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By Herry Poernomo, Agus Prasetya, Iga Trisnawati, Himawan Tri Bayu Murti Petrus, Gyan Prameswara, Panut Mulyono

We studied yttrium extraction from untreated zircon sand processing waste tailings. Xenotime mineral as the rare earth element source with an abundance of yttrium (REY) was detected in sufficient grade for extraction. As much as 9.03% yttrium exists in zircon tailings (analysed by X-ray fluorescence spectrometry). The presence of yttrium was confirmed by X-ray diffractometry in xenotime minerals, which are yttrium carriers (Y-PO4). The purpose of this research was to determine the effect of leaching conditions on yttrium recovery from zircon sand after alkaline fusion treatment. Alkaline fusion was chosen to decompose phosphate into hydroxide in the xenotimemineral,which will reduce further required hydrometallurgical processing.Alkaline fusionwas carried out for 3 h at 450 °C, with a ratio of sodium hydroxide to zircon tailings sand of ~ 1:1. The alkaline fusion product was leached with water, followed by hydrochloric acid treatment to leach the yttrium. Yttrium recovery reached 87% under optimum conditions (60 °C, 1MHCl, and solid-to-liquid ratio = 1/10 for 7.5 min). A suitable model for yttrium dissolution with hydrochloric acid was diffusion through a solid particle ash layer. The calculated activation energy (EA) for this model was 20.21 kJ/mol.

May 26, 2020

By George A. Savanick

Borehole (slurry) mining, in which a tool incorporating a water-jet cutter and a downhole slurry pump mines phosphate through a borehole, was field tested in northeastern Florida as part of a Bureau of Mines program to increase the domestic availability of critical minerals. Approximately 1700 tons (1.54x106 kg) of phosphate ore were mined at 40 tph (10.1 kg/s) from a depth of 250 ft (76 m). The borehole was filled with water during mining for roof support and to assist slurry pumping. Underwater cutting was enhanced with an air-shrouded water jet. Mined cavities were backfilled to prevent subsidence after abandonment. Roof subsidence during mining was avoided only when the cavity was filled with water. Environmental monitoring before, during, and after mining included hydrological studies and measurements of water quality. Significant water quality changes occurred only in the zone being mined and were confined to the immediate area of the borehole.

Jan 1, 1983

By F. E. du Plessis, P. De Waal

Through the development of innovative in-line mineral quantification sensors, the possibility has arisen to apply modern control theory to implement automatic process control for electrostatic high tension (“HT”) roll separators. A pilot-scale set-up was constructed to enable continuous tests to be carried out. A typical dry mill feed was continuously pre-heated and separated with a modern lab scale HT roll machine. The mineralogy as well as mass-flow of the non-conductor stream was quantified in-line, and the combined streams were re-circulated in an endless loop by a combination of vibration feeders and a bucket elevator. A fractional factorial experiment was executed to determine the most significant control parameters of the HT roll separator. Then a multi-input, multi-output dynamic model of the HT electrostatic separator was extracted by the application of standard system identification techniques for automatic control. The most important control variable to ensure a stable product grade could be identified. This allowed a robust single-input, single-output controller to be implemented. The process variable and set-point was mineral grade and the control variable was electrode voltage. Roll speed was manually adjusted while the mineral grade was kept on set-point by the control system. The roll speed, where maximum mass flow and therefore maximum yield was produced on-grade, could therefore be rapidly determined. Atmosphere humidity and ore temperature served as disturbances. Some other adjustable parameters were kept constant during the experiments, namely feed mineralogy, splitter settings and feed rate. Delivery of maximum yield, with a controlled grade, can improve production while reducing the burden of complex manual tuning. Manual tuning previously involved coping with multiple parameters with uncertain cross coupling influences on the end result. Even the end result was typically only known after completion of mineral assays. Automatic grade stabilisation and yield optimisation for a HT roll separator bank requires in-line measurement of mineralogy and mass flow, as well as the implementation of a robust process control system.

Jan 1, 2005

The mining industry, like most other industries, has had a difficult couple of years. What are your thoughts on the industry?s direction in the next few years? I am bullish on our industry. There is no question in my mind that the quality of life we enjoy today is largely a result of our past successes in the minerals and mining sector. I am equally certain that the sustainability of that quality of life and the aspirations of the rest of the world to attain that same level of lifestyle will depend hugely on our future successes and will be the driver for our industry to continue to excel and prosper. Surely, there are going to be challenges along the way. These challenges are not only from the public, regulators and various governing bodies, but also from our industry?s own self regulating efforts. However, we have demonstrated throughout the past several decades that we have the capability to meet these challenges head on and come out ahead.

Jan 3, 2010

By Dominick Mandalari, David Mast, Heather Ullinger, Juan Granja, Amanda Foote

The City of Akron will construct the Northside Interceptor Tunnel (NSIT) project to control and reduce combined sewer overflows. One component of the project a large diameter tunnel diversion / flow control structure that will facilitate tunnel storage, divert dry weather flow to the treatment plant, and divert large wet weather events that are greater than the tunnel capacity to the Cuyahoga River. The structure is designed to pass up to 1.2 billion gallons per day of flow and includes floatables screening. This paper will discuss project background, factors that influenced shaft location, and options evaluated to manage the large design flows.

Jun 23, 2024

By A. Habibi

A study has been undertaken on two 1.12 m diameter industrial booster fans operating under different blade settings powered by a 1200 rpm motor at the Missouri University of Science and Technology. The fans total pressure varies up to 1kPa forcingup to 25 m3/s through the workings. A pressure-quantity survey has been conducted inby and outby the booster fans with different blade settings. The study uses a variable speed drive (VFD) to determine the effect of rotational frequency on the system. The pressure drop across the bulkheads has been monitored during the experiments. The fans were operated with various blade settings to determine the optimal scenario that maintains the maximum airflow quantity and the lowest power demand at a particular ventilation station. Five scenarios were conducted with different blade setting and mostly with two different speeds. The experimental results show that alteration of fans? speeds by use of a VFD unit can reduce power consumption while maintaining airflow requirements. With the flow rate forced through the mine by the surface fan the blade settings 4 and 5 were determined as possible alternative for the mine ventilation system. In scenario 4, the airflow at the particular ventilation station for a number of speeds is over 20m3/s. The power consumption at 1080 rpm was measured to be 20.1 kW compared to 25.5 kW at 1200 rpm. The operating cost would be significantly less at lower speeds. Scenario 5 is the alternative making use of both booster fans and the main fan in series that meets the minimum airflow requirement at the particular ventilation station along with minimum power consumption. Reducing both booster fans speeds to 1054 rpm results in power consumption of both together dropping to 11.8 kW. Therefore blade setting 5 using two booster fans was determined to be the optimal setting. Separately it was determined that the combination with use of only one booster fan, the West booster fan, running in series with the main fan is the overall optimal scenario. The power consumption of the West booster fan was calculated to be 8.8 kW at 860 rpm with the minimum airflow requirement being met. Computational fluid dynamics is used for analyzing three dimensional flow structures in time domain and calculating the corresponding unsteady pressure fluctuations. The sliding and dynamic mesh techniques were used to study the unsteady flow interaction arising due to the rotation of the fan blades. The numerical predictions of the variables in the form of velocity vectors and contour plots detailing the flow characteristics are then analyzed according to the known physical situation and existing experimental data.

Feb 27, 2013

By Hasan Sevim

This paper summarizes recent developments in modeling of underground coal slurry haulage networks for determination of optimum design and operating parameters. The model presented here is based on a stochastic dynamic programming formulation, applicable in any typical room-and-pillar and/or longwall mining configuration commonly practiced in the United States. The formulation and the structure of the model is general enough to handle design problems involving more than one face and mining method. Given the stochastic operating characteristics and a system layout, the model can be used to determine the equipment configuration and operating regimes that minimize the overall unit cost of coal haulage.

Jan 1, 1983

By Steve J. Czehura

The Butte quartz monzonite is the host rock for early porphyry copper style mineralization and subsequent mesothermal-epithermal, enargite-gold style veining that transects the district. The east-west Anaconda system veins sustained mining for over a century. They include the Emma, Anaconda-Original, Syndicate, Badger-State and Alice-Rainbow veins, each with strike lengths of more than 3,660-m (12,000-ft) and vertical continuity in excess of 1,370-m (4,500-ft) with mining widths from 1.5- to 15-m (5- to 50-ft). These characteristics are unique to Butte. The incredible dimensions and tenor of these veins have yet to be surpassed and Butte is still touted as being the “Richest Hill on Earth.” The Anaconda Company was formed in 1895 to develop underground copper reserves in the district. It eventually consolidated all operations under one company. Production from underground mining continued through the mid-1970s. Openpit mining in the Berkeley pit began in 1955 with the extraction of supergene ores, along with the remnants of deeper horsetail zones inaccessible to the underground mines.

Jan 1, 2006

Scattered north and south along a 161-km (100-mile) stretch of Interstate 80, Newmont Min¬ing Corp. owns four active mining properties in Nevada?s northern high desert ? Carlin Trend Operations, Midas, Twin Creeks and Phoenix. Among the four, there are nine openpits, five underground mines and 14 processing facilities. While gold is the predominant ore, silver and copper are also produced. And in a move to hold down energy costs, Newmont built and owns the 200-MW (net), coal-fired TS power plant. This plant provides about 65 percent of the power used for Newmont?s own operations, while the rest is sold to NV Energy, which services Nevada and northeastern California. Bringing the Phoenix Mine ? Newmont?s newest in Nevada ? on-line presented many developmental and operational challenges. Located about 19 km (12 miles) southwest of the town of Battle Mountain, the general area had been home to prospectors and other mining companies since the 1860s. But any profitability in developing the lower grade gold, copper and silver deposit at Phoenix proved elusive, with Battle Mountain Gold being the last company to make an attempt. When Newmont acquired Battle Mountain Gold and its Phoenix reserves in 2001, the lower grade of ore was not a deterrent. Newmont found Nevada-wide cost savings synergies for maximizing profit during the depressed gold market of the late 1990s. The new property was aptly renamed the Phoenix Mine, a nod to its rising from the ashes of the dreams and efforts of previous mine owners.

Jan 2, 2010

By Warren E. Morrison

The expansion of the United States economy in the postwar period has had a tremendous impact on the demand for energy. Not only has total energy consumption increased at an unprecedented rate, but there have been major shifts in the composition or mix of energy resources within the end-use sectors. Because of the numerous interrelationships between substitutable energy resources and their markets, the energy economy can only be analyzed in terms of the trends of its component parts. This problem takes on additional complexity when attempting to chart the nation's future energy requirements. Total energy consumption can be forecast with reasonable accuracy for periods up to 15 years by relating this to projections of economic indicators. However, forecasting the component parts of the energy economy constitutes a dilemma in that the sum of the projected parts frequently exceeds predictions for total energy. Areas of uncertainty in energy forecasting tend to mount rapidly when proceeding from total energy to the consideration of specific energy resources consumed as fuel, power, or raw materials.

Jan 1, 1965

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal-mining operations can cause various disturbances to surface structures, ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of travelers, and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (such as decks, beams and abutments) are presented. A number of mitigation measures to protect bridge structures are recommended, along with an actual application case.

By R. M. Imhof, M. J. G. Battersby, G. Ciernioch

Pneumatic flotation is rapidly becoming accepted in the main stream of flotation techniques. Imhoflot is a pneumatic flotation process that in recent years has undergone progressive development. It combines short flotation times with excellent selectivity by employing intense pre-aeration and dispersion. K+S GmbH (K+S), Germany, has installed a complete Imhoflot flotation plant at its Sigmundshall plant. The plant treats hard salt consisting of sylvine, halite, anhydrite and kieserite. The reason for selection was that Imhoflot achieves the required grades of plus 60 weight percent K2O whilst offering lower operating costs than conventional flotation installations.

Jan 1, 2002

By M. Radwan, S. Shimada, S. Z. El-Tawil, K. A. El-Barawy, Y. Miyamoto

This study presents the results of synthesizing monolithic siliconoxynitride, Si2N2O, ceramic from a mixture composed of reclaimed silicon and natural desert sand by using the nitriding combustion synthesis method. Single-phase Si2N2O powder was prepared by the combustion of a mixture composed of silicon and pulverized sand in 3 MPa nitrogen gas. The combustion reaction completed in 2 min and the combustion temperature reached 1577°C.The as-synthesized Si2N2O powder is agglomerate of fine particles with sizes < 5 µm and has various morphologies; rod-like and irregular crystals, irregular kinking, hollow crystals and grown pseudo-hexagonal prismatic crystals. Porous Si2N2O compacts (24.5–47.1% porosities) were fabricated from the synthesized Si2N2O powder at different calcia-alumina additives (5–20 wt%) by normal sintering at 1500°C for 1 hr in N2atmosphere.They showed superior oxidation-resistance at high temperatures up to 1500°C in an oxidizing atmosphere of Ar/O2/H2O(70/20/10 kPa).Near-full dense Si2N2O compacts were also successfully fabricated from the synthesized Si2N2O powder with 5 wt% oxide additives by using the spark plasma sintering at 1600°C.DenseSi2N2O had good mechanical properties (18.7 GPa Vickers hardness, 3.3 MPa.m1/2fracture toughness and 363 MPa strength) and excellent chemical and oxidation resistance.

Jan 1, 2004

Global mining company achieves significant productivity gains with three-dimensional (3D) mine models developed with Abaqus finite element analysis software. In a steep change beyond traditional processes, Abaqus finite element analysis (FEA) software from Simulia (the Dassault Systèmes? brand for realistic simulation), is being used to enhance mine design and engineering simulation at a number of major mines around the world. In North and South America, Africa and Australia some of the world?s biggest mining companies are applying FEA technology to evaluate safety and improve design planning, implementation and operations. Beck Arndt Engineering (BAE), a Sydney-based international consultancy, is a pioneer in the commercial development of engineering solutions for the mining industry. The consultancy has worked closely with engineers at Simulia Australia to expand the use of Abaqus FEA simulation software for mining applications. Among the early adoptors of mine-ready FEA technology is the world?s largest miner, BHP Billiton. With BAE?s help, BHP has already applied this technology to evaluate mines in Canada and Australia. At the BHP Billiton Nickel West Perserverance Deeps Project in Western Australia, Abaqus FEA software is now being used to help engineer the safety and productivity of planned deep-mining operations. To achieve this goal in the deep-mining environment significant technological innovation is required. Using measurements of site deformation and seismicity, Abaqus FEA models have been calibrated and, in a single day, used to simulate a full, 3D, inelastic analysis of a mine?s life cycle. In recent years, similar applications at Debswana?s Jwaneng Mine in Botswana, the Newcrest Mining Ridge-way Deeps Project in New South Wales, Australia and Rio Tinto?s Argyle Diamond mine in Western Australia have also established Abaqus FEA analysis as the lead-ing technology for multi scale, simulation-aided mining engineering. Joop Nagtegaal, a pioneer of FEA and a Dassault Systèmes Corporate Fellow, said that Abaqus FEA software is unique in its capabilities to enable mining engineers to investigate design innovations from the drawing board to full production. ?In the design stage, Abaqus models, which include rockmass volumes spanning several kilo-meters around the ore body and down to excavations just a few meters across, are used to compare and optimize engineering options,? Nagtegaal said. ?Then, as the mine goes into production, large volumes of data from the field are incorporated with the analysis models to allow them to be calibrated to a precision not previously available to the mining industry.?

Jan 1, 2009

By J. Morris

Petro-diesel is a common collector for fine coal froth flotation but partitioning of diesel range organics (DROs) in process streams has not been widely studied. Preliminary research suggested that under normal dosing schemes total residual DRO in process waters should be limited to the sub-ppm water-soluble fraction (WSF). Further, polycyclic aromatic hydrocarbons (PAHs) should partition proportionately with DRO. The purpose of this study was to confirm these findings in laboratory flotation tests. Total DRO and specific PAHs were measured in tailings and concentrate streams, and coal recovery and ash rejection were tracked. Results show that concentrate waters consistently had higher DRO than tailing waters, and DRO in both streams generally increased with increasing diesel dosage. DRO again appeared to be limited to the WSF and PAHs tended to partition proportionately with DRO. Results indicate optimal flotation performance should generally coincide with minimal DRO partitioning to process waters. Under typical operating conditions residual DRO should not present an environmental concern; however, conditions should be avoided that allow significant overdosing of diesel.

Feb 23, 2014

By Karl R. Zipf

A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine. The gas samples are drawn via vacuum pump to the surface and are typically analyzed for oxygen, methane, carbon dioxide and carbon monoxide. Results of the gas analyses are displayed and recorded for further analysis. Trends in the composition of the mine atmosphere, such as increasing methane or carbon monoxide concentration, can be detected early, permitting rapid intervention that prevents problems, such as a potentially explosive atmosphere behind seals, fie or spontaneous combustion. TBS is a well-developed technology and has been used in coal mines around the world for more than 50 years. most longwall coal mines in australia deploy a TBS, usually with 30 to 40 monitoring points as part of their atmospheric monitoring. The primary uses of a TBS are detecting spontaneous combustion and maintaining sealed areas inert. The TBS might also provide mine atmosphere gas composition data after a catastrophe occurs in an underground mine, if the sampling tubes are not damaged. TBSs are not an alternative to statutory gas and ventilation airflowmonitoring by electronic sensors or people; rather, they are an option to consider in an overall mine atmosphere monitoring strategy. This paper describes the hardware, software and operation of a TBS and presents one example of typical data from a longwall coal mine.

May 1, 2013

By R. E. Ray

Compared to conventional fully ducted axial and centrifugal fan systems, jet fans can offer a number of advantages for control of smoke during fire emergencies and dilution of diesel engine exhaust products in vehicular and rail tunnels. The success of jet fan applications is the result of a balance between the temperature de-rating of the fan, buoyancy forces and the installation momentum transfer efficiency. This paper provides a case study of a unique application of vertically-mounted jet fans in ventilation shafts used to provide both emergency ventilation and pollution control for an overbuild created by the construction of a series of commercial high-rise residential buildings over a portion of an existing passenger rail line. A detailed evaluation of a set of shafts for one building is presented, including a discussion of the calculation methods used to estimate the required jet fan capacity and the results of the subsequent numerical analysis using Computational Fluid Dynamics to simulate the performance of the jet fans during train car fire emergencies.

Jan 1, 2009

Coal bursts are one of the least understood yet the most critical hazards in underground coal mines. The ground motions induced by seismic events can trigger unstable failure of coal and rock mass and degrade the surroundings of an excavation. Therefore, the characteristics of ground motions should be fully investigated for an improved burst risk management. This paper analyzes ground motion features of a longwall panel from a typical underground burst-prone coal mine in China. The results showed that most of the ground motions on roadways were hardly initiate coal bursts due to insignificant energy input to the damage. The intensity of ground motions in near-field zone were nearly 20 times higher than those in far-field zone. The strongest vibration on roadway was induced by a coal burst with energy of 28,600 kJ, which can cause ground motion of 0.77 m/s and equivalent dynamic stress of 14.69 MPa. The findings of this paper can improve the assessment of seismic risks and its management.

Jan 7, 2020

By C. Pattenden

The viability, self-reliance and resilience of small communities are perennial challenges in regional Australia. Recent developments in Australian mining regions seek to govern the minerals industry in a more holistic way that contributes to sustainable futures for affected communities in different contexts. In some areas of the State of Queensland land use conflicts and the cumulative impacts of multiple projects and activities across time and space have come to the fore. In more isolated regions of Western Australia the dominant issues relate to overstretching people, infrastructure and services in predominantly mining towns. In both cases, there is an ambition for regional towns with a strong extractive industry presence to transition into desirable, liveable and affordable cities with a diversified economy. The paper analyses two strategies - the Pilbara Plan in Western Australia, and the Sustainable Resource Communities Policy in Queensland - to identify how these governance instruments are contributing to sustainable development.

Jan 1, 2011

By D. Keech

The Conveyor Equipment Manufacturers Association (CEMA) specification B105.1 “Welded Steel Conveyor Pulleys” adequately defines standard pulleys for most aggregate material handling applications. However, many aggregate applications demand pulleys of higher capacity and reliability than that offered by CEMA pulleys. This paper examines the CEMA Pulley Standard and pulley specifications for aggregate applications requiring greater capacity and reliability than the CEMA Pulley Standard. Higher reliability increases the uptime and has a lower total cost of ownership.

Jan 1, 2003