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By Amila Sandaruwan Ratnayake, T. Dilmi. U. Wijewardhana, H. C. S. Subasinghe

The value addition potential of ilmenite was examined using several characterization techniques. Raw ilmenite is composed of 93.65 wt.% of FeOTiO2, 3.55 wt.% of SiO2, 1.22 wt.% of Al2O3, and the remainder being other minor oxides. Ilmenite and powdered carbonized coconut shells were mixed in the weight ratio of 4:1. A separate fraction of the same mixture was added with powdered seashells in the weight ratio of 4:1:0.5. Six fractions of each mixture were distinctly milled from 1 to 6 h in a planetary ball mill. XRD spectra (broadened and diminished reflections of ilmenite) and FTIR observations (Ti―O―Cbonding) of milled samples indicate the possible incorporation of carbon into the ilmenite structure. Any clues of an occurrence of new rutile peaks were not observed in XRD spectra of milled samples. Consequently, the carbothermic reduction has not been initiated during mechanical activation. In this case, samples powdered for 6 h in a mill were isothermally annealed for 2 h under normal airflow at temperatures of 800 °C, 1000 °C, and 1200 °C, respectively. According to the X-ray diffractograms, the annealing temperatures of 1000 °C and 1200 °C exhibited almost similar trends with rutile (R), pseudobrookite (PB) and elemental iron (F), and a very few ilmenite (I) peaks. Consequently, 6 h of milling and 1000 °C annealing were concluded as the optimum conditions for the carbothermic reduction. Moreover, this study indicated seashells as a potential rate raiser for the carbothermic reduction of ilmenite at 800 °C. Therefore, this process is applicable to upgrade ilmenite into a mixture of synthetic rutile and elemental iron.

Mar 29, 2021

Lack of selectivity in mixed mineral flocculation can be attributed to one or more of the following factors: dissolved ion interference, heterocoagulation, mechanical entrapment in flocs and entrainment of fines between flocs. In a study of apatite- dolomite system, it was determined that dissolved ions do not have a significant effect on selectivity. Heterocoagulation was minimized by choosing proper process conditions and addition of a dispersant. Mechanical entrapment was proved to be insignificant and efforts were made to reduce entrainment by choosing an appropriate method of separation of flocs from fines. A new factor termed "polymer induced entrapment" which occurs due to limited affinity of the polymer to the mineral which is not flocculated is postulated to be the cause for the loss of selectivity.

Jan 1, 1986

By G. A. Gruber

A flotation process has been developed to successfully treat ore from the Santo Domingo phosphate deposit in Baja California Sur. The ore contained less than four percent P205 with quartz, silicates, and carbonates as gangue minerals. Flotation of the low grade feed In sea water required that the conventioinal Crago Process, comprising direct anionic flotation, deolling, and inverse cationic flotation be augmented by an anionic cleaner flotation step, phosphate depression, and a calcite flotation step.

Jan 1, 1986

By R. Yang

This paper presents a kinematic approach for blast modeling with examples of blast models that were developed previously. A kinematic approach was applied successfully in developing blasting models that can simulate all blast design parameters for field applications. Several applied blasting models have been developed and applied widely in the world. A kinematic approach to blast modeling refers to using measurements of kinematic quantities such as the velocity, strain, or displacement and well-established assumptions to model blasting phenomena, rather than being restricted to use first principal of physics, such as, the stress- and material-constitutive relations. The kinematic quantities are easy to measure in the field. Due to the complexity and inhomogeneity of rock mass properties, using first principles of physics, many parameters of rock and explosive properties must be involved, which are hard or impossible to quantify. This creates a major impediment when trying to simulate the total process of blasting based upon first principles of physics. The 3D kinematic model for muckpile formation was developed and applied to open pit blasts. The multiple blasthole fragmentation model developed during recent years has been applied successfully to many mine sites around the globe. These models are typical examples of blast modeling using the kinematic approach, which enables the models to catch major trends of the blasting process and explicitly simulate full blast design parameters and complex geometries. Blast modeling using the kinematic approach results in easy model calibration and validation against field measurements and effective applications to practical problems. Using kinematic models of the muckpile formation and the multiple blasthole fragmentation model, this paper demonstrates the merits of the kinematic approach for blast modeling. New developments of the models were also presented in the paper, which illustrate the potential of the kinematic modelling approach.

Mar 2, 2022

By A. G. Fonseca

The effects of coal cleaning, coal combustion and flue gas particulate removal systems on the partitioning of 12 trace elements were investigated. This study was prepared to help document the fate of trace elements in modern coal preparation plants and coal-fired utility boilers. The coal cleaning data were obtained from several coal preparation plant operations. The CONSOL 1. 5 MM Btu/hr pilot combustion and electrostatic precipitator (particulate removal system) test facility was used to develop the combustion systems data. A comparison with the very limited amount of published data from utility boilers is presented.

Jan 1, 1993

By E. Giama, A. Macridis, A. M. Papadopoulos

ISO 14031 is an international standard that describes a process for measuring environmental performance evaluation by setting quantitative indicators and providing a structured approach for organizations to follow, independent of location, size, complexity and type of activity. It is not a standard for certification as ISO 14001 is, but it fits into the ISO 14000 series of standards and is intended to assist organizations to apply environmental management systems and obtain environmental evaluation. This case study’s main objective is to identify the interaction between ISO 14031 and ISO 14040-42. ISO 14040-42 is referring to Life Cycle Analysis (LCA) methodology. More specific, LCA is applied (based on the ISO 14040-42 standard) to stone wool’s production, the market dominating thermal insulation material, produced by bauxite and amphibolite. LCA is used as a decision making tool for the development of environmental indicators (based on ISO 14031 guidelines) and for environmental performance evaluation.

Jan 1, 2005

By Franz Wilhelmstoetter, Christian Karner

"The Confederation Line is phase one of Ottawa’s light rail transit, which consists of 13 stops and stations. The project’s center piece is a 2.5 kilometer (1.6 miles) long tunnel with three underground stations leading underneath downtown Ottawa and is constructed within feet of adjacent buildings. The downtown stations, Lyon and Parliament, are caverns approximately 16.5 m (54 ft) by 18 m (59 ft) in a horseshoe configuration constructed in rock, while the third station, Rideau, is approximately 22 m (72 ft) by 18 m (59 ft) in an oval configuration and constructed in mixed ground. The paper will discuss design decisions made early on in the project such as excavation method, unique construction sequencing, and equipment selection, and go on to include corresponding progress rates. The paper also documents design and construction challenges of large caverns in very close proximity to existing buildings and varying ground conditions. Finally, an overview of achieved construction milestones and a current construction progress will be presented. Station cavern excavation is expected to be completed in early 2016. INTRODUCTION The number of urban metro construction projects has certainly increased over the last decades. Cities are growing rapidly all over the planet and many are striving to keep up with the increased demand for public transportation. One of the most feasible types of inner-city transportation with the capacity for large quantities of passengers are metro (subway) systems. Still, large construction projects in dense urban areas often affect the city’s residents in mostly negative ways. During construction, residents face the obstacles of road closures, noise, dust, economic loss for businesses, and property value losses are common. In other words, individuals are directly affected by the way new infrastructures are planned, designed, built and operated. The tunneling industry offers unique opportunities of keeping these side effects to a minimum and possibly avoiding them all together. Although challenged by a variety of constraints (some of which will be discussed in this paper), urban tunneling applications offer a chance to keep cities environmentally, economically, socially, and culturally sound during construction."

Jan 1, 2016

By E. H. Cho

A current environmental concern is the cleanup and restoration of soil contaminated with low-level radionuclides at DOE sites including the Nevada Test Site. At the present, there is no applicable process to economically and effectively deal with the remediation of contaminated soils. This situation requires development of a selective flotation process to separate the radionuclides from contaminated soil efficiently and economically. In this study, a minus 200 mesh size fraction of pure cerium dioxide was used as a surrogate for plutonium oxide which is the major contaminant at the Nevada Test Site. A Hallimond flotation cell was utilized to examine the flotation behavior of cerium dioxide with oleic acid under various conditions of pH and collector concentration Mechanical cell tests were conducted to float the surrogate from a mixture with uncontaminated Nevada Test Site soil in the absence and presence of calcium carbonate as a carrier. Two different sizes of the carrier (minus 150 mesh and 65-150 mesh) were tested. It was found through the Hallimond cell flotation tests that the cerium dioxide could be floated well at pH's 4 and 9 with 10-3 molar oleic acid. It was also found that the addition of the carrier drastically enhanced the flotation recovery of cerium dioxide. The flotation recovery of the surrogate increased from 34 % to 65 % by adding only 0.5 % calcium carbonate (minus 150 mesh) in the feed and also increased to 95 % by adding 10 % of this carrier to the feed. The finer size fraction of calcium carbonate (minus 150 mesh) was more effective in recovering cerium dioxide than the coarser size fraction (65-150 mesh) The flotation method utilizing a carrier of calcium carbonate seems to provide a high potential to be used for the remediation of soil contaminated with radionuclides at various Department of Energy's nuclear weapon sites.

Jan 1, 1996

By D. Kozelj

Introduction The porphyry copper deposit “Borska Reka” is the biggest undeveloped deposit in the Timok Magmatic Complex (TMC). Total reserve calculated manually is 611 Mt (cut-off grade 0.3% Cu) of 0.62% Cu, 0.21 g/t Au and 1.81 g/t Ag and 869 Mt of 0.58% Cu, 0.14 g/t Au and 1.11 g/t Ag using software. But since several deep drill holes are suspended in high grade (0.7% Cu) porphyry, total reserves could exceed 1Gt. The massive sulfide is also detected in the central (12 m at 4% Cu) and the bottom of porphyry style. Deposit was discovered during geologic exploration of deeper part of the Bor copper and gold deposit, i.e. area of high sulfidation with dominant massive sulfides. During exploitation of massive sulfide, constant explorations were carried out aimed at the expansion of reserve and discovery of new ore bodies. In that way, porphyry copper mineralization was discovered without knowing in the beginning that it was different mineralization type in regard to the ones that had been already identified and exploited. Vertical extension of porphyry is 0 m up to -1000 m sea level and not contoured along plunge. In the very beginning (1976), the exploration was focused on the shallow part of porphyry. That is because block caving method of massive underground mining was not developed at that time. Up to 1999, most of activity was related to underground exploration up to level -395 m. Geographic position The Bor deposit is located close to the industrial and University town Bor, which has over 50,000 inhabitants (census made in the year 2002). Apart from the Bor Mines, industrial complex of Mining & Smelting Basin Bor (RTB) comprises also a copper smelter (installed capacity up to 160,000 tons of blister copper) and tank house, copper wire factory, copper tube factory etc. Currently, RTB Bor is under privatization process that is going to be completed by the end of 2006. Up to date, over 20 companies have bought tender documentation.

Jan 1, 2007

By D. F. Scott

Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions, and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep (> 1220 m) underground pillars. If high-stress areas are detected, they can be destressed prior to development or avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient, and non-invasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.

Jan 1, 1997

By David Kwietnewski

Roadheaders are gaining widespread acceptance in North America as a means for mechanical tunnel excavation. Until recently, almost all of the large-scale North American tunnel projects were excavated one of two ways ? the tried and true drill-and-blast method or with the use of tunnel boring machines (TBM), the hi-tech super-excavators. TBMs enjoyed fast-growing popularity worldwide as TBM manufacturers offered greater technology to meet the demand of the civil tunnel industry in the late 20th century. Recently, though, more tunnel projects, large and small, can thank the brute force of a roadheader for getting the job done.

Jan 1, 2011

By Karin Bäppler

Hydropower produces almost two-thirds of the world’s renewable electricity generation and delivers a major contribution on the ambition of the Paris Agreement and Sustainable Development Goals (SDG) with a range of benefits to society and environment. These include clean and flexible generation and storage in addition to reduced dependence on fossil fuels and avoidance of pollutants. The Limberg III PSP is one of the European projects that addresses the implementation of the UN SDGs. The challenge of the project is the construction of a 770 m long pressure shaft to be excavated with a TBM at an inclination of 42°.

Jun 13, 2023

By Joseph J. Feiler

Historical mining operations in Colorado and other western states have resulted in thousands of remnant mine openings. Many are sources of metals loading and acid water generation in surface and ground waters. It is estimated that more than 965 km (600 miles) of streams in Colorado have been impacted by past mining activities. The Animas River watershed in southwestern Colorado is one of the most heavily affected areas in the state. Abandoned mine features pose significant safety hazards to those who enter them. These hazards can include bad air, unstable rock or falls into open shafts, stopes and winzes. Backcountry skiers and snowmobile enthusiasts are particularly vulnerable to falls into snow covered mine openings.

Jan 1, 2006

By K. Awuah-Offei

Energy efficiency has become significant due to cost and environmental considerations. Comminution and material handling have been identified as the two most energy intensive processes in mining. The objective of this work was to evaluate truck-shovel energy efficiency strategies using discrete event modeling. Energy audits and time and motion studies were conducted at a surface coal mine to acquire data. A discrete event simulation model of truck-shovel operations was built in Arena® and validated with the field data. The model was used to evaluate the effect of using a larger shovel, and optimizing truck-shovel matching on fuel efficiency. The results indicate that using a larger excavator increases the fuel efficiency of the operation while optimizing truck-shovel matching does not. However, using a larger shovel will lead to under-utilization of the shovel. This work shows the potential benefits of using discrete event simulation to model energy efficiency of mining operations.

Jan 1, 2012

By R. Fuenzalida

Since 2007, a number of Multivariable Predictive Control (MPC) Applications have been implemented on SAG mills, among others, within the Kairos Mining Concentrator Automation Program using ?Profit Controller?? and other tools comprising the ?Profit Suite??. Along this journey, several interesting and challenging issues related to SAG mill operation and control have been faced, which are relevant to be shared with the Mineral Processing community. These advanced control applications have an operational objective whose goal is to increase marginal profit on the concentrator, together with increasing mill stability. In regard to this objective, the issues to be presented and described are in direct relationship with ?Profit Controller? features and the SAG role; they are also stated and linked to get the most of the mill. Some conclusions and findings are also presented, leading to recommended practices on how to use the controller. These findings have also lead us to decide further actions to be taken on new applications to deploy and also on devising and implementing some complementary components to increase robustness of the overall automation solution, as well as reducing the need for operator intervention.

Jan 1, 2012

By Donald L. Everhart

The National Uranium Resource Evaluation (NURE) program since 1974 has been designed to accomplish a comprehensive coverage of the 48 conterminous States and Alaska to evaluate the total uranium resources of the USA. This resource base includes both ore reserves and potential resources. Techniques include airborne radiometric and magnetic surveys, by hydrogeochemical surveys, surface and subsurface geologic studies, and the application of improved geochemical exploration and resource assessment methods (Table 1). In brief review, the current status of each of the five basic NURE elements is as follows: In the Aerial Surveys, in the conterminous 48 states, the flying has been completed in 89 of the NTMS 10 x 2° NURE quadrangles, and is in progress in 39 more (Figure 1). Complete quadrangle data have already been open filed for 46 additional quadrangles, for a total of 174 for which data gathering is either complete or in progress. In Alaska, the flying is complete in 42 quadrangles, and quadrangle data have been open filed for 34 more, for a total of 76 (Figure 2).

Jan 1, 1979

By R. C. Kellner

Duval Sierrita Corporation, a wholly-owned subsidiary of Duval Corporation, operates an 86,000 STPD copper-molybdenum concentrator near Tucson, Arizona. Shortly after production commenced in February, 1970, it became apparent that the reduction crushing system represented a limitation to reaching the design capacity of 72,000 STPD. The development work performed on the reduction crushers in order to first meet design capacity, and to subsequently increase production to 86,000 STPD is described in this paper. The Sierrita plant is a conventional three stage crushing sys- tem. All crushers were supplied by the Allis-Chalmers Corporation and consist of two 58 x 89 Superior gyratories, four 138b EHD hydrocones, and ten 384 hydrocones. Screening is performed prior to and subsequent to secondary crushing and in closed circuit with the tertiary crushers. Typical throughput rates and equipment sizes are presented in Figure No. 1.

Jan 1, 1975

By G. K. Wilson

This paper will discuss some of the more important aspects to be considered when selecting pumps for mill discharge, cyclone feed or other severe-duty applications Included will be the selection of the pump based on such factors as particle size, particle distribution, head, flow, temperature and pH Other specifics to be covered: The relationship of impeller speed, head and wear factors as they affect pump performance and wear life; the importance of selecting a pump whose performance curve best suits the application; and how the addition of service factors applied to the actual operating conditions can lead to severe operational problems such as premature wear, pump running out on curve, and exceeding horse power limitations.

Jan 1, 1996

By C. O. Lee

The Grand Isle Sulphur Mine is located in the Gulf of Mexico, approximately seven miles off the coast of Grand Isle, Jefferson Parish, Louisiana. The depth of water at this location is about 50 feet. The deposit is on acreage covered by oil, gas, and mineral leases which were originally issued in favor of Humble Oil & Refining Company by the State of Louisiana, and which were continued, maintained, and redesignated by the Department of the Interior of the United States, pursuant to Section 6(b) of the Outer Continental Shelf Lands Act. On September 19, 1956, Freeport Sulphur Company acquired from Humble Oil & Refining Company the sulphur rights underlying the tracts. This assignment was approved by the Secretary of the Interior on July 12, 1957. The Director, United States Geological Survey, approved Freeport Sulphur Company as Operator on July 31, 1957. Actual design began in September 1956; the first structural contract was let December 15, 1957, and offshore erection began in June 1958. The initial phase of construction will be completed and production started in early 1960. The estimated total cost of the project is $30,- 000,000, of which $8,000,000 is the extra cost for being in the Gulf of Mexico.

Jan 1, 1959

By Ali Ekrem Aritan

Exposure to hand-arm vibration (HAV) among the labor force in the mining industry can result in permanent vibration diseases such as behavioral disorders, visual impairment, osteoporosis, pain (mostly in the hands, wrists, and shoulders), circulatory system disorders, and malnutrition. In this study, the vibration exposure of excavator operators working regularly in 25 different natural stone quarries was measured. In addition, the relationship between vibration exposure and rock properties was investigated. Gloved and ungloved vibration measurements were performed and revealed that antivibration gloves reduce excavator operators’ vibration exposure by 7.10–25.95%. Samples from each quarry were characterized with rock mechanics tests. The correlations between the hand-arm vibration measurements and the natural stone physical–mechanical properties (uniaxial compressive strength, Shore hardness, Knoop hardness, apparent density and total porosity) were determined to be over 70%. One finding of the study was that the health risk in excavators cannot be reduced sufficiently by the sole use of antivibration gloves. Furthermore, the excavation of any rock with a Knoop hardness above 121 is associated with an 81% risk of HAV. To increase awareness of the danger of vibration exposure for natural stone miners, training programs should be provided, and technical and operational changes should be implemented.