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The pyrite-sphalerite-galena and barite orebodies at the Rosebery mine are concordant with the shale host rock and have been deformed into one system of folds with an associated axial plane cleavage. The folds are tight and overturned with east-dipping axial planes. Folds in the sulphide ore are commonly disharmonic, particularly between adjacent bands of different composition.Concentric style folds occur in the competent bands, e.g. pyrite-rich bands. Similar style folds are predominant in the less competent sphalerite-galena-rich bands and also in the shale of the host rock. The trends and plunges of the fold hinge-lines are variable but axial planes are of reasonably constant orientation throughout the mine area. The folds in the orebodies are of limited axial extent, approximating to conical folds, and are arranged in en echelon patterns. The fold system was possibly formed in one period of folding by heterogeneous strain that may have been caused by the presence of a mass of tectonically mobile sulphide ore. Lineations parallel to the ore/host rock contacts appear to reflect movement between the ore and the host rock during folding.

Jan 1, 1972

By Forrest T. Moyer

To keep the mineral and allied industries informed of trends in the causes of accidents and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and publishes, periodically health and safety statistics. This report includes data for 1961 on injury experience, with related employment statistics, at coal mines in the United Status. These data are presented in tabular form under the following headings; General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1963

By C. Marais

The use of machine vision in the monitoring and control of metallurgical plants has become a very attractive option in the last decade, especially since computing power has increased drastically in the last few years. The use of cameras as a non-intrusive measurement mechanism not only holds the promise of uncomplicated sampling but could provide more consistent monitoring, as well as assistance in decision making and operator and metallurgist training. Although the very first applications of machine vision were in the platinum industry, no automated process control has been developed for platinum group metals (PGMs) as yet. One of the reasons is that to date froth features could not be related to key performance indicators, such as froth grade and recovery. A series of laboratory experiments was conducted on a laboratory-scale platinum froth flotation cell in an effort to determine the relationship between the platinum grade and a combined set of image features and process conditions. A fractional factorial design of experiments was conducted, investigating 6 process conditions, namely air flow rate (x1), pulp level (x2), collector dosage (x3), activator dosage (x4), frother dosage (x5) and depressant dosage(x6), each at levels. Videos were recorded and analysed to extract 20 texture features from each image. By using artificial neural networks (ANN), the nonlinear relationship between the image variables and process conditions and the froth flotation grades could be established. Positive results indicate that the addition of image features to process conditions could be used as sufficient input into advanced model based control systems for flotation plants. Keywords Flotation, machine vision, image analysis, neural networks.

Jan 1, 2011

By Dipak Sengupta

This study analyzes the safety, technology, and economic impact of eliminating safety fuse from metal/nonmetal mines, based on operation and manufacturer experience over the past five to ten years. If safety fuse is eliminated, blasting accidents will decrease with no technical impact except for some limited, specific applications. The economic impact will be minor for large operations, but will be significant enough for small operations that some small operations will likely close rather than change. The majority of the mines would probably change over, with the extra cost absorbed by the market. Elimination of safety fuse would have obvious impact on the two manufacturers of safety fuse; one manufacturer already produces an alternative system, and will remain unaffected; the other will be affected if they do not change their production strategy. There will be a very minor effect on the mining industry as a whole due to abolishment of safety fuse from the standpoint of employment or production.

Jan 1, 1980

By Seffen Leppla, Rolf Katzenbach, Matthias Seip

"Abstract The economic and safe design of deep foundation systems in difficult soil conditions is based on a reduction of construction material used, construction time spent, energy consumed and a high-level modelling of the soil-structure-interaction. The special foundation system Combined Pile- Raft Foundation (CPRF), in-situ load tests on the construction site and a sufficient soil investigation allow cost optimised constructions. In any case at challenging projects the observational method has to be applied for verification and quality control of the design. Regarding the 4-Eye-Principle as basis of the quality control management an independent peer review of the planning, design and construction phases is the guarantee for safety, serviceability and optimisation of all projects. Main execution standards for the construction of deep foundations based on the Eurocode 7 are summarised and discussed. The paper presents the basics of the safe and qualified design and construction of foundation systems including quality assurance. The application in engineering practice is shown on achallenging project of high-rise buildings with difficult boundary conditions.IntroductionThe construction of deep foundation elements in inner cities are special challenges due to the limited space for the construction works and the effects on existing buildings (Figure 1).An economic and safe design of deep foundation systems in difficult soil conditions is based on the following main aspects:•,qualified experts for planning, design and construction•,interaction between architects, structural engineers and geotechnical engineers•,adequate soil investigation•,design of deep foundation systems using the Finite-Element-Method (FEM) in combination with•,enhanced in-situ load tests for calibrating the soil parameters used in the numerical simulations•,quality assurance by an independent peer review process (4-eye-principle) combined with theobservational method if necessary"

Jan 1, 2014

By J. E. Hamak

This publication contains analyses and related source data for 920 natural gas samples from 26 States and 2 foreign countries. All samples were obtained and analyzed as part of U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1991

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck, Y. Zheng

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control.

Jan 1, 2017

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck, Y. Zheng

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control.

Jan 1, 2018

By Khamis Y. Haramy

This paper summarizes ground control studies of longwall panel entry systems in two Western U.S. coal mines. Presented are comparisons of in situ pressure change measurements and assessments of chain pillar and entry behavior under a wide range of cover. Results indicate that no one entry system design is universally applicable, and that site-specific factors need to be considered for panel entry design. Relationships between overburden depth, face advance, and magnitude and location of the forward abutment are discussed for western operations. In addition, analysis indicates that use of yield pillars may reduce or eliminate some stress-related problems that plague longwall panel entry design.

Jan 1, 1989

By Dave Rose, David G. Meadows, Mike Westendorf

"Copper Mountain’s concentrator was commissioned in May 2011. The circuit consists of a 34’ x 20’ EGL SAG mill, a Raptor 900 pebble crusher and two 24’ x 39’6” ball mills. Each mill is equipped with a 2 x 8500 HP dual pinion drive system. The plant was designed to process 1585 mtph of SAG feed. From startup, the mill struggled to meet the required production rates. Over time, a major initiative that involved blasting and fragmentation, optimization of the SAG mill in terms of discharge grates, ball size and slurry density, and operation of up to three mobile pre-crushing plants resulted in significant increases in throughput. In parallel, a number of modeling tools, including JK SimMet, were run based on plant benchmarking exercises. Samples collected at the mine site during ramp up confirmed the very competent nature of the ore with drop weight - A*b values of less than 24 being recorded on a variety of plant feeds and lithologies. After due consideration including demonstration of proof of concept, a new pre-crushing circuit incorporating an XL2000 cone crusher and associated screening equipment was designed, constructed and commissioned at the site in August 2014. This paper reviews the history of the original circuit design, the various optimization steps taken and impacts, together with the final pre-crushing circuit and net results.IntroductionThe Copper Mountain Mine is located approximately 20 km south of Princeton, British Columbia, Canada (refer to Figure 1). The region has a long history of copper mining dating back to 1923. The Copper Mountain camp occurs in the 'eastern volcanic belt' of the Nicola Group (Monger, 1989). It is an alkali copper-gold deposit in which the volcanic strata are intruded by early Jurassic dykes, sills, irregular plugs and zoned plutons (Woodsworth et al., 1992). The stratified rocks are relatively fresh with slight metamorphism in the local contact regions."

Jan 1, 2016

THE old mill erected by the .Irvinebank Company consisted of 10 heads of stamps (850 lb.), rock-breaker, Hartz jig, two Krupp tables, two Luhrig vanners, three sand-pumps, one mixer; six flotation vessels, and the necessary settlers. Power was supplied by a small colonial-type boiler, and 10-in. x 15-in Tangye engines. The ore was darted from the mines to the mill and hand-fed, into the rock-breaker, and the broken product elevated into the batter bins and fed into the stamps, the pulp from the stamps passing to a classifier, the spigot to jig, tables, and vanners, the overflow from the classifier passing to settlers. After the removal of bismuth-wolfram concentrates, the pulp was pumped to the molybdenite flotation plant and the olybdenite recovered by flotation.A commencement was made with the erection of the first unit (20 heads) of the new mill in August, 1917, and milling and concentrating commenced in February, 1919.

Jan 1, 1920

By Matthias Pulsfort, Markus Herten, Rolf Breitenbücher, Claudia Fierenkothen

"Secant bored pile walls are frequently used as retaining walls in watertight excavations to cut off ground water aquifers and are subsequently exposed to ground water pressure loading in addition to earth pressure loads. To avoid extra loading from ground water pressure in soils with limited permeability, it can be useful to arrange drainage windows within secant bored pile walls by means of single primary piles filled with porous concrete without reinforcement cages, which usually have to be placed within casings in submerged conditions. This concrete may serve as a horizontal arch between the reinforced secondary piles, but it must however enable vertical draining between load carrying construction beams and the bottom of the excavated pit. In the present submission, the results of several material tests with different mix designs of porous concrete with certain admixtures are presented together with first and important experiences with a wellsuited placement technique for porous concrete casings in small- and large-scale laboratory tests. It can be shown that the usual placement technique of employing a tremie pipe is not suited for this type of unsaturated concrete. Instead, pouring with a particular kind of cone and an open conductor pipe has proven successful.Additionally, special testing methods are currently developed for judging the suitability of the desired concrete mix design in preparation for an upcoming real-scale experimental pile installation in Germany.1. INTRODUCTIONRetaining walls are often built as secant bored pile walls in order to cut off aquifers saturated with groundwater against deep building pits. In soil types with relatively low permeability, however, seepage flow may be permitted, because the quantity of groundwater to be pumped is limited, and the range of influence due to dewatering is not reaching far. Thus, the hydrostatic water pressure on the retaining wall can be considerably reduced, leading to a more economic design (see Fig. 1).In unsaturated soils, the dewatering effect can be achieved by means of porous pervious concrete with a uniform grainsize distribution of aggregates typically placed in a borehole under dry conditions. With regard to the use of porous concrete to be placed at the ground surface in road pavement applications, experience is sufficiently available as shown, for instance, by Neithalath et el. (2010). However placing the porous concrete in a bored pile using a tremie pipe under submerged conditions is a challenge and a completely new approach, because there is a considerable risk of segregation of the fresh concrete, separating the cement lime paste from the aggregates when in contact with water and leaving only neat gravel on the one hand as well as a tight cemented area at the bottom of the pile on the other hand. If this concrete placement is successful, additional dewatering by means of extra wells behind the retaining wall can be avoided. Of course the seepage flow in the adjacent soil needs to be regarded seriously."

Jan 1, 2017

By O. Noirot, H. C. Owens, P. D. Rao, D. E. Walsh, J. R. Mokka

Over a period of seven years (1989-1996) the Mineral Industry Research Laboratory (MIRL) University of Alaska Fairbanks, has investigated the effects of temperature, residence time, and particle size on the degree of low-rank coal (LRC) upgrading for a non-evaporative, hydrothermal drying process, also known as hot water drying (HWD). Three Alaskan LRCs were used in this study: Usibelli coal (Seam No. 4) from the Nenana Coal Field, Little Tonzona coal from near McGrath, and Beluga coal from the Beluga-Yentna field on the west side of Cook Inlet. Replicated, factorial tests were conducted. Experimental results indicate that most of the low-rank coal upgrading via HWD occurs rapidly within the first 10-20 minutes of residence time. Thereafter, the upgrading process slows down and over 100 minutes of additional residence time are required to produce similar percentage increases in coal properties to those achieved in the first 10- 20 minutes. The properties of the hot water dried products were very sensitive to process temperature. Calorific value, carbon and oxygen contents, equilibrium moisture levels and Hardgrove gindabilities all appear to change linearly with temperature within the 275°C to 325°C range.

Feb 24, 1997

By D. M. Aloi

In today's evolving and globalized world, mining companies are being pressured to move beyond compliance towards long-term sustainability and sustainable development. Companies are expected to "engage" with communities and measure the success of these engagements without a clear understanding of "how" to do this. This move, away from "Corporate" Social Responsibility (CSR) and compliance, develops more of a focus on "Community" Social Responsibility and sustainability. This shift in focus leads to the development of world-class projects that provide sustainable development for people, reduces the incidence of costly delays, and promotes good global citizenship for corporations. The process of "engaging" communities in mining project design and development leads to a stronger license to operate and sustainable development. To create this mutually beneficial relationship between communities and companies, communities must be "engaged" in the mining process as early as possible, preferably during the exploration or the concept phases. How to create this "engagement" remains elusive. How to measure the progress of this engagement is also problematic. The quantitative and qualitative metrics needed to measure both positive and negative impacts of the mining and community relationship will be discussed.

Jan 1, 2007

By H. M. Smith

The production of oil during the early development of new oil fields is usually accompanied by large quantities of natural gas. Since in most fields gas under pressure is the main source of the energy causing the oil to move through the sands into the wells and thence to the surface, coincident production of natural gas will continue as long as present-day producing methods are used. Generally the use of this gas is restricted, since markets are not readily available. Consequently, a large portion of the gas produced is often wasted by being blown into the air. The magnitude of gas waste is well brought out in the following statement by Miller:5 Only a few outstanding examples need be cited to show the enormous production of gas that accompanies the discovery of new sources. In April, 1927, the Ventura field produced approximately 210,000,000 cubic feet of gas a day; and during the summer of 1927 Alamitos Heights reached a peak gas production of 102,000,000 cubic feet a day; on December 1, 1928, as a result of the summer's deeper drilling in the Long Beach field, surplus gas production amounted to 125,000,000 cubic feet a day. It is estimated that in January, 1929, the Santa Fe Springs field will have a daily gas production of 387,000,000 cubic feet from the recently discovered Buckbee oil zone. Of this amount 274,000,000 cubic feet a day will be the surplus above the amount required for field and plant fuel, taken out by utility corporations, and that used in repressuring the Meyer sand which lies above the Buckbee zone.

Jan 1, 1931

By AIME AIME

For the convenience of persons who desire to file, or otherwise use separately, the technical papers in Section II of the Bulletin, each of these papers has been paged and wired by itself; the whole collection being held together by a single, heavy wire, upon the removal of which it will fall apart into individual pamphlets, substantially like those formerly issued. A small stock of separate pamphlets, duplicating the technical papers given in Section II of this Bulletin, is reserved for those who desire extra copies of any single paper. All communications concerning the contents of this Bulletin should be addressed to Dr. Joseph Struthers, Assistant Secretary and Editor, 29 W. 39th St., New York City (Telephone number 4600 Bryant).

Jan 1, 1907

By M. Tangstad

Keywords: Pyrometallurgy, ROMA, Norway, furnace, fines The ROMA project is a competence project on optimizing the usage of raw materials and energy in the ferromanganese, silicon, and aluminium industries. One of the items investigated in this project is the effect of fines on the furnace, and the usage of agglomerates versus lumpy ore. From lab-scale experiments it is shown, that for the charge to agglomerate in the furnace, the charge has to be exposed to a temperature higher than about 1200°C, independent of fines content. The fines less than 1 mm also showed higher agglomeration properties, compared to 2?4 mm, which showed no agglomeration property at all. The properties of agglomerates are very dependent on the pre-treatment of the agglomerate. Sinter and pellets, which have been heated to high temperatures, show a better strength, but also a lower CO reactivity. Sinter also shows a lower melting temperature compared to the ore.

Jan 1, 2011

By E Villaescusa, C Drover

Fully resin encapsulated threaded bar and cement grouted cable bolts are common forms of reinforcement for underground mining excavations constructed at great depth. These elements are frequently installed to dissipate the dynamic loads caused by violent rock mass failure mechanisms. Failure of the ground support scheme without rupture of the reinforcement elements implies that the maximum energy dissipation capacity of the scheme was not utilised. The ground support damage mechanisms are useful to identify in this context as they reveal vulnerabilities which limit the scheme performance. This paper presents a number of field observations of reinforcement performance following a range of dynamic loading conditions. It was observed that fully resin encapsulated threaded bars exhibit variable behaviour. In particular, inconsistent resin encapsulation was frequently observed in combination with surface support failure, indicating that the retention function of these elements may allow preferential loading of the surface support system. Observations of cement grouted, twin-strand plain cable bolts reveal a common mode of damage involving differential displacement across the steel-grout interface and slip of the cable within the borehole. This is common where strands are not mutually tensioned with barrel and wedge assemblies. Surface fixtures that exceed the strength capacity of the cable strand are required in order to minimise the occurrence of this response. Improved load transfer from the rock mass and surface support to the cable can thus be achieved, particularly where small block size failure occurs.CITATION:Drover, C and Villaescusa, E, 2016. Field performance of fully encapsulated reinforcement during violent failure events, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 659–668 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By H Kurth

Geoscan is used for multi-elemental analysis of conveyed bulk materials in real time. It has been used for coal analysis since the 1990s, in the cement industry, and since 2003 for measuring mineral ore quality. Geoscan-M has proven performance and demonstrated paybacks of weeks or months, in iron ore, manganese, copper, zinc-lead and phosphate industries. Geoscan-M measures continuously through the full bed depth and is unaffected by belt speed, particle size, layering and dust levels. Increments of two minutes (typically one to five minutes) are accurately measured and provide the plant operators with tonnage weighted results of each element within seconds.A Geoscan installed after crushing is able to measure quality shortly after mining. The analysis results can be used to divert the increments based on composition, such as diverting waste for disposal and diverting marginal material to a stockpile for processing at a later date. The bulk sorting process allows different qualities to be placed into relevant stockpiles for subsequent blending. Material meeting product DSO (Direct Shipping Ore) quality can bypass a beneficiation circuit to prevent unnecessary treatment costs. An analyser in a blending application enables proportioning of different quality feed materials from multiple stockpiles to achieve a desired compositional consistency for process feed. The parameter used for decisions may be; a) primary metal content, e.g. Cu, Fe, P, etc. b) deleterious component content, e.g. Mg as an indicator of talc content, c) process parameter content, or a combination of these. Process parameter content may be the elemental ratio between critical components, e.g. Cu:S ratio, Fe:Si ratio, basicity, Lime Saturation Factor, etc. or the content of an “indicator” element, e.g. Si as an indicator of material hardness or grindability.Measurement of the composition in real time enables prompt feedback to the mining operators and also feed forward to the process operators. Compositional variability can be critical in the process and advance warning enables appropriate reactions prior to processing. This may include modifying the feed rate, changing the feed blend (through additives), or modifying reagent dosing in anticipation of a change in feed quality. Benefits include, but are not limited to; reducing waste processing, improved feed grade stability, reducing energy, water and grinding media consumption, producing less tailings, increasing process efficiency, higher metal recovery, better plant utilisation, reducing plant downtime, better utilising mined material, all achieved using the same process plant throughput capacity.CITATION:Kurth, H, 2015. Optimising plant feed quality and process performance using Geoscan elemental analysis, in Proceedings MetPlant 2015, pp 373–380 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Z. T. Bieniawski, José Miguel Galera, Benjamín Celada

TBM case histories from over 400 tunnel sections are analyzed presenting a comprehensive application of the Rock Mass Excavability (RME) index (Bieniawski et al.2006). The paper introduces two new adjustment factors, called the Factor of Tunnel Length and the Factor of Crew Effectiveness, which were established to represent more realistically the interaction of the rock mass characteristics, the TBM parameters and the performance of the crew operating the machine. A new correlation is provided for predicting the average rate of advance of double-shield TBMs working specifically in the double-shield mode.

Jan 1, 2007