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By A. W. Ruff

The seismic wave produced by an explosive is very important in blasting. A true understanding of the wave is only important when considering possible structural damage to buildings located near the blast, but it is also of primary importance when considering rock fragmentation. Because of the importance of the seismic wave to fragmentation, a finda-mental study of the seismic wave and its effect was made at the Cananea Consolidated Copper Co.'s mine at Cananea, Sonora, Mexico. Strain gages were used to measure the strain in the rock when nearby explosive charges were detonated. The variance in the circuit voltage caused by changes in the resistance of the strain gage was measured with an oscilloscope and recorded with a Polaroid camera. CONFINED DRILLHOLE CHARGES To record the seismic wave from a confined drillhole explosive charge, a gage was cemented to the bottom of a 4-in diam drillhole. The horizontal gage hole and nine horizontal charge holes were drilled perpendicular to the center line of the 2-39 drift and 4 ft above the floor. The gage hole was 29 in. deep, and the charge holes were drilled so that each bottomed 1 in. deeper than the gage hole. The gage was installed with its axis horizontal and parallel to the 2-39 drift. The charge holes had the following horizontal distances from the gage: hole 3, 3 ft; hole 4, 4 ft; hole 5, 5 ft; hole 9, 9 ft; hole 10, 10 ft; hole 14, 14 ft; and hole 15, 15 ft. Figs. 1 and 2 show the relationships of the gage and the charge holes. Charges of 80 pct special gelatin, which weighed 50, 100, and 150 g were exploded in the charge holes and the seismic waves were recorded. All charges were stemmed with 200 g of mud and detonated with an electric blasting cap. Fig. 3 shows the recorded seismic waves. The reflected components of the waves were too weak to be objectional on these records. Table I shows the data taken from the wave forms. The approximate average velocity of a wave with a 9-ft travel distance was 12,900 fps. Since different charge weights were used, it was necessary to scale the data. The scaled maximum compress ion-strain data and the scaled maximum tens ion-strain data are shown in Figs. 4 and 5, respectively. Figs. 6 and 7 show the strain-distance data from Figs. 4 and 5 converted to a 1-lb charge. The results showed that the wave consisted of an initial compression pulse followed by a tension pulse. The amplitude of the tension pulse approached the amplitude of the compression pulse as the distance between the gage and the shot increased. The decay rate of the seismic wave is very important in the evaluation of the blasting characteristics of a rock. When high-amplitude stresses are produced, as in rock fragmentation, the rate of decay is much more rapid than when small amplitude stresses are produced. In underground mine blasting, the burdens are usually not greater than 6 ft and the decay is very rapid. The rapid seismic-wave decay rate in the fragmentation range means that in practice, if the minimum weight of powder is used to break a specified burden, only a very

Jan 1, 1961

By J Kelly, C Kelsey

The Autogenous Kelsey Axial Displacement (KAD) mill is essentially a short retention time centrifugal mill, designed to effectively harness extraordinarily high concentrations of input energy for efficient particle size reduction. The mill which has an operating duty band extending from primary to ultra-fine also has the unique capacity to generate fine and ultra-fine products from single stage size reductions of either coarse or fine mineral feeds, in both wet or dry operating modes. This paper covers developments following a recent optimisation programme which confirmed that mill shell speed and the velocity differential between the shell and the rotating internal disc assembly tips could be optimised in relation to specific energy for a given feed rate and feed size providing the product size remains constant. Subsequent test-work further demonstrated the versatility of the mill with duties ranging from the removal of surface contamination associated with heavy mineral concentrate particles to the production of premium ultra-fine talc, from a single stage of size reduction. Open circuit grinding of a rougher gravity concentrate to liberate gold ahead of leaching also highlighted the scope for the application of low cost KAD milling for a range of hydrometallurgical feed preparation duties, which involve fine and ultra-fine grinding.CITATION:Kelly, J and Kelsey, C, 2013. Advanced media-free fine and ultra-fine grinding - The Kelsey axial displacement mill, in Proceedings MetPlant 2013 , pp 152-161 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Branagan D. F

The geology of the area studied is briefly described, together with the prospecting methods used in the search for copper, lead, zinc and uranium ore bodies.Four prospects, Mt. Corella, Yanasinga, Lawlor's and Greenmount, which were diamond-drilled, are described in detail and geochemical results are discussed in relation to the mineralization found. Copper anomalies were found wherever intrusive rocks were mapped, and showed a much closer relation to geology and mineralization than did the predominantly lead and zinc anomalies.Geochemical prospecting aids in the overall mineral search programme because of its speed and economy, as it helps to pinpoint areas worthy of detailed geological examination. Geochemical anomalies are a guide to favourable zones but may not indicate the presence of ore.INTRODUCTIONDuring 1953-55 the National Lead Company of New York carried out a search for minerals in an area south and west of Cloncurry (Fig. 1) in rocks of Precambrian age. After reconnaissance mapping, a number of prospects were chosen for closer examination by detailed geological mapping and geochemical sampling, and from these prospects, five sites were selected for drilling.This paper records the salient features of the exploration programme and discusses the geology and geochemistry of four of the prospects-Mt. Corella, Yanasinga, Lawlor's and Greenmount. Practically all the prospects examined showed high zinc "anomalies" or "dispersion" trains. Greta, Mt. Corella and Lawlor's prospects showed some copper anomalies and, to a lesser extent, lead anomalies. In particular, Greenmount exhibited striking copper anomalies.

Jan 1, 1960

By Harry: Lobb Verakis

Mining operations have made tremendous strides in improving the safety of blasting as shown by the significant and continual decrease in fatalities and serious injuries. Advances in blasting technology and blasting practices have played a significant role in reducing fatalities and injuries. However, even with the decline of fatalities and injuries blast area security continues to be by far the leading factor in blasting accidents. Even though there continues to be an increase in the use of industrial explosives and blasting agents in the U.S.A., the decline in fatalities and injuries from blasting accidents has persisted.

Jan 1, 2010

By Thomas Hans Kleine

In general the software required by a blast designer includes tools that graphically present blast designs (surface & underground), can analyze a design or predict its result, and can assess blasting results. As computers develop and computer literacy continues to rise the development of and use of such tools will spread.

Jan 1, 1995

Australia is the world's leading producer and exporter of mineral sands. Despite increased production from some other countries in recent years, Australia maintained its No.1 position in 1988 among world producers of mineral sands concentrates. Production of the titanium minerals -- ruffle, ilmenite and leucoxene, as well as synthetic ruffle -- by the seven companies currently comprising the Australian industry increased in 1988 in response to continuing strong demand for feedstock by the pigment industry. Production of co-product zircon remained at the 1987 level, reflecting declining zircon grades. Exports of mineral sands concentrates increased in 1988; export earnings exceeded $300million. Prices for mineral sands concentrates are now at a historical high and, assuming that the world economy remains strong, real prices should continue to trend upwards in the short term. Exploration in the Eneabba-Cooljarloo region and the Scott River area, both in WA, the Murray Basin, Vic, and the central Queensland coast area, has identified substantial resources of heavy mineral sands. These discoveries have reversed the trend of the early 1980s of falling resources of mineral sands. In 1988, BMR estimated that economic demonstrated resources (EDR) of ilmenite, rutile, zircon and monazite combined was about 72.8 million tonnes. However, a substantial portion of the resources on the east coast are frozen as a result of environmental considerations. The proportion of mineral sands concentrates processed in Australia increased with the commissioning of two new synthetic rutile plants; Australia is now the world's leading producer of synthetic rutile (total capacity 272000 tonnes), most of it for export. Australia's two TiO2 pigment producers have both increased capacity, lifting national capacity by some 70p ercent to over 120000 tonnes/yr. As part of the expansion one producer converted from the sulphate to the chloride process. Other new pigment plants are being proposed for the future.

Jan 1, 1989

By C Garlick, O Gregory, H Rogers, B I. Winters, Z C. Ye

BHP New Zealand Steel produces iron from titaniferous ironsand by a direct reduction process comprising multihearth furnaces/rotary kilns/electric iron melters. The electric iron melter is a six-in-line rectangular submerged-arc furnace which takes the partially reduced ironsand (80 per cent metallisation) from the rotary kiln and completes the reduction process to produce iron of nominally three per cent carbon. As the melter operates at around 1500¦C and under very hostile conditions, it is near-impossible to obtain any basic operating parameters such as the velocity and temperature distribution in the slag and in the molten iron. As a first attempt to understand the operating conditions inside the melter, a scaled room-temperature model using wax and water to represent the slag and iron, was constructed. This paper will report on some of the preliminary model results on the temperature distribution.

Jan 1, 1995

By D. L. Cluff

Ventilation Air Methane (VAM) is a high volume low concentration methane source. The capture or use of methane from VAM is challenging, which results in the routine discharge of methane into the atmosphere. Mitigating VAM has the benefits of providing an energy source and reducing the atmospheric Greenhouse Gas (GHG) burden. The GHG radiative forcing effect of methane is 17?23 times as potent as carbon dioxide on a 100-year time horizon. Thus, any reduction in atmospheric methane would be beneficial. The calorific value of methane is 55.5 MJ/Kg; therefore, a 100 m3/s flow with VAM concentrations from 0.1?1% can provide 3.8?38 MW of exploitable power. Strategies to mitigate VAM such as: Thermal Flow Reverse Reactors (TFRR), Catalytic Flow Reverse Reactors (CFRR), Lean Burn and Catalytic Gas Turbines, Biothermica Vamox®, Megtec VOCSIDIZER©, and Vamcat? are briefly reviewed. The review of VAM mitigation technologies reveals disadvantages such as the need to maintain a minimum internal heat capable of oxidizing the methane. This requirement uses all of the available methane up to the point of reaction sustainability and up to half at the highest methane concentration in VAM. Some systems may introduce a pressure drop to the ventilation system, which would impinge on the existing ventilation system design. These impediments necessitate the development of a more amenable technology. In the proposed system, gas turbines (GT), coupled to a combustion chamber with an external fuel supply, assist the combustion of the VAM. The combustion-chamber coupled system provides electricity, while the heat contained in the GT exhaust gases increases the temperature of the VAM, encouraging the development of a flame inside a combustion chamber. The flow from the combustion chamber streams through a primary air/fluid heat exchanger capable of producing steam of a high enough quality to generate electricity using conventional steam turbines. The residual heat after primary extraction, directed through other equipment, provides additional heat based products such as industrial scale dry air, chilling by an absorption chiller or hot water. The overall design of the system is scalable for low to high VAM flows or variations in concentrations and is capable of providing the company or community with heating, chilling, hot water, electricity or motive force as needed by the particular site or community. The Multi-generation system uses heat from three sources to provide clean efficient energy while mitigating the atmospheric emissions of methane. These sources are heat from the GT, often considered waste heat, heat from fuel injected into the igniters and heat from the VAM. The opportunity to collect carbon credits may improve the economics. In order to design a system with this capacity, a detailed analysis of the combustion characteristics of three separate flows is required. VAM is the main airflow, having the highest volumetric effect, while the GT exhaust and the additional fuel added to the hot exhaust flow of the gas turbine are lower flows, but have a higher velocity and temperature. The aim of the modeling undertaken in this work is to establish the combustion dynamics, degree of pre-heating required and the geometry essential to the design of combustion based VAM mitigation multi-generation systems.

Aug 1, 2013

By Xie Qiang

It is known that the stress state inside rock discs under Brazilian tests is neither simple compression nor tension, but a complex combination of both stress types, as well as for a beam subjected to bending, where compressive and tensile stresses are separated by the neutral axis. In this study, AE generation was obtained on pure white marbles from south Portugal that were submitted to both Brazilian and bending tests. Main questions to be answered were: (1) Does Kaiser effect exist in tests which create complex distributions of tension and compression? (2) Are there any meaningful differences in AE behavior of marble under Brazilian and bending tests?

May 1, 2009

By G. C. Smith

Process control applications in the minerals processing industry have grown extensively over the years due to the many benefits derived, both financially and operation-wise. Although control theory is widely known, conventional control does not address many of the problems posed by minerals processing circuits. Some of these problems include interactions between process units, large dead times, few and sometimes unreliable measurements of process variables, non-linear systems, disturbances entering the process, processes with varying dynamics, and many more. For the past 26 years Mintek has been active in the field of providing specific, customized solutions for the minerals processing industry. This paper focuses specifically on applications in milling and flotation control. The underlying control principles have been applied to a wide range of other processes including submerged arc furnaces. Advanced control application is implemented on a common advanced control platform, called the PlantStar. Much innovation has been brought to the fore in terms of adapting theoretical techniques and developing new methods to resolve specific milling and flotation circuit issues by using process control. The general approach adopted by Mintek when implementing advanced control is to enforce stabilization of the process as a solid foundation for optimization strategies to be built upon. In doing this, a robust control solution is presented, and the end result is flow and level stability, better product quality regulation, increase in throughput and a stable feed to downstream processes. The MillStar advanced milling control system ensures that the milling circuit is at all times easy to operate while achieving optimum product quality and throughput. Stabilization should include product size regulation and sump level control. Another important aspect of stabilization control is the handling of milling circuit constraints without introducing cyclical behaviour and with minimal disturbance to the final product quality. Process constraints may include factors such as process water limitations, cyclone feed density, and cyclone underflow angle. An optimization strategy should be developed to increase the mill throughput without affecting product quality or introducing mill overloads. The relationship between solids feed and power draw is examined and manipulated for optimization. The interactive nature of flotation circuits and the presence of recirculating streams tend to make satisfactory control almost impossible with conventional techniques such as PI (Proportional plus Integral) or PID (Proportional, Integral and Derivative) control. The FloatStar Level Stabilizer simultaneously considers all the flotation levels in a circuit by use of a multivariable algorithm, and takes compensating action in anticipation of disturbances. The FloatStar Flow Optimizer is an optimization strategy that controls the concentrate flow rate between various sections of a flotation circuit (e.g. Rougher ?Cleaner; Cleaner ?Recleaner). By controlling the concentrate flow between the sections, the mass pull, circulating loads and residence times of the circuit can be stabilized, thereby enhancing the performance of the flotation process. Optimizing grade and recovery are coupled with the dynamic optimization of circulating flows. The FloatStar Grade-Recovery Optimizer will maximize the grade in a section, whilst ensuring that recovery or any other process specific limits remain within predefined limits. With successful applications on several milling and flotation plants worldwide processing amongst others PGMs, gold, copper and nickel, Mintek has shown that it is a leader in milling and flotation control innovation

Jan 1, 2004

By J. Geisler

When addressing Germany’s resource supplies, we need to distinguish between those domestically available and imported ones. Resource extraction ostensibly competes with the designation of protection areas. However, the parallel existence of wildlife and plant life, and operations in the areas used for resource extractions is continually underestimated. The European Commission has compiled guidance documents facilitating the extraction of resources from protected areas. With regard to resource productivity, the market appears to be the appropriate instrument for minimising resource consumption. Policy makers are now called upon to create a legal framework leading to a consensus accepted by society.

Jan 1, 2011

By A. Kostin

GIS and multivariate geometric distribution have been used to predict the association of high-level intrusives with hydrothermal alteration related to iron oxide Cu-Au (IOCG) mineralizing systems. Several examples in the Russian northeast are presented in this paper. IOCG ore deposits can have enormous geological resources containing significant reserves of base, precious, and strategic metals, and hence are economically attractive targets for mineral exploration. To date, examples of this type of mineralization have not been reported from the northeastern area of Russia. The Tarinskiy ore cluster, located in Eastern Yakutia, shows brecciated altered rocks with sulphide and iron oxide cement, which is typical for IOCG mineralization of the iron oxide Cu-Au±U type. This cluster was formed near surface and is linked with the Rep- Yuruinskiy pluton. It has potential to host new world-class precious metal deposits in northeastern Russia

Jan 1, 2014

This report covers the results of an industrial engineering study that assessed the safety and efficiency of underground ore handling in U.S. metal mines. Significant conclusions that will be of benefit to the entire mining industry are the following: It appears from the study that the productivity of the slushing equipment itself cannot be substantially increased using the existing technology; the unsafe situations associated with slushers can be improved by better anchoring practices, by providing better work station layout that incorporates improved clearances and protected walkways over the ore pocket, by lighting the slusher drift, and by improved operator training; improved technology needs to be applied to the movement of broken ore in the stopes; and slushers will continue to be used in the mining industry in certain spedial and unique situations outlined in the report.

Jan 1, 1974

By C. W. Owings

A few of the more progressive mining companies have taken precautions to safeguard employees or man-trips. Specially constructed men-cars -have been provided with special devices or mechanisms to stop the cars on slopes, if the hoisting cable should break. Cars have been equipped with safety chains to connect and hold them together if a coupling should break. Steel frames covered with heavy wire netting have been placed over cars to reduce injuries to the riders from roof fails on slopes. A safety cable passing from the front car to a point above the cable socket on the slope hoisting cable is used frequently as a precaution in case the socket loosens o the main cable breaks at the socket. Such devices are commendable, but the percentage of man-cars and man-trips protected is relatively small - entirely too small. Man-trips that travel level haulage roads are rarely protected safety devices, and haulage roads are seldom inspected by mine officials to determine the condition of roof and ribs.

Jan 1, 1935

By Michel Bustamante

The occasional substandard performances of continuous flight auger in particular soil conditions have prompted the drilling rig manufacturer to improve the standard CFA in order to reduce its negative effects. A real improvement of interest was the launching of the double rotary CFA system. The promising features of the latter have incited the authors to implement an extensive experimental research on pile constructed using this type of technique but in the specific context of cohesive soils. Short-term static load tests were carried out on a total of 9 test piles of various installation techniques in order to compare the respective performances. The promising features of the double rotary CFA have incited the LCPC & Durmeyer Company to implement an extensive experimental research on this type of pile technique but in the specific context of cohesive soils and more particularly in clayey marls. After load tests completion the research has been completed by an excavation of the double rotary CFA piles. All the collected data concerning the implemented program are reported.

Jan 1, 2002

By A. Karadogan, G. Tuncer, A. Kahriman

Determination of optimal blast parameters have been the priority act for blasters on the field due to financial and technical properties of the operation. Therefore many researchs were done to establish a general formula for many years. These intends could reach some empirical and numerical design frames consisting the rock, geology and explosives properties. Blasting parameters have to be adjusted according to the desired fragmentation rate especially on the mines where particle size distrubition after blasting has a great importance. Therefore the blast designs have to be evaluated considering the particle size distribution after the blasts. The Kuz-Ram model which was modified by Cunningham is one of the tools for estimating the particle size. Although it doesn’t give an accurate result, it can be very succesful on modifying the blasting design parameters by establishing a back correlation between the blasting parameters and the exact particle size distribution results which can be easily achieved by digital image processing system. Within the scope of this study, the particle size distribution after blasting was assessed by Split-Desktop digital image processing system and bench blasting parameters were studied considering the desired particle size distribution at Espey colemanite mine using Kuz-Ram and digital image processing system combination to determine the specific blasting parameters for this site.

Jan 1, 2005

By F. Keith Shelton

"INTRODUCTION Cobalt is an essential metal in the normal industrial ac¬tivity of the United States. Being an important constituent of high-speed steels and other cutting-tool materials, it becomes of critically essential importance during periods of national emergency. 3/ The Presidential order of December 20, 1940, included cobalt among other essential commodities that could be exported only under license. The Executive order 4/ listed cobalt metal, cobalt oxide, and alloys containing more than 5 per¬cent cobalt as being within the licensing requirements.There was no domestic marketed production of, cobalt products from 1931 until 1940 when the Pyrites Co. 5/ produced some cobalt oxide. The major portion of the domestic cobalt requirements has been obtained from Northern Rhodesia, the Belgian Congo, and French Morocco. 6/ The uncertainty of sea transportation from those sources of supply demanded that steps be taken to obtain from domestic raw materials an adequate supply of cobalt for use in the materials required for production of indispensable machined war metal products. In connection with the national policy for attaining self-sufficiency of strategic and critical materials, the Bureau of Mines, Boulder City, Nev., Experiment Station initiated studies to recover cobalt from the low-grade oxidized cobalt deposits in the Goodsprings district, Nevada. Hewett 7/ reported occurrence of cobalt specifically in the Blue Jay, Columbia, Copper Chief, and Highline mines and generally over a widespread area in the district."

Jan 1, 1946

By J. H. East, R. S. Sanford, W. M. Traver, W. S. Wright

"INTRODUCTION This report describes the results obtained from a diamond-drill exploration project performed by the Bureau of Mines on the nickel deposits of the Yakobi Island, Alaska. The Federal Geological Survey 6/ completed a detailed geologic study and mapped the area during the summer of 1940, and a Bureau of Mines examining engineer 7/ made a preliminary examination of the deposits in June 1941, at which time core drilling was suggested as the logical means of determining the extent and grade of the deposits. Equipment and supplies were unloaded on the beach at Yakobi Island on October 21, 1941. The drills were moved to Bohemia Basin, where actual drilling operations wore begun under the direction of a Bureau of Mines engineer 8/ on November 7, 1941. Two core-drill holes were completed on December 7, 1941. Upon the request of the drilling contractor, operations were recessed owing to severe winter conditions. Work on the project was resumed April 27, 1942, under the direction of another Bureau of Mines engineer 9/ and was completed August 15, 1942. During the 1942 season, 13 core-drill holes were completed, and 10 surface pits and a tunnel were sampled. A total of 5, 191 feet of core-drill hole was drilled in 15 holes during the entire project. The results of drilling and sampling form the basis of this report."

Jan 1, 1948

By M. R. Smith, H. Kanli

The impact crusher is a popular device for producing crushed aggregates from non-abrasive rocks such as limestones, offering the advantages of high reduction ratios and relatively low installed costs. To extend the application of a process-flowsheet simulator to the quarrying industry, a mathematical model of an impact crusher was therefore developed using the general crusher models of Andersen and Whiten as a basis

Aug 1, 1995

By Fabio Mielli

In these times of increasing costs and diminished returns, energy consumption is one source of savings that remains relatively untapped in the mining sector. Typically, 15% to 40% of operational costs can be attributed to energy in mining operations. This ?process variable? is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. A mining company able to successfully embrace an energy efficiency program is more often than not a successful mining company. Production optimization programs, relatively common today, provide increased production, increased availability of assets and, in many cases, improved quality. They generally ignore the energy question altogether. Production Energy Optimization combines reductions in energy consumption with production improvements to reduce the cost per unit of production while improving emissions reporting. An energy strategy in mining and mineral processing operations is a critical component of Production Energy Optimization. This strategy must support the financial and operational integrity of the business. Developing a successful energy strategy requires a well structured approach such as following: ??Understanding where energy is being used and why, ??Recommending and implementing energy conservation measures, ??Driving visibility to targets and results, ??Re-evaluating continuously. The objective of this paper is to help you better understand the process, tools and technologies that enable mining organizations today to address energy and sustainability issues more tactically and proactively.

Aug 1, 2013