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By P. Share

As part of JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), high-resolution tiltmeters were installed during 2007 at Mponeng gold mine, South Africa, in an attempt to study and understand the risks posed by in-mine seismic events and to subsequently use the knowledge gained to mitigate these risks. In December 2007, an M2.2 event occurred at Mponeng and was detected by the tiltmeters installed. The tilt expected for the M2.2 event is modelled through the use of numerical and analytical tools and utilizing, as input parameters, characteristics of the event such as the rupture area, the amount of slip, elastic properties of the rock, the state of stress before the event occurred, and frictional parameters of the rupture. The calculated tilt values are correlated and compared with the recorded data, and are found to be of the same order. Certain input parameters, such as the initial rupture point, are further constrained by varying them, during modelling, until the calculated and observed tilt values are approximately equal. From modelling, it can be concluded that the rupture point had to be closer to the location of the tiltmeters. In addition, possible locations acting as source areas for the observed aftertilt are determined. Further modelling still needs to be done to quantify the effects of the tunnel close to the tiltmeters and plastic deformation of the rock mass. Keywords high-resolution tilt data, Mponeng gold mine, M 2.2 seismic event, analytical modeling, numerical modeling, rupture plane.

Oct 1, 2013

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

DESCRIPTION OF OREThe ore consists, in general, of a very finely grained mixture of sphalerite, galena, and pyrite, with a gangue of quartz and schistose material, and contains about one ounce of silver to the unit of lead.Minor minerals are chalcopyrite, tetrahedrite, and ruby silver. The amount of gangue within the ore-bodies themselves is usually less than 20% of the weight of the whole. The ore is banded in a way that corresponds to the structure of the original schists, and is by no means uniform in composition-at one point, for example, blende may predominate, and a few feet farther on the body may become highly pyritic.Owing to the intimate association of the mineral constituents of the ore, it is very difficult to separate them from one another.Although this remark applies to ore from all parts of the field, the difficulty is particularly noticeable with Rosebery ore, the minerals of which are more intimately mixed, and are of smaller grain size than are the minerals of the Hercules ore.To effect a reasonably clean separation, it is necessary to grind the ore so that 90% passes a 200-mesh I.M.M. screen. Microscopic examination of the crushed product shows that 85% of the minus 200-mesh material is less than 30 microns in diameter, or, in terms of screen sizing, is minus 400 mesh. Particles under 30 microns are found to consist, of one mineral only, but in particles over this size separation has not always been effected. For instance, it is known that part of the galena and of the pyrite in the zinc concentrate is associated with sphalerite, and that part of the galena in the mill residue is associated with pyrite. There is only slight association between the minerals in the lead concentrate.

Jan 1, 1927

By M. A. Greenwood

The total value of coal, FOB mine, consumed in the United States was $21 billion in 1985. Roughly $6 billion was spent to transport coal from the mine to the consumer by rail. This indicates the impact railroad transportation has on the competitiveness of U.S. coal as an energy resource. Actually, this is just the tip of the iceberg. When you consider the largest U.S. reserve of coal, the Powder River Basin, which is possibly the lowest cost coal in the U.S., or maybe even the world, the transportation cost is the overriding factor in developing competitive pricing. Rail transportation costs from Powder River can be multiples of 2, 3, or even 4 times the cost of coal FOB mine. About sixty percent of all U.S. coal is shipped by rail. In the case of Powder River Basin coal and many other reserves there are no current alternatives to rail. Are there feasible alternatives to rail transport?

Jan 1, 1986

By Paul W. Johnson, Ralph C. Kirby, Frank A. Peters

An evaluation is presented for a process designed , on the basis of published work , to extract alumina as potassium alum from clay using sulfuric acid and potassium sulfate . The silica residue is separated by filtration . Ferric iron is reduced to ferrous iron , and the alum is crystallized from the solution , leaving the ferrous iron in solution . The alum crystals are separated from the solution and redissolved for feed to autoclave decomposition . In an autoclave the alum is partly decomposed to a basic alum , recovering five - ninths of the sulfuric acid and two - thirds of the potassium sulfate without using an acid plant . The basic alum is decomposed by calcining , and the potassium sulfate is then removed by washing with water . Operating costs for a plant producing 1,000 tons of alumina a day are estimated at $ 96.15 per ton of alumina . The fixed capital cost is estimated at $ 155 million . This process is not competitive under current economic conditions with the production of alumina from bauxite by the Bayer process . Improvement in leaching , basic alum decomposition , and washing could reduce the costs and improve the product which contains some potassium .

Jan 1, 1963

By David Siskind

The authors studied small seismic exploration blasts for vibration characteristics and effects on structures in Mexico. Obtained were 267 three-component recordings of ground vibrations and structure responses from 62 test blasts at six single-story masonry structures. Charges were 4.55 kg (10 lb) of Vibrogel expolsive at depths of 20 and 30 meters. Initial blasts were 240 meters distant and proceeded towards the structures to as close as 5 meters. All blasts were in soil media in two basic types of terrain, low saturated areas and upland dry areas. Structural inspections were before, during, and after the test blasts.

Jan 1, 2002

By William H. Tavenner

1. The 1952 Annual Report of the West Virginia Department of Mines lists nine beds that arc being mined in Logan County, of which the Cedar Grove and Chilton are the most important. The Cedar Grove group, No. 2 Gas, and Alma beds have the largest remaining reserves, in the order given. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 5,411 million tons as of January 1, 1954. Of this total, 3,939 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics were too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimate reserves.

Jan 1, 1956

By H. Thomas, I. N. M. Nday

"*Paper written on project work carried out in partial fulfilment of BSc.Eng (Mining Engineering) degreeThe optimization of the cycle time to increase productivity at Ruashi Mining was an on-site project investigation conducted from December 2017 to January 2018. The main objective of the investigation was to determine the actual cycle time components. These comprise the queuing time, loading time, hauling time, and dumping time of ADTs (articulated dump trucks). Data was also collected on two hydraulic shovels to identify where these could be optimized. The actual cycle time obtained was compared to the theoretical cycle time to ascertain the constraints, which affect productivity. By applying Systems Thinking to the cycle time, man-made constraints of the actual cycle time were identified and recommendations to mitigate them suggested to optimize the cycle time. However, rainfall is a natural constraint that adversely affects the actual cycle time, and which cannot be mitigated.In addition, both the theoretical and actual cycle time were analysed, as well as the theoretical and actual productivity for the year 2017. Based on the findings, conclusions and recommendations were made to optimize the cycle time. IntroductionThe aim of the project was to increase Ruashi Mining’s productivity by 39%, from about 7.537 Mt of broken material mined to 12..367 Mt targeted in 2017.BackgroundRuashi Mining is a copper (main commodity), cobalt (by-product), and acid producer located in the Democratic Republic of Congo (DRC), 10 km from the city of Lubumbashi. Figure 1 shows the location of the Ruashi Mining open pit.Ruashi Mining started production in 1911 and in 2005 the mine was registered as a DRC company owned by Metorex Group Limited. In November 2013, the Chinese company Jinchua Group International Resources Co. Ltd. bought a majority stake in the business. Ruashi Mining currently produces 38 000 t of copper and 4400 t of cobalt per annum. The company has contracted NB Mining (a contract mining company) to transport its ore. To optimize the productivity of the mine, considering ore flow delivery at Ruashi Mining, the cycle time is the indicator used in this project. The cycle time components were recorded on site using a stopwatch."

Jul 1, 2019

By Qing Wang, H. Sevim

Belt network simulators are the most widely used models in the design of belt networks. The simulators developed in the past two decades are reviewed and their limitations are discussed. To overcome these limitations and to provide a design model that can be used efficiently in real-life applications, a comprehensive non-simulation model has been developed. The features of this model are briefly discussed. A real example is used to demonstrate the model's superiority over belt simulators

Sep 1, 1991

By Andrew G. Martin

In 1991, Modular Mining Systems began marketing a Slope Monitoring System (SMS) now installed at twelve mines. The SMS uses automated wire line extensometers to monitor field conditions frequently. Every few minutes, the slope displacement values and current temperature are transmitted to a central computer via a packet radio telemetry system. The desktop workstation receiving the data continuously provides updated displays of active slope monitors and generates audible and visual alarms if movement exceeds user specified thresholds. The computer system also generates numerous graphs and reports for quick analysis of slope stability. This work describes the functionality of the SMS, details improvements to the SMS hardware and software developed for several clients, outlines different installation techniques needed for wall rock and spoil monitoring, and interprets slope movement data using illustrations of stable and unstable conditions.

Jan 1, 1996

By Walter D. Holland

This is one of a series of instruction guides developed to help instructors present health and safety training courses to workers in the coal mining industry. This course is intended for training those, usually the safety officers, who perform surveys fur inhalation contaminants in above ground work areas. The handbook entitled ?Handbook for Surveys of Inhalation Contaminants in Above Ground Coal Mining and Processing Work Areas? (NTIS #PB-243-35";) is used as a manual for the course and as a prime reference when performing the actual surveys or interpreting the sampling results. There are six experiments for the students to perform during the course to familiarize them with the sampling devices routinely used during the surveys.

Jan 1, 1976

By John Meuth, Brandon Fryman, P. E. Hoffman, Joshua Ph. D., P. E. Calnan, Josh Ph. D.

Quantitative Risk Assessment (QRA) can be specifically tailored for use by the commercial explosives industry to calculate risk to employees and the public from commercial explosives facilities and operations. This methodology has several advantages over the American Table of Distances (ATD) which is solely a Quantity Distance (Q/D) analysis. While the ATD has remained essentially the same for 100 years, the safety of commercial explosives in storage has increased immensely. However, the concepts behind QRA calculations are not as intuitive and even at the end of the calculations the values of risk must be compared to something. A few regimes for assessing an acceptable level of risk are discussed in this paper. Risk levels for various United States Federal entities and international agencies are highlighted and suggestions for acceptable risk criteria for individuals and groups are provided. Referencing risk levels from normal daily activities is also done in this paper to make relative the accepted risk criteria. This paper presents some relevant individual risks for everyday activities and some scenarios for group risk for comparison. Individual risk is a straightforward concept however group risk is more complicated. This paper aims to clarify these concepts and provide means to communicate them to the public.

Jan 1, 2019

By Dipankar Gorain, A K. Vishwakarma, Vivek K. Himanshu, Murari P. Roy, Shubham Singh, R S. Yadav

The industrial establishments of a power plant consist of many important structures viz. cooling tower, wagon tippler, track hopper, plants and offices. The leveled foundation is the utmost need for erecting these structures. The leveling of the foundation is done by rock excavation, when the establishments have to be setup in hilly/rocky areas. Drilling and blasting is the cheapest and most dominant method of rock excavation. However, this method has associated hazards in terms of blast induced ground vibration, air overpressure, flyrocks etc. The foundation work and erection of the industrial buildings are done in parallel to achieve the faster construction of the establishment. The challenges to reduce the induced hazards in such cases are more. This paper presents a case study on the controlled blasting method devised for the rock excavation for construction of 2 × 660 MW Obra-C thermal power plant. The foundation work for this power plant was made by excavation of Dolomitic rock. The excavation work was performed in the proximity of the existing residence of the local people and Obra market. With the advancement of project, the excavation was also performed in the proximity to the ongoing construction work of various industrial buildings. Accordingly, the controlled blasting pattern was devised suitable to the specific sites. The pattern consisted of variations in blasthole diameter, burden-spacing, maximum explosive charge per delay, total explosive in a blasting round, initiation system and direction of initiation. The suitable muffling arrangements were also used, when the blast was conducted in the close proximity to the structures. The initial blasting pattern was established by analysis of blast vibration wave propagation characteristics. Thereafter, the final pattern was adopted for the safe excavation at the site. The safe excavation for the foundation work of this power plant has been completed successfully based on the devised controlled blasting pattern.

Feb 6, 2023

From 1999 to 2008 rock related accidents accounted for 75 fatalities, nearly 6,000 injuries and almost 14,000 incidents (Pappas and Mark, 2011). Clearly this shows that rock related safety on coal mines remains a serious issue and more effort is needed to address this hazard. This paper reviews support design considerations and monitoring needed to improve rock related safety in room and pillar coal mines in the USA. From the present study design considerations continue to evolve and improvements in technology and a better understanding of failure mechanisms and methods to prevent these failures from occurring are in place. At first glance, the design of safe and efficient underground openings appears simple until the designer begins to realize the complexities and variability of geometries, geology, loading and stress influences, support designs and other factors such as corrosion and economics. Ultimately the goal of all designs is to ensure that it can be completed safely, last for the duration of the design life and it is economically feasible.

Aug 1, 2013

By Perry N. Halstead

This report describes two goniometers that, by simple manipulation, can be used to ascertain the attitude of a joint, vein, or fracture plane observed on the planar projection of a borehole photograph taken with an NX borehole camera of the type developed by the U.S. Army Corps of Engineers. One goniometer was designed to interpret photographs taken in vertical drill holes and the other for photographs taken in inclined drill holes. In practice, several measurements are made on each photograph with the goniometer. These data are then substituted into mathematical equations, which are derived in this report and the attitudes of fracture planes are determined.

Jan 1, 1968

By J. R. Thoenen

Profits in the crushed-stone industry, as in any other, represent the difference between selling price and production cost. When consumer demand increases rapidly, as occurred in the crushed-stone industry from 1918 to 1927, selling prices tend to rise. Cost of production usually rises, also, owing to the expense of expanding facilities, searching for and developing new quarries, and purchasing, installing, and operating new equipment. Frequently, also, the inattention of managements to the details of operating costs is responsible for their increase. This is not due to negligence but rather to the necessity of confining attention to the problems involved in producing material to supply orders. When market conditions change and consumer demand becomes stabilized or contracts, the producer's attention usually is directed to assuring the orders necessary to keep his enlarged facilities busy. Hence, competition increases and soiling prices decline.

Jan 1, 1939

By Jane Spooner

"The papers presented in this edition of the Bulletin cover some of the business issues that face mining companies exploring or operating in jurisdictions outside Canada. While technical innovations may, generally, be seen as fast-moving and farreaching, these papers also show that changes in approach and thinking continue to be evaluated and implemented.The Forum paper co-authored by Roger Taplin of McCarthy Tétrault LLP and Marchand Snyman of Muratie Investments Pty Ltd. highlights the quite radical changes that have taken place in South Africa’s mining industry with the introduction of the Mineral and Petroleum Resources Development Act, 2002, in October of that year, together with the Broad-based Socio-Economic Empowerment Charter for the South African Mining Industry and the Mineral and Petroleum Royalty Bill of March 2003."

Jan 1, 2004

By Thierry Bernard, Guy Gagnon

Blasting at very close proximity to urban areas is typically a situation where both local communities and mining stakeholders get nervous. The context becomes logically even more tensed when the blasting operations have to be performed above an old underground mine. When mitigating subsidence risks requires firing the largest possible shots, the nuisance control (flyrock, vibration, and noise) required by local and national regulations, contrarily urge for being more conservative.

Jan 1, 2014

By S. Jeon, N. Hiroyoshi, N. Kitajima, S. Tanaka, M. Ito, R. Pongsumrankul, C. B. Tabelin

"Gold (Au) extraction is inefficient when crushed waste mobile phones (WMPs) are directly leached by ammonium thiosulfate likely because of the cementation/precipitation of dissolved Au in the presence of base metals like copper (Cu), iron (Fe) and/or aluminum (Al). This study applied physical separation techniques to remove base metals as well as plastics and concentrate the Au containing fractions from WMPs prior to leaching. Coarse fraction of crushed WMP (+2-5.6 mm) was pretreated by jig and magnetic separation to remove plastics and base metals like Fe, Cu, and Al, while the fine fraction (-2 mm) was pretreated by flotation, and float and sink separation. The leaching results showed that Au extraction increased in both of the size fractions. In the coarse fraction, Au extraction increased by as much as 2-fold after pretreated (from 4 to 7%). Improvement of Au extraction in the fine fractions after pretreatments were even more dramatic. Au extraction increased from 4 to 61%. These results indicate that physical pretreatment to remove co-existing common metals and plastics is effective to improve Au extraction from WMPs. INTRODUCTION Global sales of mobile phones are expected to increase steadily in the foreseeable future because a lot of people buy newer phones with upgraded and more advanced functions almost every two years, which leads to the higher generation of waste mobile phones (WMPs). WMPs contain a wide variety of materials including plastics, glasses, base metals and precious metals such as gold (Au). Among all the valuable materials in WMPs, Au accounts for over 80% of its total metal price (Park et al., 2017), so recovery of Au from WMPs is needed."

Jan 1, 2018

By M. Baumann

Operating and maintaining the heavy equipment used in open-pit mining operations is an ongoing challenge for mines. Typical operations employ a combination of shovels, wheel loaders, and haul trucks to excavate and transport the material for further processing. As this is the first point of contact for the material after blasting, it is often a bottleneck of all downstream processes, thus, equipment uptime and efficiency is crucial. Automated systems for bucket tooth monitoring, payload measurement, proximity detection, and rock fragmentation analysis will be examined. The impact of these systems on operation safety, efficiency, and reliability, in real-world scenarios will be investigated. The process of managing all the above fleet of equipment in a mine can be streamlined by connecting the equipment monitoring systems to a central server. Using the central server, the distribution of this information can be automated to ensure that the right people see the data in a timely manner, improving both proactive and reactive responses to threats to safety and productivity.

Feb 23, 2014