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By P. B. Kelleher

Most of the piers and other pile-supported marine structures in the New York City Harbor area were constructed prior to the widespread use of currently available pile protective systems. As a result, the support piling of many existing marine structures have experienced deterioration to an extent that their structural sufficiency is impaired long before the useful life of the structures they support is over. This situation presents special and unique problems of how to restore the structural integrity of these piles while at the same time allowing full use of the structures they support. Spearin, Preston & Burrows is a 100 year old New York City-based marine construction firm specializing in waterfront and foundation construction. In recent years it has undertaken and successfully completed several unusual projects in the New York City Harbor area involving the rehabilitation of existing, deteriorated piling underneath major, economically important marine structures. This work was accomplished using techniques that permitted full use of these structures. Several different pile rehabilitation systems were used, each having their own particular application to the deterioration problems of the piles supporting each structure.

Jan 1, 1989

By N. M. Skarbøvig

Safety nets have been used selectively in several South African mines over the years. Recently, however, an increased emphasis on mine safety has seen a resurgence of their utilization underground. This renewed interest has, however, also raised questions about the design and performance of these nets and their practical applications underground; these are the subjects of this paper. Generally, mine safety nets are used to protect personnel from falling rock in temporarily supported development ends, tunnels, ASGs and stopes. These diverse applications each require specific net designs, resulting in a wide product range. As a rule, however, mine safety nets need to carry specified static or dynamic loads with the least possible deformation. Because of the application-specific characteristics of mine safety nets, there is no South African national standard for them. Consequently, neither the SABS, nor the CSIR, performs standard tests on these components. In 2007, therefore, SIMRAC made available their Savuka facility for the testing of mine safety nets; the Savuka drop test became the accepted industry test standard for mine safety nets. From late 2007 to mid 2009, Norsenet, in collaboration with SRK Consulting, the designated operators of the site, conducted approximately 200 tests, which formed the core of Norsenet's database of safety net performance under various loading conditions. The test specimens comprised a wide range of net materials and config¬urations; the materials included: high density polyethylene, polypropylene, polyester, nylon, as well as a blend of polyester and polypropylene used primarily for reinforcement ropes. Net configurations encompassed the following parameters: net type, i.e., knotted nets or sewn nets; net strand type, i.e., braids, twines, or webbing; strand size; mesh size; mesh orientation, i.e., parallel or oblique to the net edge; net edge reinforcement, i.e., knotted, tied, with or without reinforcement ropes; internal reinforcement ropes, i.e., diagonal ropes and/or orthogonal ropes; as well as net attachment options, including loops and chainlinks. From the number of variables listed above, and the limited number of tests available, it can be appreciated that the findings of the test series required careful scrutiny. Nevertheless, principal performance factors clearly emerged: besides the obvious net mesh variables, such as net strand material, strand diameter and mesh size, it was the configuration of the reinforcement ropes and their attachment to the net panel which had the strongest influence on net performance. All the structural elements of a safety net need to work together to transfer the imposed load from the net panel, through the reinforcement ropes, to the net attachment points. In this load transference chain, the weakest link limits the strength of the structure. From this development work, Norsenet has gained valuable expertise to custom-design and manufacture nets to clients' specifications. The examples presented in the paper will also show the experience acquired in the installation of nets underground. Future work will include the establishment of a state-of-the-art net testing facility at Norsenet's factory in Vredenburg.. Keywords Mine safety net, safety net, protective device, mine safety, safety net design, safety net performance, safety net applications.

Jan 1, 2011

By J. F. Barkley

Smoke abatement is a subject of which fuel technology, although absolutely essential, is only a part. Its successful accomplishment starts and ends with human factors that must be given thorough consideration; between this "start" and "end" fuel technology is applied. Smoke abatement usually starts from the desire of some person or persons to be free from uncleanness caused by the stack of someone else and ends with the sincere desire of the operator of the fuel-burning equipment to maintain a clear stack. Although "smoke abatement been discussed for many years, it is only recently that the public has been mindful of such expressions as "air pollution" and "air hygiene." The subject has duel in common with that of supplying pure water but is more complicated. The public desires pure water, expects pure water, is willing to pay for pure water, and expects to continue to pay for it indefinitely; it is a development of civilization. It is doubtless correct to say, however, that people in general do not et realize the detriment of air pollution to their well-being or give the question enough serious consideration. This is illustrated by the fact that in city smoke abatement it is the mass of small householders that sins the most and is the hardest to handle. It is rather difficult to assemble a group of people in a room without the air becoming contaminated with smoke. Smoke abatement will lag with the lack of desire for pure air - probably the biggest human factor involved in its accomplishment.

Jan 1, 1939

By Frederic Masse

With widespread acceptance in the market place, many engineers are choosing ground improvement techniques to provide suitable foundation subgrade at sites that would have traditionally required deep foundations. This paper discusses the Controlled Modulus Columns (CMC) ground improvement technique and some case histories highlighting the use of this technique for retail development sites. CMC are a sustainable and cost-effective ground improvement technology that transmit load from the foundation to a lower bearing stratum through a composite CMC/soil matrix. The CMC installation is also an attractive option from an environmental perspective because it utilizes reverse flight augers, which displace the soil laterally. This installation technique achieves two goals: it densifies the soil around the CMC, which improves load transfer into the element and avoids spoil and its disposal. Through the introduction of two cases histories, we will present the key benefits of the CMC technology. Each case history will clearly illustrate how a CMC solution can reduce the overall cost of a project when compared to a more traditional type of deep foundations. They will also show how the use of CMCs has benefits that relate to the overall sustainability of the project. While CMCs are an attractive financial and sustainable option, they have also demonstrated that the performance of the system is comparable to that of deep pile foundations. Because CMCs are a relatively new technology many potential users are not aware of its benefits. While we discuss the use of CMCs to support buildings in this paper, CMCs also have been used for a variety of other applications including foundations for tanks, mechanically stabilized earth (MSE) walls, and embankments

Jan 1, 2011

By Sanna Mustonen, Seppo Mellanen, Mellanen, Pekka Kantia

In Finland Posiva Oy (Company) is responsible for implementing the final disposal programme for spent nuclear fuel of its owners. Company is preparing for the geological disposal in Olkiluoto crystalline bedrock. Excavation will be executed using drill and blast method. Method unavoidably causes variable excavation damaged zone (EDZ) on tunnel surfaces. The EDZ constitutes a risk for long term safety and therefore good control methodology of the blasting technique is required. The thicker the EDZ, the greater is the likelihood for detrimental transport pathways for ground water to transport radio nuclides, should those be present.

Jan 1, 2016

A recently developed technique for use in collieries is described in which samples of gas of relatively high vitiation value are obtained from points deep within a developing goaf by means of pipes. This technique prevents dilution of small quantities of carbon monoxide by large quantities of fresh ventilation air and eliminates interference from shotfiring gases. By using the technique it should be possible to assign a characteristic ratio of carbon monoxide to oxygen consumed to any district and to predict the onset of heatings.INTRODUCTIONGas analysis has played a vital role in detecting heatings in collieries all over the world. By analysing return air from a district and by calculating the percentage ratio of volume of carbon monoxide found to oxygen consumed (known simply as the "carbon monoxide ratio") it has been found possible, in many cases, to assign a characteristic ratio to a district under consideration. This characteristic ratio serves as an index of the spontan~ous combustion tendency of a goaf area. Any definite and consistent increase in the ratioabove the normal figure· indicates that a heating is developing and hence adequate preparations may be made to deal with the trouble.This ratio technique was developed by Graham (1920-21) who found (Table 1) that the temperature of oxidizing coal was directly related to the ratio obtained from analyses of the effluent gas.Until recently, most attempts to employ a similar technique in collieries working the Greta Seam (N.S.W.) were not successful. From experience gained over the past few...

Jan 1, 1961

Titanium and Zirconium Industries Pty. Ltd. separates rutile and zircon from heavy mineral concentrate recovered from sand dunes on the east coast of North Stradbroke Island, Queensland. Separation plant feed is delivered to Dunwich, on the west coast, by a seven mile aerial ropeway traversing the island. Mining and concentration is effected by two floating dredge-concentrators now operating on the beach 31; miles from the aerial ropeway terminal. Heavy mineral concentrate is transported hydraulically from the dredges to the ropeway through a 6 in. pipeline. Six pumps in series deliver 24 ton/hr of dry solids in a pulp containing 13 per cent solids. For maximum economy the transfer pumping system is controlled deliberately to cause transportation in the zone of incipient settlement of solids, ieat velocities below the limit deposit velocity for the particular pipe diameter, pulp density, and specific gravity of solids. Automatic density control, based on a combination of power consumption and pipeline pressure, eliminates the danger of plugging the line but periodic flushing is necessary to remove gradual accumulation of solids in the bottom of the pipe. After 15 months operation the pipeline was descaled with hydrochloric acid to remove severe blistering with rust nodules, regrowth of which is now prevented by continuous injection of inhibitors. After transporting 100,000 tons of heavy mineral the average wear on the steel portion of the pipeline was 0·01 in. and indications are that wear on the asbestos cement portion is less.DESCRIPTION OF OPERATIONSGeographyTitanium & Zirconium Industries Pty. Ltd. (T.A.Z.I.) operates on North Stradbroke Island, some 30 miles southeast of Brisbane, Queensland. The island is approximately 25 miles long and eight miles wide, and is bounded on the east by the Pacific Ocean and on the west by Moreton Bay (Fig. 1). With the exception of a small outcrop of volcanic 1. Manuscript received at The Institute. 8th May. 1962. This paper was presented at the Annual Conference of The Institute. 5th-11th August. 1962.

Jan 1, 1962

By Bhaskar B. Thapa, Christopher Laughton, Michael P. Bruen

At Fermilab, located in Batavia, Illinois, a 4,000-foot underground complex of tunnels and caverns is being excavated on a decline of six percent, at depths of up to350 ft, below grade. The site geology consists of dolomitic and shale formations overlain by glacial till. Since the start of construction in March 2000, work to date has concentrated on the excavation and support of the Target Hall cavern, which is characterized by a low rock cover and a final lining of shotcrete. Ground vibrations, noise levels, and rock movement were monitored during excavation by drill and blast methods to prevent damage to experimental facilities, impacts on surrounding communities, and to allow evaluation of cavern performance. The cavern design was based on a UDEC numerical analysis that was validated during construction by comparison to encountered conditions and measured cavern movements.

Jan 1, 2001

By H Chen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Mesozoic iron oxide-copper-gold (IOCG) mineralisation in southern Perú and the northern Chile coastal IOCG belt have emerged as two of the major exploration targets in the Central Andes in the last two decades. These Mesozoic Andean IOCG deposits formed in two mineralisation epochs, the Middle-Late Jurassic (170–150 Ma) and Early Cretaceous (130–110 Ma), with the major Cu-rich IOCG deposits located in the Early Cretaceous mineralisation belt. The early studies in some IOCG centres support a magmtic-hydrothermal model for both Cu-rich IOCG deposits and broadly contemporaneous Cu-poor ‘Kiruna-type’ magnetite deposits. However, recent evidence from field, geochronology, fluid inclusions and stable isotopes show that in the major Central Andean deposits (eg Raúl-Condestable, Mina Justa in southern Perú, La Candelaria-Punta del Cobre and Mantoverde in northern Chile), the incursion of evaporite-sourced basinal brines or sea water may be a prerequisite for economic Cu mineralisation. Moreover, the Cu-poor massive magnetite deposits could be interpreted as a product from iron oxide melt, with minimal intervention by non-magmatic fluids. Therefore, they could represent two contrasted deposit types and contain little genetic relationships. The different roles of magmatism during the Mesozoic are responsible for the variable mineralisation in the Central Andes, including IOCG, magnetite and ‘manto-type’ deposits. The ore modelling for both the Middle-Late Jurassic and Early Cretaceous metallogenic epochs in the Central Andes are reconstructed.CITATION:Chen, H, 2015. The Mesozoic iron oxide-copper-gold (IOCG) mineralisation in the Central Andes – a refined IOCG ore-forming model in the Palaeozoic Continental Margin, in Proceedings PACRIM 2015 Congress, pp 251–254 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R. Mier

The metals and minerals mining industry has evolved dramatically from the earliest objects ever made out of native copper circa 9,000 BC to the modern developments we see today. To better appreciate past developments and to get a sense of where the industry is heading, a brief overview of mayor industry highlights over the last 100 years will be presented, followed by a discussion on potential global scenarios and by a review on mayor industry trends.

Feb 27, 2013

By Kadri Dagdelen

Design of the ultimate pit limit to direct long range mine planning has been a celebrated problem in the mining industry, and in mining academia, since 1965. Although many papers have been presented on this topic, even today, there is not a single solution technique which is widely accepted and considered universally best. Many philosophical differences exist among the pit planners concerning the use of different methods and it appears that resistance is very strong towards accepting other techniques if you are a believer in one. Whatever the case might be, the pit parameterization technique for the ultimate pit limit design is the latest and takes a different approach than its predecessors. There are already a number of papers which discuss the concepts involved (Francois-Bongarcon, 1976; 1978; 1980; 1981); however, the aim of this paper is to fill in some of the gaps which are thought to be missing in the previous discussions and, in addition, to present the recent research done on the subject at the Centre de Geostatistique de l?Ecole de Mines de Paris in Fontainbleau, France. This paper is divided into two parts. The first part will discuss practical aspects and interpretations of pit parameterization concepts with- out using mathematical or theoretical arguments; the reader who is interested in the theory should refer to Francois-Bongarcon (1978). The second part will present an approach to obtain a complete double parameterization of reserves using an inexpensive (computer costs) single parameterization algorithm. A case study of this approach is also included.

Jan 1, 1982

By M. L. Smith, G. Karunatillake

Lead-zinc production at MIM, Mount Isa includes three mines, a lead concentrator, zinc filter plant and lead refinery. Lead production is vertically integrated with lead-silver bullion shipped from Australia to London for refining. Zinc is sold as a concentrate. All three mines have reached varying states of maturity mining a multitude of orebodies having significant variation in grades and metallurgical recovery for three metals. Based on current levels of measured resources, the remaining project life is at least ten years. The objective is to schedule production over the life of all three mines so as to maximize the present value of the complex. Additional scheduling complexity arises out of the implementation of long-term schedules, capital expansion projects for both mining and processing, the presence of substantial inferred reserves and interactions with MIM copper production. A large-scale, time-dynamic, life-of-complex Mixed Integer Program (MIP) production schedule was formulated to optimize lead/zinc cash flow based on a detailed life of project production scheduling study. The requirements for such a study are detailed herein. The operational feasibility of the MIP solution is compared against a non-optimal approach to strategic life-of-mine scheduling. The strategic planning emphasis placed on the MIP is compared to the implementation of a life-of-mine schedules at Mount Isa using spreadsheets and other popular commercial mine schedulers.

Jan 1, 2003

By Brian R. Zuckerman

The Capitol Area East End Complex is currently being constructed under contract with the State of California Department of General Services on two sites adjacent to the grounds of the California State Capitol Building in downtown Sacramento. The complex will consolidate the headquarters of the Departments of Health Services and Education, which currently occupy several facilities located throughout Sacramento. When completed in 2003, the complex will be the largest civic office project in California history, with approximately 1.5 million square feet of office space and housing nearly 6,300 state workers. The total project is being constructed on five separate blocks in downtown Sacramento, Blocks 171 through 174 and 225. Separate design/build contracts were executed for the construction on Blocks 171 through 174 and the construction on Block 225. The scope of this paper is limited to construction on Blocks 171 through 174, which comprise a square, two blocks on a side, bounded by 15th, 17th, L, and N streets, located immediately to the east of Capitol Park and the State Capitol Building, as pictured in the image shown below.

Jan 1, 2002

By William Reisz

Over the years as surface mining operations have become more sophisticated, angle drilling has become a more popular blast design technique, especially in areas where overburden and stripping ratios have increased. Another method of blast design is the staggered pattern, which greatly improves explosives distribution within the blast. While both methods present some engineering challenges, this paper will discuss how the two methods can be combined to enhance fragmentation, improve cast percentage, drill production ratios and highwall control. A practical engineering approach will be presented as well as a discussion on the discipline required to maintain a quality blasting plan.

Jan 1, 2002

By P Goblet, S A. Séguret, E Cordier, A Galli

In salar-type deposits, lithium grades can be measured by bailers introduced at different elevations in the drill holes at locations where, later, the brine will be pumped out to recover the metal. When they are duplicated, these a priori rudimentary measurements may show large differences without indicating whether this is due to the procedure itself or to some physical causes linked to the dynamic behaviour of the salar (seasonality, rainfall, underground flow etc). In the reservoir presented in the paper, the problem is complicated by the double lack of stationarity of the lithium grades: the grades not only increase importantly with the depth but at the same time their fluctuations decrease, making it necessary to use non-stationary geostatistical techniques to simulate them. Reservoir simulation is developed in two steps: first, geostatistical simulations of the lithium grade create possible realisations of the reservoir; then, each geostatistical simulation is followed by a pumping simulation that calculates, at each drill hole of a given extraction scenario, the lithium produced each year over 40 years. For the set of 100 simulations produced in this way, a scenario reduction is made to choose the five most representative simulations where more complex calculations will be carried out (for example, changing hydrogeological parameters such as porosity and permeability, or the elevation of the filters, the number and the location of the pumping and the reinjection drill holes etc). The paper first presents an analysis of the geostatistical model sensitivity to the grade uncertainty when measured by bailer. Among the 100 measurements at our disposal covering the future production domain, 50 per cent are duplicates measured at the same place but at different times. They are randomly sampled to produce five subsets of 75 values, which will constitute the future 3D conditioning points for the geostatistical analysis and the simulations. For each subset, trend, standard deviation and variogram models are fitted, leading to five sets of 20 geostatistical simulations of grades. In this way, the reliability of the different parameters involved in the procedure is evaluated, as well as its impact on the pumping results. Then, a reconciliation study is conducted between the non-stationary nugget effects encountered in the 3D variograms of the lithium grade and a pure statistical analysis of 25 duplicates measured at different locations and/or different times. The result is that if the nugget effect reaches 20 per cent, which is the case of three conditioning subsets out of five, the reconciliation is good and the nugget effect of the variogram model represents the bailer uncertainty, ie the measurement error. Since the geostatistical simulation incorporates a nugget effect, it handles the bailer uncertainty and the impact on the produced metal is included in the evaluation. The final conclusion is that, after the hydrogeological pumping simulations, the initial differences between the five geostatistical models do not influence the final results: lithium grades measured by bailers can lead to a robust evaluation of the extractable resources, a conclusion that conflicts with conventional wisdom.CITATION:Séguret, S A, Goblet, P, Cordier, E and Galli, A, 2017. Bailer uncertainty evaluation in a lithium salar deposit, in Proceedings Eighth World Conference on Sampling and Blending , pp 395–402 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By George G. Goble

The use of augercast piles has been limited by the engineer's concern for the structural quality of the installed pile. The nature of the pile is such that its final structural continuity is very dependent on the skill of the personnel that do the installation. Thus, NDT methods have been used to verify integrity and when problems are indicated the available solutions are usually quite costly. If information were available during the pile installation so that immediate steps could be taken to correct perceived problems, the concerns of the engineer could be addressed and the system would gain increased reliability. Pile Dynamics, Inc. has developed a quality control system, the Pile Installation Recorder for Augered Cast-in-Place piles (PIR CFA). This system consists of the following devices as shown in Figure 1. 1) The Control Unit powers the sensors, conditions the signals from the sensors, records all measurements, takes input information from the operator, displays the results, and stores the recorded data on a flash card for later permanent storage and processing. During the use of the system all of the results obtained during a test are seen during recording and can be reviewed on the screen again after completion of the installation. The ability to review the measured information makes it unnecessary to print a copy in the field. Since printers often give difficulty in the construction site environment the ability to review the results quickly after completion of the installation is an important capability.

Jan 1, 1997

By W. R. Hibbard

Evidence is presented which confirms previous findings that models of solution strengthening depending solely on lattice parameter changes are incomplete. Direct evidence for the Suzuki interaction of chemical effects was obtained from alloys with constant lattice parameter, for which solution strengthening was nearly independent of temperature from 300° to 20°K. SOLUTION hardening principles have been reviewed recently by Parker and Hazlett.' In addition, the interactions of dislocations and solute atoms were reviewed by Cottrell.' It is not proposed to review this information again here, but to refer only to those details which are pertinent to the developments which have occurred since these papers were published. Literature Survey To set the stage, it has been known for some time that solid solutions are stronger than the pure parent metals, and that the strength increases with increasing amounts of alloying element. One of the most extensive earlier investigations was that of Lacy and Gensamer,3 who reported that the solid solution strengthening of iron is a power function of the composition, that the relative strengthening is a function of the solubility limit, and that the rate of strain hardening is a function of the amount of solution hardening. Thus, the slope of the plastic portion of the stress-strain curve increases with increasing yield strength. An approach to the development of principles resulted from work by Gulyeav,4 who reported that the strengthening effect of solid solution alloys is periodic in character when plotted as a function of the atomic number of the solute. A more quantitative approach was to relate the amount of solution hardening to the lattice parameter of a solid solution. This was done quite early by Norbury,5 and later by Brick, Martin, and Angier,6 Frye and Hume-Rothery,7 and French and Hibbard. This relationship is only approximate in character. The next development was to relate the amount of solution hardening to lattice stress, as proposed by Frye and co-workers.9 They calculated what they called ionic overlap from the lattice parameter changes represented as a change in volume, using Bridgman's hydrostatic compression equation. The resulting correlation was somewhat improved as compared to the simple correlation with lattice parameter. The next step was carried out by Dorn, Pietrow-sky, and Tietz,10 who suggested an effect of valence differences in addition to the effect of lattice parameter. Their proposed parameter shows flow stress as a single valued function of the concentration and a relationship involving these two atomic variables. In addition, they contributed new data on the temperature dependence of solution hardening which indicated that it was a strong function of temperature for aluminum alloys. Allen, Schofield, and Tate11 carried the valency effect even further by reporting data indicating that with a given solvent element the stress-strain curve is a function of electron density, entirely neglecting the size factor, which varied by a factor of two. This evidence led to a quantum mechanical calculation by Cottrell, Hunter, and Nabarro,12 based on the formation of a dipole around an edge disloca-

Jan 1, 1959

By Vaughan J. P

The Pegmont deposit is a stratiform Pb-Zn sulphide body occurring in a thin, iron-rich metasedimentary unit situated near the top of the Kuridala Formation, a part of the Mary Kathleen Group of the Middle Proterozoic"Eastern Geosyncline" succession of the Mount Isa-Cloncurry district. The deposit appears to have developed in a shallow basin or depression on a sea or lake floor.Detailed chemical and mineralogical study of seven diamond drill cores through the ore horizon shows that in addition to galena and sphalerite the orebody contains a large range of iron-rich silicates and aluminosilicates.Further, five drill cores selected to represent a section from basin centre to basin edge exhibit clear and systematic chemical and mineralogical changes in the ore horizon in both a vertical and, most importantly, ill a lateral sense.Reconstruction of the sedimentary environment of the ore horizon as a whole shows this to be a silicate facies of a phosphatic, manganiferous iron formation or, more accurately, of "ironstone" in the sense of James (1966, U.S. Geol. Surv. Prof. Paper 440, chapter W).On the basis of both mineralogy and chemistry this silicate facies may be subdivided into three microfacies according to the dominant iron silicates characteristic of each: a fayalite microfacies, a hornblende-clinopyroxenemicrofacies, and a garnet microfacies. Significant Pb-Zn sulphide concentrations are confined almost entirely to the fayalite microfacies.

Jan 1, 1979

By W. W. Roepke

The Bureau of Mines has developed an interactive computer program that enables mine operators and others to identify the effect of cut-ting system changes on relative dustiness at the face. The program, which simultaneously evaluates machine parameters, coal seam parame-ters, and operator-controllable parameters, was developed for use on any microcomputer using BASIC programming language. The program allows the user to change one or more of the cutting system parameters at a time to see how these changes affect relative dustiness. A complete program listing and flowchart are included along with operating in-structions and sample outputs. An example showing how to use the program is also included.

Jan 1, 1985

Deep level block caving as a mining method is becoming more popular due to the fact that it is the lowest cost per ton underground extraction system. However, many block caves do not achieve their full potential due to draw horizon instability. In this paper five design rules are given to overcome this problem. The design rules described are applicable for slusher and trackless block caves where the operational depths exceed 500 metres.

Jan 1, 1999