator optimize and control the coal cleaning process is nuclear based instrumentation. Nuclear instrumentation includes methods for measuring weight, level, and density as well as for performing elemental analysis on coal. This paper discusses the various types and applications of nuclear instrumentation currently in use in the coal preparation industry.

Jan 1, 1983

By F. P. Hassani, Jacque Ouellet, M. Hossein

A laboratory investigation was undertaken to evaluate the effectiveness of different binding agents in a paste backfilling operation suitable to be used in a sulphide-rich environment. Different combinations of Portland cement and fly ash type C as well as ferrous slag were used as the binding agents. The unconfined compressive strength of the samples was measured for extended curing periods. The results indicate that the addition of 3% slag in the binding agent mix could produce strengths up to 0.5 MPa in the samples under investigation. For higher binding contents, the addition of Portland cement will lead to higher availability of calcium hydroxide and calcium aluminate, which are susceptible to deterioration from the phenomenon known as sulphate attack. Using slag, on the other hand, will reduce the permeability, availability of calcium hydroxide, and dilute the calcium aluminate ions reducing the susceptibility of the samples to sulphate attack. However, gypsum will form which could have the same detrimental effect on the strength of the treated matrix. Therefore, special attention must be given to the content and properties of agents used to activate the pozzolanic properties of the slag.

Jan 1, 2001

By Brian Lewis, Reinhold Daykin Schnell

Blasting is the primary and most effective method for breaking and moving material at most mine sites. The blast design is often adjusted in efforts to optimize the effectiveness of the blasts’ explosive energy while minimizing costs. When adjusting blast design parameters, it is important to adjust one parameter at a time, observing and analyzing the potential effects of the change on the overall blast performance.

Feb 6, 2023

By Q Qu

Reliable prediction of longwall gas emission sources and rate plays a critical role in mine ventilation and methane drainage capacity planning. Over the years, Australian longwall mines have been using the historic Winter method and the Flugge method in modelling specific gas emissions (SGE). The predicted results often experience high discrepancies from the operational reality. To improve gas emission prediction, post-mining gas contents were measured in several mines in Qld and NSW by safely drilling core holes into the longwall goaf. The results revealed many new insights into gas emission characteristics from different coal seams and the drawbacks of the European methods in their use in high-production gassy Australian longwall mines. Based on measurement data, a new, time-dependent gas emission prediction model has been developed. Considering several factors such as caving, desorption and production rate, the new model can predict more accurate and meaningful gas emissions to meet today’s needs in mine gas emission management. A case study is provided to demonstrate the application of the new SGE model.

Oct 12, 2022

"Syncrude Canada Ltd. operates one of the largest surface mines in the world. The mining operation has two distinct phases: (1) the removal of the overburden, utilizing trucks and shovels; and (2) the mining of oilsand with drag lines and bucketwheels. Both phases combined move approximately 330 000 BCM per day.In support of current production demands and to provide a contingent oi/sand source, Syncrude has developed an Auxiliary Production System (APS) supported by the truck and shovel operation. This system utilizes oilsand sources within the existing mine area on an as-needed basis.The recent increased capabilities of the processing plant to handle a larger volume of oilsand has increased the reliance of the APS system. To facilitate the increased capacity, an auxiliary mine was developed external to the Base Mine operation with a production capacity of4.7 MBCM of oilsand per year.Development of the Northwest Auxiliary Pit began in January 1990, with the first cubic metre of oilsand taken to the plant in June, 1990. The Auxiliary Pit, as designed, has a total ore reserve of 68 MBCM of oi/sand."

Jan 1, 1993

By E. Rubenstein, V. Gangrade, K. V. Raj, M. L. Harris

Underground stone mine ventilation is characterized by large openings with low resistances. These mines primarily face three challenges: moving adequate volumes of air, controlling and directing the airflow, and planning ventilation systems that work well with production requirements. Given these challenges, this paper examines the data collected by the Mine Safety and Health Administration (MSHA) to determine the extent to which respirable crystalline silica (RCS) and diesel particulate matter (DPM) are an issue in underground stone mines. Out of 522 sampled mines, there were 108 personal samples exceeding the RCS Permissible Exposure Limit (PEL) during 2000–2020. DPM were more prevalent than RCS in these mines with 382 personal samples exceeding the DPM PEL out of the 929 mines sampled during 2002–2020. Dilution of DPM is usually the defining parameter for design of mine ventilation systems in largeopening underground stone mines. With this knowledge, focused attention can be directed to these mines so that appropriate prevention and mitigation techniques can be utilized to prevent stone miners’ exposure to RCS and DPM and subsequent respiratory diseases.

Mar 2, 2022

By Ismael Vemdrame Flores, Lindaura de Souza Cândido D’ Avila, Maurício Covcevich Bagatini, Arthur Felipe Lino Oliveira, Rafael Adriano Lopes Júnior

The use of pellet feed to adjust the chemical quality of the sinter is an alternative to the depletion of iron ore reserves. However, the addition of ultrafine in the sintering process can cause decrease of permeability and consequent drop in machine productivity. In this context, the present work investigated the addition of natural and ground pellet feed, evaluating its effects on cold agglomeration for sintering and quality of quasi-particles produced. Eight typical mixtures with industrial composition were produced in the laboratory, replacing Sinter Feed with different percentages of Natural Pellet Feed (NPF, 91% <150 μm) and Ground Pellet Feed (GPF, 83% <44 μm). The mixtures were subjected to cold agglomeration tests and the quasi-particles produced were evaluated by screening, shatter test, permeability test and disintegration into primary particles analysis. There was a decrease in the mean particle size of quasi-particles and reduce in permeability with addition of the ultrafines. The addition of NPF favored the layering mechanism in larger quasi-particles. The coalescence mechanism occurred for larger additions of NPF and GPF, being more expressive for GPF additions.

Oct 1, 2019

By Burt G. Look, David W. Lacey

"Certification of foundation capacity during the construction phase is often assessed by strength or weathering state descriptors based on visual observations. This case study used the Point Load Index (PLI) test as a quantitative tool in the construction certification of a pile’s design capacity. Construction phase tests were completed on irregular sized rock samples whilst comparable design phase testing was completed on intact rock core samples. Statistical comparisons were made to assess the repeatability between the PLI tests, with best-fit Probability Distribution Functions (PDFs) determined for both datasets. Pronounced differences were observed based on the PDF adopted to characterize the PLI dataset, the consequence of which would be a significant change to the pile’s design capacity. The adoption of the lower quartile value is shown to satisfy both design conservatism and construction simplicity requirements. The commonly held belief that rock samples produced during socket excavation may be biased towards the higher strength portion of the rock mass, is shown to be invalid for this site. As the central bridge piers were certified using Plate Load Tests (PLTs), the resultant load-settlement relationships were compared with the PLI strength assessments made for similar materials recovered from the adjacent abutment piles.INTRODUCTIONThe upgrade of the Foxwell Road Overpass across the Pacific Motorway in South East Queensland required the duplication of an existing four span bridge structure. The foundations of the new bridge included the installation of 1.2m diameter cast in place (bored) piles at the bridge abutments and 900mm diameter cast in place (bored) piles below a retaining wall to be constructed adjacent to the existing abutment.The site geology was dominated by the Palaeozoic Neranleigh–Fernvale Beds, predominantly comprised of argillite, sandstone and greywacke. Limited soil materials existed at the site, with Extremely Weathered (EW) rock typically encountered within metres of the existing ground surface. The exception to the existence of shallow rock were locations where existing filling of the site had occurred – i.e. approach embankments to existing bridge structure.Capacity of pile sockets is typically assessed onsite by descriptive rock strength or weathering assessment. Such descriptors encompass a wide range of values and lack precision. Due to the subjectivity of such assessment techniques – a factor of 3 is often observed in terms of strength assessment based on one’s interpretation of rock strength descriptors alone – uncertainty on site often occurs regardless of whether a lower bound, average or other characteristic design parameter applies."

Jan 1, 1900

By A. B. Hooker, L. C. IlsLey

The greatest hazard of early mining was from explosions of methane ignited by open lights . With the advent of safety lamps and forced ventilation this hazard was greatly reduced until the application of electricity to modern mining not only multiplied the sources of gas ignition but the accompanying , machines and haulage systems increased the amount of explosive dust , through which a methane explosion is more liable to become a major mine disaster , and thus greatly furthered the need of adequate ventilation to keep down the concentrations of methane . Adequate ventilation is still the best preventive of such explosions . However , even with a well laid out and controlled ventilating system the amount of air passing through entries and rooms is liable to vary within wide limits because of open doors , falls of rock , or other accidental causes . The percentages of methane under normal conditions should therefore be kept so small that they will not be increased to explosive proportions by short interruptions in ventilation . Mine ventilation and methane detection are inseparable safety precautions . The increasing importance of ventilation necessitates more accurato determinations of the methane concentrations throughout the mines . This paper discusses in detail some of the steps in the development of methane detection and specially notes the more accurate detectors now available . One of the earliest means of detecting methane was by a candle . About 1835 , John Buddle , Sr. , a noted mining man of his period , when questioned by a Parliamentary Committee as to the safety of using candles , replied :

Jun 1, 1933

By Thomas C. Denton

The Old Reliable copper mine was first examined by Harlow D. Phelps , an engineer of the Bureau of Mines , in October and November 1942 , in compliance with a request from the War Production Board , which furnished copies of assay maps of the 100- and 200-foot levels and requested that they be check-sampled . The author and R. li. Grantham and W. D. Hughes , engineers of the Bureau , made a second and more detailed examination later , after a number of manways had been opened that were inaccessible when the first examination was made .

Feb 1, 1947

By Thom Mambe, Angelo Fernando

The objective of this work was to identify key parameters related to the reduction of the sulphur content in ammonium diuranate (ADU), and the identification of solid products being formed under various operating conditions. A laboratory-scale, continuous ADU precipitation circuit was assembled using a glass reactor vessel immersed in a temperature-controlled water bath. A pre-prepared uranium feed solution was fed continuously using a peristaltic pump. Anhydrous ammonia mixed with compressed air was metered and pumped using a double-headed peristaltic pump. An over-head mixer was used to keep the solids in suspension. The precipitated ADU slurry was removed from the reactor at the same flow rate as the feed solution. The slurry was sampled to generate ADU solids for chemical and physical analysis after four hours of continuous operation to ensure steady-state conditions. The following variables were studied to determine their influence on the sulphur content in the resulting ADU. (a) sulphate:uranium molar ratio in the reactor (1:1, 1:5, 1:10 and 1:20) (b) precipitation pH ( pH 6, 6.5, 6.9, 7.5 and 9) and (c) precipitation temperature (40C and 60C) A total of 18 tests covering the above parameters were conducted, and the results indicated that the sulphur content in the resulting solids was highly dependent on the reaction pH. Out of the pH levels tested, tests completed at pH 6.9 and 7.5 generated solids containing the lowest sulphur contents, between 0.5 to 1.5% S uranium basis (UB). The sulphur content in solids was found to vary linearly with the sulphate:uranium ratio in the feed solution, showing a statistically valid correlation. The impact of temperature was minor between 40°C and 60°C, with a slight advantage at higher temperatures. Tests at a sulphate:uranium ratio of 1:1 produced solids with the lowest sulphur contents. The influence of pH or temperature on sulphur content in solids was almost non-existent at this sulphate:uranium ratio. Precipitation pH is the major factor influencing ADU sulphur content, followed by the uranium to sulphate ratio.

Jan 1, 2020

By P. O. Parfitt

The Critical Path Method has proved its usefulness at Mcintyre Porcupine Mines Ltd. This paper illustrates the techniques of network construction and analysis, and the application of the method at the Mcintyre copper mine to various projects in the gold mine. C.P.M.'s use in a mill maintenance project is also discussed.

Jan 1, 1966