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Joseph LeConte, Berkeley, Gal.: I have read with some care and with extreme interest the work of Dr. Don, and have 110 hesitancy in expressing my high estimate of its value. We have here an example of laborious work undertaken in the true scientific spirit and by right methods. Loose statements and rash conjectures are here brought to the test of chemical analyses. By such work only may we hope to reach reliable conclusions and finally to solve the complex problems presented by the occurrence of ore-deposits. Such work as this is not only scientific but Is in the highest degree practical; for while a crude and imperfect science, by interfering with the results of approved empirical methods, may be positively hurtful, a more perfect science must eventually become the only sure guide to practice. Such a more perfeet science can only be reached by such work as Dr. Don's. I am sure every member of the Institute will unite with me in the hope that Dr. Don will continue his work, and that his example will incite others to similar work. S. F. Emmons, Washington, D. C.: I desire to bear my humble testimony to the great value of Dr. Don's paper to the science of ore-deposits, the thoroughness and accuracy of his work, and the immense amount of care-taking and tedious labor which it represents. The only regret with regard to it is that it could not have been published in full. No more important paper in its line has ever appeared in the Transactions. Indeed,

Jan 1, 1898

Prof. Henry S. Jacoby, Cornell University,Ithaca, N.Y. (communication to the Secretary): When a simple beam supports any given load, the lower fibers me in tension while the upper fibers are in compression, and if its cross-section is rectangular the neutral surface, where the stresses pass through zero from tension to compression, is at mid-depth, provided the elastic limit is not exceeded. In addition to the longitudinal stresses, there are horizontal shearing-stresses between the fibers which have their maximum value in the neutral surface, and which equal zero at the upper and lower surfaces, while there are also vertical shearing-stresses. Let another beam of the same dimensions be placed on top of this one, and the load be doubled, it then produces stresses in each beam of the same character, magnitude and distribution as in the preceding case, provided there be no friction between the adjacent surfaces of the beams. Next let these two beams be so firmly united that there will be no motion between them when the same load is again applied. All the fibers in the upper beam are now in compression, and those in the lower beam in tension, while the maximum stresses in the outer fibers are only one-half as large as before. The strength of the combined beams is therefore doubled. If, however, some motion occurs between the beams, then the stresses in some of the lower fibers of the upper beam pass from compression to tension, and those in some of the upper fibers of the lower beam from tension to compression, while the stresses in the outer fibers have a magnitude between the two values previously stated. These fundamental facts relating to the flexure of beams indicate the necessity of carefully designing the keys or brace-

Jan 1, 1898

By Edward Keller

Jan 1, 1906

By Alfred H. Brooks

The developments of the past five years have shown that Alaska, as a field for mining, stands in the first rank among the possessions of the United States. Its annual gold output is now about $8,000,000. It produces silver, copper and coal in commercial quantities and its recently discovered tin and petroleum promise to become important products. Concurrent with the gradual development of this wealth, the mining public has ceased to regard the territory simply as an arctic province where a few placer-miners struggle with adverse conditions to secure a grub-stake or a modest fortune. Of late years there has been a large influx of capital to investigate its mineral resources, but in its area of nearly 600,000 sq. miles there still remain large, unexploited and little-known fields. This work of investigation has been carried on under adverse conditions, and reflects credit on all who have shared in it, whether prospectors, mining engineers, or geologists. It is the purpose of this paper to outline briefly what has been, and is being, accomplished toward furthering the knowledge of Alaska's mineral wealth, and in this connection to present a brief history of the operations of the United States Geological Survey in the territory. A list of the publications of the Geological Survey, which pertain to Alaska, is presented as an appendix, in the hope that it may prove useful to those who are interested in the mining of this northern province. During the Russian occupation of Alaska, from 1783 to 1866, but little attempt was made to delineate its geographic features or to study its geology and mineral resources. The Russian-American Co., which long held control of the territory, was entirely absorbed in the exploitation of its fur trade,

Jan 1, 1905

By G. Hausen, H. Micka

"Modern signal and power electronics made adjustable-speed AC drives technically feasible and reliable and economically attractive. Cycloconverters are discussed as a proven technology for mine hoists. \IntroductionUntil rather recent technical and commercial advances in power and signal electronics, DC motors were used almost exclusively for applications requiring continuously adjustable operating speeds and torques. More recently, the significantly higher efficiency and the accordingly lower operating costs of AC motors gained importance. An effective and efficient speed control of AC motors requires the control of AC voltage and frequency. Table 1 shows typical applications of adjustable-speed AC drives.CycloconvertersOf particular interest to the mining industry are cycloconverters for hoist drives. The cycloconverter represents by far the simplest, most efficient and most economical means of converting a constant-voltage, constant-frequency supply into an adjustable-voltage, adjustable-frequency supply as required for the speed control of AC drives operating in the frequency range to half of the utility frequency.Cycloconverters feeding synchronous motors or induction motors are ideally suited for slow-speed direct-coupled drives."

Jan 1, 1988

By P J. Jacobs

FORACO is the third-largest global drilling services company, and recently celebrated its 50th anniversary. The company’s historical roots are in French-speaking West Africa, delivering hydrogeological drilling services to resource companies, villages and regional centres. Today, FORACO operates over 300 drill rigs in more than 20 countries.The Asia Pacific region of FORACO runs a fleet of 37 late model drilling rigs servicing the diamond drilling, reverse circulation, coal, coal seam gas and hydro drilling sectors.FORACO Australia has extensive experience delivering large diameter coring (LDC) samples to the resource community. In the past three years, the company has been involved in six 8? coring projects in a variety of geographies and geologies, including iron ore, coal and uranium. FORACO has developed proprietary equipment and techniques to deliver cost-effective LDC samples with outstanding core recovery.The FORACO LDC sampling system is hands free, with mechanised rod and corebarrel handing to minimise the risk of manual handling injuries. Sample volumes are six times PQ (the common industry standard for large core samples), with core recoveries consistently above 96 per cent in extremely difficult formations.Eight inch coring is a conventional coring system suited to hole depths up to 150 m. For deeper applications, FORACO has recently invested over $4 M in a 6? wireline coring system capable of achieving depths of 300 m.CITATION:Jacobs, P J, 2014. Large diameter core sampling, in Proceedings Sampling 2014 , pp 71–76 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Chris Normand, Paul Volpe, Eric Wey, Howard Perko, Burt Ogilvie, Patrick Murray

"A refinery expansion project for Marathon Petroleum Company in Southern Louisiana required existing medium to large pipe racks to be expanded for additional capacity. Foundation modifications were necessary in order to add levels to the existing pipe racks. New piles were added and existing pile cap foundations were expanded. Several different pile types were considered. Custom designed large diameter helical piles were chosen, because they can be installed quickly with low overhead restrictions, produce minimal soil spoils, and are cost effective. The load capacity required for piles was higher than typical, off-the-shelf helical piles. In particular, the lateral load capacity demand was high due to wind loads of a hurricane prone region. Methods used to design and size helical piles are summarized including capacity to torque ratio estimation for composite helical piles. Pile load testing was performed in order to confirm design capacities of the helical piles under axial and lateral loading. Measured axial and lateral deflections compared well with predicted values. This case history evaluates the effectiveness of modern helical pile design methods within the context of a real and practical example.INTRODUCTIONAs the capacity of modern installation equipment increases, large-diameter helical piles are being used to support higher loads in more diverse applications. Currently, large-diameter high-capacity helical piles are used for electrical power transmission, power generation, high-rise buildings, bridges, and industrial applications. This case study regards a 2.5-mile pipe rack modification project within an existing refinery. One of the many challenges for engineering and construction of refinery revamp projects is determining how to effectively expand the capacity of existing foundations for additional equipment, piping, and other facilities. Custom designed large-diameter helical piles provided an effective solution to the challenges faced when expanding the capacity of existing pipe racks."

Jan 1, 2017

By A. R. Dover

The Richmond San Rafael Bridge (Figure 1) is a 4.3 mile long major toll bridge span across northern San Francisco Bay. Tutor-Saliba/Koch/Tidewater (TSKT) conducted a comprehensive seismic retrofit, which was at the time Caltrans? largest-ever construction contract at $484 million. The robust foundation retrofit design of 11 bridge piers included the installation of 26 new, large diameter (126 to 162 inch OD, wall thickness 1.5 to 2.25 inches) CIDH and CISS piles, with steel pipe piles installed to tip elevations of Elev. ?140 to -220 ft, in water depths up to 70 feet. The open-ended steel pipe piles had initial sections ranging from 71 to 172 feet long, with full lengths that extended to the bay bottom and then through 100 to 130 feet of marine sediments to top of bedrock. The marine soils of most interest consisted mainly of soft to firm Young Bay Mud (YBM), a silty, moderately-sensitive clay common to SF Bay. A key constructability issue was the prediction of pipe piles ?running? under self weight (198 to 625 kips in air) and pile driving hammer weight (IHC S-500 with total assembly weight of 322 kips). The term "pile running" is used to describe the penetration of the pile into the soil due to the self-weight of the pile only. This issue was critical because 1) there was limited head room under the bridge deck, and 2) if piles run too deep, the pile splicing on several piles would be problematic (the lowest desirable pile top elevation after running was +10 ft). While running measurements are sometimes made during marine/nearshore construction, there is little published data on predicted vs. actual running. This paper discusses the running prediction under self weight for 26 piles, and the methodology used in developing the predictions, which ranged from 15 to 94 ft of penetration below mudline. Pile running was recorded and compared with predicted values. The prediction methodology was quite good, and no significant constructability problems were encountered. The authors ?tweaked? the model to provide a slightly improved prediction method. The paper presents the model, predictions, observations, and discusses important lessons learned.

Jan 1, 2006

By D S. Collins, Z Hosseini, I Pinnock, Y Toya

Microseismic monitoring is regularly used in the mining and geotechnical industries to provide detailed information about rock mass response to operational activities. This paper implements a variable 3D velocity model (VM) at a North American hard rock mine with the aim of further improving the accuracy of seismic event locations. A collapsing method is also used to help analyse two individual seismic event clusters at another North American hard rock mine. In the first case study, the location accuracy of events is shown to improve by moving from a conventional single VM to a variable 3D VM that accounts for voids and different geological domains. The modal average for the event location accuracy improved from 14 m to 5 m when the 3D VM was used. Additionally, the single VM failed to locate 26 per cent of the seismic events that were located by the 3D VM. In the second case study, the distribution of seismic events was further enhanced by using a collapsing method that highlighted planar structures. The collapsing method was performed on two large event sequences that occurred in close proximity and identified different seismic event distributions. One aftershock sequence aligned along a plane, suggesting an activated structure, while the other large event sequence had a more 3D distribution of events, suggesting a complex stress redistribution on smaller structures.CITATION:Pinnock, I, Collins, D S, Toya, Y and Hosseini, Z, 2016. Large event sequence analysis and 3D velocity models for seismic event location accuracy, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 879–884 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J. Carr

Ring gear and pinions used as the final drive on large metallurgical grinding mills are expected to transmit their rated horsepower reliably for long periods of time. Duty is 24 hrs./ day. Life expectancy of such gear sets is of the order of 20 years; that is, each gear and pinion flank is expected to resist failure by pitting for 10 years. This means that for a dual pinion gear set having a ratio of 18.42:1.0 and a mill speed of 10 RPM, every gear tooth will see 105.12 x 106 surface contact stress cycles and every pinion tooth will see 968.15 x 106 surface contact stress cycles in a 10 year period. The allowable surface contact stress on the gear and pinion is determined by the material hardnesses. The rule being the higher the hardness, the higher the allowable surface contact stress may be.

Jan 1, 1985

By Robert M. Vadas

Special considerations are described as they apply to the design of ring gears for high-power grinding mills. AGMA requirements, the importance of the supporting structure, material selection and related field experience are discussed, with special emphasis on available and developing manufacturing technologies.

Jan 1, 1978

By D. N. Madge

A description will be given of an approach to plant process automation based on the strategy of first developing an information system followed by later development of process models. The advantages of this approach over the unit process control will be outlined. Some insight will be given into the risks associated with this method. These risks can be shown to be primarily economic.' Some reference will be made to two Cominco installations in the interests of illustrating the generality of the information systems approach.

Jan 1, 1972

By C. Horstmann, D. Andreo, G. Barthold

"The concept of large single line grinding circuits provides a valid answer in project feasibility studies by reducing capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational aspects, in terms of higher and greater process stability, and reduced operational costs mainly due to the associated lower maintenance expenditures. However, concerns exist in the minerals industry on whether large single line grinding could reduce the overall concentrator plant availability. The mechanical design and integrity, the mill and gearless mill drive integration, as well as assets management aspects of this type of equipment are the key to guarantee successful availability records. Together with an overview of the added value provided by large single line grinding circuits, this paper focuses on risk mitigation strategies during mill and gearless mill drive integration, as well as on the design of the equipment itself, for the key aspects which could put at risk the operations availability.INTRODUCTIONDespite a large long term demand for commodities, the mining industry has never faced complex challenges as it is doing today. Decreasing high-quality and accessible deposits, declining ore grades in existing mines, shortages of electrical energy (e.g. in Chile) and an aging workforce are the most significant among the megatrends affecting our industry. In addition to this, flat underlying commodity prices and high price volatility are currently posing strong requirements to miners when entering into the process of approving investments.Nowadays to get projects financially approved (optimizations, expansions, new plants), capital expenditure has to be reduced, as observed up to 30% compared to the last decade, and at the same time the plant design has to be such to demonstrate that operating costs will also be significantly lower than in the past.When it comes to the concentrator plant, the concept of large single line grinding circuits provides a valid answer in project feasibility studies by significantly reducing the capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational costs, in terms of higher and greater process stability and reduced maintenance expenditures."

Jan 1, 2016

By Robert A. Irvine

Traditionally, cost effective gains in the capacity of material handling systems were a result of increases in equipment size. In general, the use of maximum capacity components in a system optimizes the production "costs per ton." The trend-"Bigger is Better" will continue in material handling equipment. Since it is rare for plant operators to lament an over abundance of screening capacity, one can safely predict that vibrating screens will follow this trend. Large Vibrating Screens - The Challenge Large vibrating screens represent a unique challenge for Manufacturers, Plant Designers, and Plant Operators. The inherent mode of operation for vibrating screens is self-destructive. More often than Manufacturers admit, Designers plan for, or Operators staff for, a vibrating screen succeeds and self-destructs. This is a problem. It can magnify with larger vibrating screens.

Jan 1, 1983

By R. A. Irvine

The use of large vibrating screens presents unique challenges to the screen manufacturer, the plant designer, and the plant operator. The design of vibrating structures that span greater unsupported distances is critical to the reliability of a screen subjected to billions of fatigue cycles. Larger percentages of total plant production become dependent upon fewer, larger vibrating screens. Plant designers and operators must plan for equipment maintenance in a manner which optimizes the production availability of large vibrating screens.

Jan 1, 1985

By P. A. Riveros, R. Molnar, F. J. Baša

"An acidification circuit was installed and operated at the Agnico-Eagle Silver Division refinery in Cobalt, Ontario, for treating ~300 m3 of a concentrated cyanide waste solution with the purpose of recovering its cyanide and metal values. The acidification circuit was designed from parameters determined experimentally at CANMET. Available refinery equipment was assembled according to a flowsheet developed by Agnico-Eagle Mines. The process produced a regenerated cyanide solution containing >15 g/L of free cyanide, which was used for leaching gold ore at another Agnico- Eagle operation. It was estimated that the value of the recovered cyanide offset the treatment cost. BackgroundThe Silver Division of Agnico-Eagle Mines needed an economic and effective method for disposing of ~300 m3 of a concentrated cyanide waste solution that had remained in the plant after the operation was shut down in 1989. As a result of extensive recycling and evaporation, the solution had become practically saturated with metals, cyanide, thiocyanate, sulphate and other components, and was, therefore, an environmental liability for the company. A partial analysis of the solution is presented in Table 1. Initially, the use of cyanide destruction methods was considered by Agnico-Eagle, but the estimates indicated a considerable cost with no credits to be gained. A research project carried out by CANMET showed that a simple procedure consisting of acidification, filtration and reneutralization was the most attractive option, because it enabled the recovery of a substantial portion of the cyanide. Furthermore, the metals would be recovered in the form of a solid precipitate. The research showed that conventional AVR was not applicable because of excessive cyanide degradation and low HCN volatilization obtained with this particular solution (Riveros et al., 1996). This paper describes the procedure used to treat the concentrated cyanide waste solution and the operating practices of the large-scale acidification circuit run at the Agnico-Eagle refinery."

Jan 1, 1998

By Andreas Dietrich

Laser off-gas measurement of CO, O2 and temperature has been carried online in EAFs. A visualization screen shows the values of CO and Oxygen and temperature for the entire heat, and includes the status of furnace equipment. The historical data of the heats are stored such that the furnace performance can be evaluated and optimized. A short comparison between laser based and conventional systems has been carried out related to speed, influence of dust, water, pressure, protection for bag house explosions. A high water and/or dust content in the sample does not represent a problem for this type of system. The measurement method works without interruption even under worst conditions such as dirty scrap, carbon injection etc. The installation was developed in conjunction with Marienhuette, Graz. They are 100% scrap based with a tap to tap time of ca. 46 min. Keywords: Laser Measurement, Off Gas, CO, O2, Temperature

Jan 1, 2003

By E. Baliktsis

We have searched and analyzed several modern technologies aiming at the best applications of environmental management, the studying of quarrying ? mining as well as the excavation sites ? utilization ? rehabilitation. We have used long-range reflectorless laser surveying systems, so as to achieve the fastest and most accurate surveying of the extractive work sites. We also used them, in order to collect field data, measure distances, surveying monitoring stations and environmental parameters ? data. Furthermore these systems can make the field work quite faster, more reliable and credible and have low cost in collecting data even in dangerous and non-approachable areas. We have used and processed on the field data in G.I.S. applications, in order to create 2-D and 3-D digital ground models. These G.I.S. applications present the existing relief and the management of the final stage of the area. The suggested techniques and works needed, for reclamation and utilization of the areas, could be tried, evaluated and well presented. The evolution and utilization of these ?smart? modern tools for the effective environmental management of quarrying ? mining ? extractive activity sites, will be presented by using case histories from the Hellenic territory.

Jan 1, 2002

Track and control the tram maneuvers of continuous mining machines by developing and evaluating a laser sensor system. Background Progressive technology has the potential to greatly improve mine-worker safety, helping to create a safer, better working environment for mine workers by keeping them away from the dangerous face area. To benefit from such technology, the Bureau is investigating remote, computer-assisted operation of mining systems for underground, highwall, and surface mining applications. A cornerstone for computer-assisted operation is an effective guidance system. Since there are no guidance systems on any commercial continuous miners (CM's), the Bureau it-self developed and tested a laser-based sensor system, based on a commercial sensor called Lasernet. The laser-based guidance system employs four laser scanning sensors at fixed locations in a mine entryway to report the angular coordinates of two cylindrical retro-reflective targets mounted on a CM. Using triangulation, a real-time microcomputer system processes the sensor data and updates the xy position and heading (h) of the CM five times per second. Using a simple control algorithm and communications interface to the CM control computer, the system also controls rotational and translational tram maneuvers.

Jan 1, 1992

By Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

"There are a variety of methods suitable to analyse elemental and mineralogical contents of rock drill core samples. Current demands are on fast exploration and objective analysis of ore samples. This paper proposes a combination of Laser-Induced Fluorescence (LIF) and image processing, entitled LIF-imaging, as a potential method for automated mineral analysis of the drill core samples. It is shown that LIF-imaging can produce a mineral map of the fluorescent minerals existing on the surface of the drill core samples. The test cases are drill core samples from a Ni-Cu mine situated in Kevitsa, Finland. The main prerequisite of LIF-imaging technique is a reference data, linking colours to the minerals. This study describes the calibration of LIF-imaging technique using precise but slow Raman spectroscopy. Using regularized logistic regression, a model is obtained that classifies the minerals based on their emitted fluorescent colours in the digital images. The abundance of each mineral group is estimated by pixel counting. The results are compared with X-Ray Diffraction laboratory assays performed on the same samples. The results show that the interpretation of the fluorescent minerals through LIF images corresponds to the XRD results. Furthermore, the utilization of the logistic regression to interpret the existing fluorescent minerals greatly improves the technique."

Jan 1, 2014