Search Documents

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite [Bayer Process] is known as red-mud. Approximately, a ton of red-mud is produced for every two tons of bauxite mined. The red-mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that over 90-wt. pct. alumina can be recovered from red-mud by soda-ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of over 94 pct resulting in attempts for magnetic separation. These separations are desirable in the notion that there is no waste product generated from this type of processing and consequently an opportunity for complete utilization of the waste material. Conversely, the pre-separated material could be charged through the tuyeres in an iron blast furnace or smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag will be significantly high justifying its recovery by established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red-mud as an alternative to direct-reduced iron [DRI] has also been discussed. Critical assessment of the recovery sequence chosen for the products has been described based on economics.

Jan 1, 2001

By M. S. Klima, A. P. Pinkerton

Solid-bowl (decanter) centrifuges are used extensively to dewater slurries in a wide range of industries. However, the application of decanters as classification devices is not as common. In this study, the performance of a continuous, pilot-scale, solid-bowl centrifuge was evaluated when classifying an ultrafine coal slurry containing nearly 60% material less than 10µm. The current study examined the effects of operating conditions on centrifuge performance. The test conditions included centrifuge bowl and scroll speeds, volumetric feed rates, solids concentration, and pond depth. Centrifuge performance was evaluated using partition curves, along with product yields and solids concentrations.

Jan 1, 2000

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification (nickel, cobalt, copper, and manganese) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte, ammoniacal leaching (gas reduction or Cuprion), and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stems from the 1970s and 1980s and is not always easily accessible. This paper will detail the series of tests conducted and provide updated results obtained (high Ni/Co/Cu recovery with limited Mn/Fe), as well as comment on the potential treatment options on the product solution and residue.

Feb 1, 2025

By Lawrence H. Roth

Past failures of coal refuse embankments have resulted in intensified efforts in inspections of coal refuse sites by the Mining. Enforcement, and Safety Administration (MESA). MESA inspections however, are mainly qualitative and are often time consuming, Therefore, in August 1975 CH2M HILL was awarded a contract to identify, develop, and test a rapid system for monitoring coal refuse embankments to aid in MESA inspections. The rapid monitoring system developed uses convergent and vertical photography from conventional fixed-wing aircraft. The system was tested on an active landslide and on two coal refuse facilities using both black and white and color infrared film. Field tests showed the system was capable of accurate measurement while providing qualitative data through photo interpretation. The accuracy of the system allows it to be used to monitor coal refuse embankments, tailings dams, major earth dams, and natural slopes. Based on CH2M HILL results cost for monitoring by rapid system was approximately 25 percent of cost by conventional ground survey.

Jan 1, 1980

By Clair Murdock, David Heath

The 1,280 MW Sir Adam Beck II Hydroelectric Project was constructed in the1950s, at Niagara Falls, Ontario, Canada. The twin intake tunnels total over 17 kilometers in length and pass deep below the City of Niagara Falls. The tunnels were excavated using drill and blast methods, with a top heading and bench approach. The shot rock was loaded with electric shovels and transported to the five shafts with off-highway trucks. The tunnel muck was hoisted to the surface by skip and transported by truck to disposal areas. The volume of underground excavation for the 15.55 meter diameter tunnels and the shafts exceeds 3,500,000 cubic meters, then and now the largest underground civil works excavation by drill and blast in the Western Hemisphere. The lining required over 900,000 cubic meters of concrete. All of this work was completed in three years, remarkable progress, considering the technology of the day, comparing very well with the rapid excavation and tunneling methods of the twenty-first century. Big, fast, and deadly—at least 20 lives were lost in construction accidents.

Jan 1, 2007

By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

A possible process for extracting tellurium and antimony from a residue generated in alkaline sulfide leaching of telluriumbearing alkaline skimming slag was proposed. The central composite design was employed to define the optimal leaching conditions for tellurium and antimony extractions from the residue sample. Using a 23 factorial matrix, the best performance for tellurium and antimony extractions (96.36% and 99.64%) were obtained at 175 g L−1 Na2S concentration for 80 °C during 60 min. The notable degree for influencing tellurium and antimony extractions was leaching temperature, Na2S concentration, and leaching time. The analysis of variance results indicated that the regression model was significant and suitable to be used for the optimization of independent variables within the range. The model was validated under optimal operating conditions based on the experimental design results. Antimony and tellurium in the leach liquor were separated and recovered by H2O2 oxidation followed by Na2S-Na2SO3 reduction. 98.93% of antimony was precipitated selectively during H2O2 oxidation, while 95.06% of tellurium was precipitated during Na2S-Na2SO3 reduction. NaSb(OH)6 and elemental tellurium was obtained as the product.

By Antonio Rivera

On Nov. 13, 1985, Colombia's Ruiz volcano erupted, killing an estimated 25,000 people and burying several villages. Damages were estimated to be about $US300 million. The following is an account by SME member Antonio Rivera of the volcanic activity that led to the eruption. His account also includes a description of the geography and some geology of the affected area. Mining operations in the area were mostly unaffected, although some operations were forced to close until the roads leading to them could be repaired. Introduction The Ruiz volcano is located on the Central Cordillera of Colombia about 28 km (17 miles) southeast of Manizales, the capital of the state of Caldas. Ruiz is one of nine volcanoes that form a complex volcanic chain within the middle portion of the Central Cordillera. The Cordillera has 30 other volcanoes in the southern part of Colombia. Ruiz volcano Ruiz's elevation is 5200 m (17,060 ft). It is covered by an ice cap estimated to be 20 m (66 ft) thick at its summit, an area that covers 17 km2 (6.5 sq miles). Drainage is composed of several rivers that flow into the Magdalena River on the east and Cauca River on the west. The rivers flowing to the east are Guali, Azufrado, Lagunillas, and Recio. The rivers that flow to the west are Claro, Molinos, and Chinchina. There is a road from Manizales to El Refugio, a ski area located on the northeast flank of the volcano at 4800 m (15,750 ft) in elevation. The Ruiz volcanic complex was built in two stages. The first is a shield type of volcano (mainly lavas) formed about a million years ago. The second is a younger stratovolcano overlaying the ancient one. It consists of lavas and pyroclastics and was built over the past 500,000 years. Twenty-four eruptions of Ruiz are known to have occurred during the last 14,000 years. Its products mainly consist of lava flows, pyroclastic flows, mudflows (lahars), and directed lateral explosions. Historic eruptive record 1595 - Debris avalanche, blast, pyroclastic flows, mudflows, ash flows, and ash fall. 1828-1829 - Ashes (phreatic). 1831-1833 - Gas emissions and ashes. 1845 - Mudflows and pyroclastic flows. 1985 - Sept. 11- Fumarolic activity, phreatic eruption, ash fall, and small mudflows. 1985 - Nov. 13 - Ash and pyroclastic fall, major destructive mudflows (magmato-phreatic eruption). From 1845 through 1984, Ruiz volcano always had a slight fumarolic activity. It was restricted to the crater area. In November and December 1984, the fumarolic activity increased and the first ash emission and vapor-sulfur formation started. Small local earthquakes accompanied these volcanic activities. The volcano had a small erup¬tion on Sept. 11, 1985. It was manifested by phreatic explosions that ejected fragments of the vent and formed ash deposits 25 mm (1 in.) thick around an area 2.5 km (1.5 miles) from the crater. Fine material was blown by the wind and reached Manizales and neighboring areas, producing a small layer of ash up to 10 mm (0.4 in.) thick.

Jan 2, 1986

By Harvey W. Parker

The underground industry is challenged by many complex technical and non-technical issues and risks. The most obvious of these are the traditional technical issues that we usually try to address with risk management techniques. However, there are many other non-technical risks that our projects face on a daily basis which we often fail to fully recognize or appreciate. This paper addresses some of the less-technical broad-based risks in order to put them into perspective with the technical risks we face day to day in underground planning, design and construction. The good news is that Risk Management techniques are not always about bad things. For obvious reasons Risk Management is always thought of in terms of the ?downside? of risk (i.e., the identification and mitigation of things that can go wrong). On the contrary, there is an ?upside? of things that might go better than expected. Fortunately, if a deliberate effort is made, the same principles and techniques that our industry uses in Risk Management can be applied toward identifying and quantifying the Opportunities and Benefits that might occur. In this way, the process of conducting risk management programs can not only identify the downside risk but can be used to identify and direct projects to take advantage of the upside of uncertainty (i.e., Opportunities as they arise). This beneficial aspect of risk management programs will be highlighted in this paper together with the importance of the non-technical issues.

Jan 1, 2008

In February 2001, Kalgoorlie Consolidated Gold Mines (KCGM) commissioned its first full-scale ultra fine grinding (UFG) plant to supplement existing roaster concentrate treatment capacity. This process involves the fine grinding of refractory pyritic concentrate to 10µm, followed by direct cyanide leaching for the recovery of gold. By this means gold is economically extracted from the concentrate without the need to first oxidise the host pyrite. This paper details the history of the project from initial laboratory testwork comparing possible treatment options, to current performance of the 12 tph plant. This includes the cost comparison of the major treatment options, the laboratory and pilot scale UFG performance, the UFG mill selection, cyanide leaching of UFG product, commissioning and plant performance to date.

Jan 1, 2002

By T. J. Lynch

A new class of polymeric dispersants for industrial minerals has been synthesized and evaluated. Currently available dispersants give initial low viscosities at high mineral loadings, however slurry viscosities can rapidly double or triple on standing over the first several days. The new dispersants give low initial viscosities that are more stable and maintain a lower viscosity for at least one month. The new dispersants are made possible by controlling the polymer molecular weight distributions during their manufacture such that essentially all of the dispersant is adsorbed onto the mineral surface, preventing depletion flocculation.

Jan 1, 2012

The La Colosa, Colombia porphyry gold deposit is currently in the pre-feasibility stage. This large deposit has many types of gold mineralization: native gold, electrum, and tellurides. These variations in the gold mineralization lead to variability in the gold recovery. The final process flowsheet may include gravity concentration with cyanide leaching. Metallurgical testwork is utilized to identify the zones of ore that may be problematic to recover. To help select the samples that represent the fluctuating variability zones, geometallurgical models are constructed using mineralogy and geology data. These zones are then wireframed and compared to the geological and structural models for spatial correlation. Samples for the variability testwork will be selected from these different zones to identify and analyse the effect the different gold mineralization types have on the recovery. By using geometallurgy to aid in the sample selection for metallurgical testwork, the variability in the ore body can be understood and constrained to aid in process optimization.

Feb 27, 2013

By Key Rosebrook, Jennifer Laggan, Ashley Rivera

Significant quantities of waste rock at abandoned uranium mine (AUM) sites in the western United States require removal from steep slopes exceeding 45 degrees in remote locations. This prevents the use of traditional excavation equipment and poses significant challenges for safe, effective material removal. A pilot study was conducted using a spider excavator to demonstrate the feasibility of removing waste rock and transporting it to areas where conventional equipment could be employed. The spider excavator was evaluated for its effectiveness in excavation, material movement and control, container usage, dust mitigation, and ensuring human health and environmental safety. The study established constructability and engineering parameters for implementing spider excavators in these challenging environments. Key outcomes include the preservation of existing vegetation, improved waste movement control, and enhanced safety measures for workers, nearby residents, and the environment.

Feb 1, 2025

By Xiaodong Ma, Marek Pawlik

Introduction Guar gum is a natural nonionic polysaccharide. Guaran, the functional polysaccharide in guar gum is a chain of (1?4)-linked ß-D-mannopyranose units with a-D-galactopyranose units connected to the mannose backbone through (1?6) glycosidic linkages. The poly-mannose chain is randomly substituted with galactose units at a mannose-to-galactose ratio of 1.8-1.0 [1]. Cheng et al. reported that the molecular weight of natural guar gum is 1.935 • 106 [2]. Robinson et al. found that the molecular weights of five grades of commercial guar gums ranged from 4.4 • 105 to 16.5 • 105 [3]. Guar gum is frequently used as a depressant of naturally hydrophobic gangue minerals (e.g. talc) in the flotation of PGM-bearing ores, and according to Harris et al. a wide variety of modified guar gums are available for this application [4]. The Canadian potash industry utilizes natural guar gum as a blinder of water-insoluble slimes in the flotation of potash (sylvinite) ores, a process that is carried out in a saturated KCl/NaCl brine. The role of the polysaccharide is to prevent a primary amine collector from adsorbing onto these unwanted fine minerals. Hydrophobic interactions between basal cleavage planes and the polymer appear to be involved in guar gum adsorption on talc [5,6]. Liu and Laskowski stressed the importance of metal impurities on mineral surfaces that can serve as the active sites for polysaccharide adsorption [7]. This postulate was consistent with the later observation that, in addition to hydrogen bonding, the adsorption of guar gum onto talc was strongly dependent on the surface concentration of magnesium sites [8,9]. In this case the adsorption process was visualized as metal-polysaccharide complexation facilitated by the cis-configuration of the hydroxyl groups of mannose monomers. Hydrogen bonding and chemical interactions with metal sites were also suggested by Rath and Subramanian in their studies on guar gum adsorption on biotite mica [10]. In a recent study, Wang et al. demonstrated that hydrogen bonding is the main driving force behind guar gum adsorption onto talc [11]. Their data also show that the adsorption density of guar gum on alumina is about five times lower than the adsorption density on talc. Pawlik and Laskowski reported that the amount of guar gum adsorbed on illite was independent of ionic strength over a wide range of salt concentrations [12]. The adsorption density of the polysaccharide on illite did not measurably change with ionic strength from that of distilled water to about 50%-saturated KCl/NaCl potash brine (~3N KCl/NaCl). However, guar gum adsorption on dolomite dramatically decreased over the same range of ionic strengths, and no reliable explanation of that phenomenon was proposed [12]. The water structure-breaking or structure-making capabilities of background ions are usually ignored when discussing adsorption mechanisms of polymers. The concept of “structure breakers” and “structure makers” was first introduced by Gurney, and Frank and Wen who postulated that each ion is surrounded by three distinct regions of water structure [13,14]. In the first layer, water molecules are tightly bound to the ion. The second region extends farther away from the ion and is referred to as the region of structure breaking. Only at larger distances, where the ionic field is weak, water molecules form the “normal” ice-like structure. It is also now recognized that the first layer can be further divided into the primary and secondary hydration shells. Small, strongly hydrated ions reinforce the “normal” structure of water and the region of structure breaking disappears. In contrast, large less-hydrated ions disturb the ice-like structure and generate an extensive region of structure breaking. Experimentally, these two effects can readily be distinguished through viscosity measurements. Increasing concentrations of structure-breaking ions result in a decrease of the viscosity of aqueous solutions. On the other hand, increasing amounts of structure-makers significantly reduce the viscosity of water. Alkali metal cations form a sequence known as the Hofmeister series. The Hofmeister series - Cs+, K+, Na+, Li+ - orders the cations from the least hydrated to the most hydrated. Based on literature viscosity data for aqueous

Jan 1, 2005

By A. Warren Wilson, Hugh R. Wilson

This paper describes the evolution of the Waste Management Program at the Lupin Mine through the years 1982 - 1986. Echo Bay Mines' Lupin Mine is located on the western shore of Contwoyto Lake in Canada's Northwest Territories about 80 km. south of the Arctic Circle. The gold mine commenced production in 1982 and the Waste Management Program was based originally on the total containment concept. Due to an expansion of the mill circuitry and increased throughput, it was apparent that total containment was no longer applicable and therefore studies were undertaken to characterize the tailings, to evaluate the effectiveness of natural degradation of contaminants in the tailings pond and to determine what additional treatment steps would be necessary to meet the requirements of the mine's Water Licence. These studies indicated that arsenic and cyanide concentrations in the tailings pond decant water would not meet Water Licence discharge limits unless certain measures were under taken. As a result of this work, in late 1984 a decision was made to create a two-ponds-in-series system and the necessary civil work was started in 1985. In addition, a series of dykes were constructed to contain the solids portion of the mill tailings in a confined area of the first pond. To remove cyanide, the ponds are operated in a sequential fill and decant mode to take maximum advantage of natural degradation. For arsenic removal, a chemical feed system was constructed for iron salt addition to the decant stream from the first to the second pond. Decanting of the ponds is accomplished by means of a series of 500 mm (20 inch) Sclairpipe syphons.

Jan 1, 1987

By Alexander N. Winchell

"Location. The copper mines of Michigan are all in the northern part of that state on the Keweenaw Peninsula, which extends from the (Michigan) mainland for about seventy miles northeasterly toward the middle of Lake Superior. The mines occur in a belt or zone occupying the central portion of the peninsula from end to end.. The most productive mines for many years past have been those located not far from the city of Houghton in' the central part of the zone, in a section extending about ten miles southwest of Houghton and fifteen miles northeast. The most important mines in order of location, from the northeast to south¬west, are the following: Mohawk, Ahmeek, Allouez, North Kearsarge, Wolverine, South Kearsarge, Centennial, Calumet. and Hecla, Osceola, Franklin, Quincy, Hancock, Isle Royale, Superior, Baltic, Trimountain, and Champion. The first three named are in Keweenaw county and all of the others are in Houghton county. Still farther to the southwest are the Lake, Mass, Adventure, Michigan, Victoria, and White Pine mines. These are in Ontonagon county.History. The exploitation of these copper mines extends back into prehistoric times. There is little evidence that the American Indians carried on mining operations in this region in the period shortly before the advent of white men, but there is abundant evidence that the ancestors of the Indians, •or some earlier inhabitants of the region, carried on primitive mining operations. For example, Mr. S. O. Knapp, Agent of the Minne¬sota Mining Company, in the winter of 1847-48, made the first discovery of prehistoric mining. This event is described as follows by Foster and Whitney :"

Jan 1, 1920

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

By A. Habibi

The ventilation survey was conducted in an underground longwall trona mine. The mine is relatively shallow and categorized as a gassy mine. The ventilation system consists of nine shafts (three intakes and six exhausts). Three surface based axial fans ventilate the mine configured in a blowing arrangement. Following the ventilation survey airflow quantity, frictional pressure losses and air psychrometric characteristics have been quantified. An accurate resistance survey has been conducted to calculate the pressure drop with regard to moving cages and skips in the shafts. This paper discusses the benefits of utilizing high accuracy digital pressure transducers and psychrometers in a ?leapfrogging? survey to gather data needed to build the computer ventilation model. Two underground booster fans with VFD are currently idle but available at the mine. The ventilation model has been used to determine the optimal booster fan locations to decrease the overall operating cost by reducing the load carried by the main fans. A leakage study has been conducted to evaluate the effects on the system of additional pressure from a booster fan. The study finally prepares a future ventilation model for the next fifteen years of mine operation and investigates the effect of proposed scenarios.

Feb 27, 2013

By Paul D. Tomlingson

Modern production equipment has been designed with greater productive capacity and higher reliability to meet the rigorous operating demands of the mining industry. These improvements have also made the equipment more complex and challenging to maintain. Whether these equipment enhancements contribute to more effective mining operations depends on the overall quality of maintenance. Maintenance is not a stand-alone activity. Although its quality depends primarily on maintenance, cooperation and support from other departments, coupled with the skillful guidance of mining managers, greatly influence maintenance success. Therefore, maintenance risk management must look beyond maintenance itself. Successful maintenance risk management begins with an assessment of the maintenance-related interactions of all mining departments within the mine’s stated operating strategy.

Jan 1, 2005

By E. A. Adey, C. Baciu, P. Whitbread-Abrutat, M. Varul, T. Ejdemo, R. K. Shail, F. Wall

Responsible mining requires stakeholder engagement throughout all operational stages and after mine closure. By assessing the current and anticipated future socio-economic and environmental impacts, a company can maximise the positive impacts they can have on a community, whilst minimising any negative impacts. Despite the current emphasis on companies maintaining effective stakeholder relations to gain their ‘social license’ to operate, findings of the present study reveal a wide variation in community expectations, with different degrees of ‘acceptability’ evident across seven sites in Romania (Rosia Montana), Sweden (Kristineberg), the United Kingdom (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These variations reflect the current status of mining within a community, as well as its socio-economic background and the nature of existing engagement with mining companies already operating in the region.

Jan 1, 2011

Many of the world?s largest existing mines are considering substantial step changes in production volumes, compensating for declining ore grades while trying to address increases in world demand for resources. The natural configuration of coal deposits allows for many mine development openings along the strike to access the ore body and thus increase volume. Similarly, with iron ore the nature of the deposits means that additional capacity can easily be added by opening up new mesas and providing extensions to infrastructure. On the other hand most of the non-ferrous metaliferous deposits form vertically and additional extraction volume comes from increasing depth. Underground mining from the base of the strata allows for large extraction rates, but block or panel caving operations develop at rates dictated by the geophysics of the overlying strata and the need for massive tunnelling developments to establish sufficient extraction points for high volumes. For really big mine production capacity, open cast mining still allows the easiest development of more massive mining techniques. But there remains the question of whether there are limits to how large an open cut mine can become in terms of throughput?

Feb 27, 2013