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By Joseph M. Kurtak

The Bureau of Mines conducted a four year (1985-1988) mineral assessment of the Juneau Mining District in southeast Alaska as part of its ongoing statewide mining district evaluation program. Following an extensive literature search, the Bureau investigated mines, prospects, and mineral occurrences in the area. This report describes the results of Bureau work in the Eagle River area of the Juneau gold belt; a component of the Juneau Mining District comprising 87,000 acres between the Mendenhall Glacier and Berners Bay. Gold and silver have been the only metals having significant production from the area and occur mainly in quartz stringer and fissure type veins hosted by phyllites, greenschists, greenstones, altered diorite dikes and quartz diorite gneiss. Gold also occurs in several small placer deposits. Approximately 21,100 oz of gold and nearly 9,000 oz of silver were produced over a 60 year period. Currently, the only mining activity consists of some exploration and minor placer gold production. Inferred and indicated lode gold resources having mineral development potential total approximately 796,000 tons with a weighted average grade of 0.22 oz/ton gold.

Jan 1, 2011

By G. van Aswegen

Seismic monitoring became commonplace in the deep South African gold mines in the early 1990’s. The discipline has, to a large extent, developed beyond the ‘research’ stage, and a ‘Guide to Seismic Monitoring in Mines’ has been accepted by the Department of Minerals and Energy1. Although ongoing research is a requirement for the achievement of all the objectives of seismic monitoring in mines, sufficient knowledge exists to apply seismic monitoring for routine seismic hazard assessment as an aid to risk management. The design and management of seismic monitoring systems can be tested against requirements spelled out in the ‘Guide’. Assuming the seismic monitoring system performs as per requirement, the best practice for routine seismic hazard assessment in mines includes • Long term seismic hazard assessment: through back analysis of seismic data and correlation with numerical modelling output, reasonable tests for planned mine designs are possible. • Medium term seismic hazard assessment: o Spatial analysis through contouring of seismic strain related parameters, with superimposed contours or event plots of stress related parameters allow the delineation of potential instabilities in space. o Quantitative and statistical analyses of seismicity in smaller spatial units (usually encompassing production sites) allow the comparative seismic hazard rating of different areas/sites so that rock engineering input and risk management can be optimised • Short term seismic hazard assessment relies mainly on time history analyses of particular seismicity parameters. The temporal patterns are controlled by a combination of temporal and parameter filters, the optimisation of which determines the success rate.

Jan 1, 2003

By S. Mostaghel, S. Nicol, M. Y. Solar

Once upon a time, the process engineer developing the design criteria for a new saprolite ferronickel smelter had it easy: most ores were around 2.5% Ni, with a Fe/Ni ratio of 4 to 5 and a SiO2/MgO ratio of about 1.6; to use the French word: garnierites. The ferronickel grade selected was the conventional 20 to 25% Ni and the impurity levels could be predicted from well established [C], [Cr] and [Si] vs (FeO) graphs. However the process engineer can no longer depend on statistics to design smelters: Ni grades are decreasing while the goethite contents are increasing; SiO2/MgO ratios vary from 1 to 3; and Al2O3 concentrations are reaching levels that cannot be ignored. Mechanistic models must be developed to select or predict essential parameters such as kiln and furnace reductions, ferronickel grade, slag losses, metal and slag liquidus, operating temperatures, etc. But these models must be simplified so that they can be used on a routine basis; and they must be calibrated against a wide range of commercial operations in order to yield the most realistic predictions possible. The present paper proposes one possible approach, using FactSage as a basic source of thermodynamic data. The predictions thus obtained are compared to actual performance for two well documented operations, as well as to the predictions made with other tools that might be more accessible.

Jan 1, 2014

By Dhanaji S. Chavan, Thallak G. Sitharam

"It is well known that sites comprising of saturated loose sand undergoes large deformations, due to liquefaction, during seismic shaking. To cope with this, different mitigation techniques such as vibroflotation, deep dynamic compaction, compaction grouting, deep soil mixing etc. have been used in practice. However, as all these methods are costly, a new mitigation technique is required. Air injection has emerged as a new mitigation technique in which air is injected into the saturated loose sand. The introduced air makes the pore fluid mixture compressible and results into decrease in the generation of excess pore water pressure during seismic shaking. This paper reviews the laboratory and field studies performed to investigate the effect of air injection on liquefaction resistance. In addition to this, previous research in the direction of desaturation has evolved different techniques to generate gas in saturated sand. These techniques have also been discussed in the present paper. All the field and laboratory studies have shown that even a slight decrease in the degree of saturation increases the liquefaction resistance significantly.Keywords: desaturation, air injection, liquefaction resistance, pore pressureINTRODUCTIONEarthquake events in the past, caused liquefaction of loose saturated sands at many sites in the world. The consequence of liquefaction varied from small deformations to catastrophic failures such as flow slides, lateral spreading, sand boiling etc. (Kramer, 1996). To reduce the liquefaction potential of such soils, different mitigation techniques have emerged across the world. Some of the most widely used mitigation techniques are vibroflotation, deep dynamic compaction, compaction grouting and deep soil mixing (Idriss and Boulanger, 2008).Yoshimi et al. (1989) found that the liquefaction resistance of partially saturated sand is significantly higher than that of saturated loose sand. Further, Pietruszczak et al. (2003) proposed desaturation of the saturated loose sand as a new liquefaction mitigation technique. It is observed that the liquefaction resistance of sandy soil is enhanced significantly owing to the desaturation caused during construction of sand compaction piles (Ishihara et al. 2003). Over past few years research is being carried out on desaturation of sandy soil and its liquefaction resistance ( Ishihara et al. 2003; Okamura and Soga 2006; Yegian et al. 2006; Yegian et al. 2007; Takemura et al. 2009; Eseller-bayat et al. 2013; He et al. 2013; Marasini and Okamura 2015; Zeybek and Madabhushi 2016). As a result of this, different techniques of desaturation have also emerged. Different studies conducted in this direction and their outcome has been discussed in the section to follow."

Jan 1, 2017

? Founded In 1953 ? Mining growth of 83% since 2007 ? We produced over 1 million ounces of Au in 2012 ? We Forecast of 20% Au production in 2013-2015 ? We have paid a dividend 31 years consecutively. Terry Reid ? 1992-93 Electrical Technical, College ? 1994-95 On the job placement College ? 1998 ? Licensed Millwright, ? 2005-12 ? Maintenance Reliability Planner ? 2012- Present Business Process Owner

Aug 1, 2013

By Andrew Port, Ali Ghandeharioon

Nonlinear seismic deformation analyses using the finite difference program FLAC were performed for a wastewater treatment plant to estimate foundation displacement and performance of two proposed trickling filters during the 2475-year event design earthquake. The effective stress based constitutive model UBCSAND, which captures the cyclic behavior of both the “sand-like” and “clay-like” materials, was used to model the dynamic response of the soil strata. Dynamic analyses of the site indicated that in absence of ground improvement or deep foundations beneath the proposed trickling filters, those structures would undergo horizontal displacements in excess of 1 m and short-term differential settlement gradient of about 400 mm over 50 m as a result of seismic and post-seismic settlements. Three mitigation options were considered for limiting the seismic displacements and differential settlement gradients of the proposed trickling filters. These alternatives include vibro-replacement stone columns, vibro-replacement stone columns plus supplementary cutter soil mixing (CSM) configurations, and pile foundations. Various layouts for each mitigation option were considered including the lateral extent of the ground improvement, CSM walls and pile spacing. Seismic horizontal and vertical displacements of the proposed structures as well as post-earthquake consolidation settlements due to dissipation of excess pore water pressures in soil layers were assessed in all the analysis alternatives. The analyses indicate that all the alternatives considered have the potential to provide a comparable level of seismic and post-seismic performance. However, for similar performance levels, the ground improvement options need to extend well beyond the edges of the proposed structures, while the piles can be limited to just beneath the footprint of the structures. INTRODUCTION Annacis Island Wastewater Treatment Plant (AIWWTP) is owned and operated by Greater Vancouver Sewerage and Drainage District and services a population of approximately 1 million people in Vancouver, British Columbia. Wastewater is generated by residential, commercial, and industrial sectors and the treated effluent is discharged to Annieville Channel of Fraser River on the south side of Annacis Island. AIWWTP is located on a 51-hectare site and was commissioned in 1975 as a primary treatment plant, but has had two major expansions to meet the population growth needs, and to improve the treatment process efficiency through the provision of secondary treatment of the liquid stream. The current expansion includes construction of additional solids contact tanks and secondary clarifiers. Future expansions include the construction of proposed additional trickling filters. New expansion structures are required to be designed for post-seismic operation after the 2475-year event design earthquake.

Jan 1, 2018

By Sergei Decterov, Peter Hayes, Evgueni Jak, Taufiq Hidayat, Denis Shishin

Copper smelter operations around the world are under sustained pressure to reduce costs and increase output. Through the provision of reliable data on fundamental properties of the chemical systems the opportunities for improvements of industrial copper production can be identified. Experimental and modelling studies on phase equilibria, thermodynamics of copper slag/matte/metal/gas systems have been combined into an integrated research program undertaken at PYROSEARCH. Experimental phase equilibria studies involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of compositions of equilibrium phases with electron probe X-ray microanalysis (EPMA). Thermodynamic databases development and modelling is undertaken using the computer package FactSage in conjunction with advanced models used for complex solution phases. Progressive development of these research methodologies has brought significant advances in characterisation of these complex systems, including a new optimised thermodynamic database for the copper-containing slag system Cu2O-Al2O3-CaO-FeO-Fe2O3-MgO-S-SiO2.The new data and models can now be applied to assist in improvements of the processes. The effects of changes to chemistry and process conditions within the smelting reactor can be examined. Several examples of new descriptions of the phase chemistry of the Cu2O-CaO-SiO2 and Cu2O-FeO-Fe2O3-SiO2 systems in equilibrium with metallic copper showing calculated and experimental data are presented.

Jan 1, 2014

By M. Sears, W. H. Su, J. Wickline, M. A. Van Dyke, G. Esterhuizen, Z. Khademian

It is commonly recognized that seismicity can be induced by rock failures or slip along geologic structures around mining excavations. The unpredictable nature of these events and their proximity to the working area may raise safety concerns in underground mining operations. Modeling can be a useful tool for estimating seismic potential for a given mine layout, but the challenge is to detect a seismic event and estimate its intensity in the model. One well-documented approach is to monitor the variation in the energy content of the model and record potentially damaging seismic events when there is a significant release of energy. Researchers from the National Institute for Occupational Safety and Health (NIOSH) employed this approach using 3DEC modeling software to simulate the anomalous seismic events that occurred in a deep longwall mine in Virginia in 2005. A four-panel model of the mine was constructed utilizing a 2D cross section at the location of the mining face at the time of the event. Seismic potentials associated with the development of each panel are evaluated by recording the seismic energy released during the simulation. The results demonstrate the occurrence of two relatively significant events during the mining of the last panel, which are consistent with the historical observations at the mine.

Apr 26, 2022

By Mina M. Shinouda

Brightwater West (BT4) represents the state of the art in utility tunneling, namely a long relatively small diameter, soft ground tunnel, with no intermediate shafts, under significant groundwater pressures, requiring very precise survey control in order to hit a small exit window. The tunnel is over 6.4 km (4 miles) in length, is expected to encounter active earth pressures of over 5 bars in glacial geology, and a planned hole through into a shaft eye constructed at 45.7 meter (150 feet) below the water table. Despite the fact that all of these challenges have been previously overcome in larger diameter tunnels, the technical solutions are much more challenging in a smaller diameter due to the lack of space available for implementing the equipment and techniques required. In addition to the technical challenges, the project is faced with many of the constraints designed to minimize the impact of these types of projects on the neighboring community and environment. The work shaft for BT4 is within 15.2 m (50 feet) of Puget Sound and is on a site that was previously occupied by petroleum storage tanks, and all of the tunnel muck has to be removed from the site by barge as trucking is not allowed by contract. The paper addresses the work performed during the preparation for tunneling stage of this project both in assembling the TBM and in preparing the site for its arrival.

By H. P. Greenwald

[For sarno years past the Safety in Minbr. Resaarch J30ard of Great Bri tr-dn ha:1 been making ar.. intensive Gearch for, traterials that \.'ould be 1!\ore ef-ficient than rock dust and th t 'could l1eplace it Jholly or in El:}rt as a muans of prevEll'ltine the propa 'tion' of 'c63.1~dust exnlosions in. mines21 In the course of this \o.'ork several rock c.ur--ts md numerous inorganic compounds I,/ere tested. The result w place incombus.ti ble substFlnces in two main groups~ (1) r.:ho se who sa effect' in suppre aeina Jlihe cor.lbustion of coal dUDt i 0 pro-]

Jan 1, 1940

By Michael W. Neill, O&apos

The engineering profession generally does not accept vibro-driven piles as bearing piles unless their capacities can be verified by restriking with an impact hammer, which significantly reduces the economic benefits of vibratory driving. In part, the concern for capacity development in piles driven by vibration arises out of observations that vibro-driven piles do not develop capacities equivalent to those driven by impact (e. g., Mosher, 1987). Nonetheless, if capacities are predictable, vibratory installation may be more cost effective than installation by impact, due to savings in time of installation, even if capacities are lower than those of impact-driven piles. Throughout the past few decades, a number of attempts have been made to develop capacity prediction methods for vibro-driven piles, mostly along the same lines as methods for impact-driven piles. That is, (1) totally empirical formulae, (2) power balance / power transfer formulae, and (3) "time domain-nonlinear" (TDN) computational procedures such as the wave equation. Some of the formulae have been based partly on field experience, but the majority have been developed from simple theoretical models with parameters evaluated from laboratory studies. Neither these formulae nor the TDN solutions have been systematically checked (or modified) by recording appropriate field data over a variety of site

Jan 1, 1989

By A Scott, I Onederra

A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful empirical or engineering models are currently available to blasting engineers and consultants, while more sophisticated approaches using mechanistic and numerical descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The fragmentation resulting from any blast will be heavily dependent on the properties of the rock mass being blasted; however, most empirical models rely on ‘rock factors’ generated from simple rock mass properties to describe the influence of the rock on the blasting outcome. In contrast, mechanistic models need explicit rock mass properties that require sophisticated laboratory measurements and detailed structural data if realistic outcomes are to be generated. The fragmentation modeller is caught between excessively simple rock mass descriptions for the empirical models and excessively complex data requirements for the mechanistic models.This paper briefly reviews the basis of a range of fragmentation models and the rock mass properties on which they rely. Shortcomings in the way that the mining industry tends to characterise the blasting properties of rock are discussed and some practical approaches are described to quantify these properties in both operating and greenfield mining environments. Case studies are presented where specific additional breakage properties and modelling features have been needed to generate a useful description of the fragmentation achieved.CITATION:Scott, A and Onederra, I, 2015. Characterising rock mass properties for fragmentation modelling, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 149–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By N. Hiroyoshi, R. D. Corpuz, M. Ito, Hokkaido University, C. B. Tabelin, S. Veerawattananun

"Acid mine drainage (AMD), the very acidic and heavy metal-contaminated leachate generated when pyrite-bearing rocks are exposed to surface oxidizing conditions, is a serious environmental problem encountered after the closure of mines and mineral processing operations. In this study, we investigated the effects of soluble phases and metallic oxides, which are commonly found in strongly weathered pyritic wastes, on pyrite oxidation. Strongly weathered pyrite containing melanterite (FeSO4·7H2O) as the main soluble phase was obtained from Furikusa mine, Japan. The sample was washed using two methods to vary the relative amounts of melanterite in the sample. The effect of metallic oxides on pyrite oxidation was evaluated using ultrapure hematite suspensions. Our results showed that under acidic conditions, the effect of soluble salts on the oxidation of pyrite was stronger than hematite. More thorough washing of the sample resulted in the formation of an arsenic-bearing iron-oxyhydroxysulfate coating that minimized pyrite dissolution. This oxidized layer became relatively thicker and mechanically stronger when hematite was introduced after the more thorough removal of soluble salts. Characterization of this “coating” coupled with geochemical modeling suggest that it is most probably composed of two materials: schwertmannite and scorodite. Based on these results, a new approach to suppress pyrite oxidation by directly using iron-oxyhydroxysulfate as coating material is introduced.INTRODUCTION Acid mine drainage (AMD), the very acidic and heavy metals-contaminated leachate produced in closed/abandoned mine sites (Evangelou, 1995), mineral processing and coal cleaning tailings (Evangelou, 1995), and tunnel construction waste rocks (Tabelin and Igarashi, 2009, Tabelin et al., 2012), is one of the oldest and probably the most serious environmental problem of anthropogenic origin. When released to the environment, it rapidly pollutes river, soil and groundwater systems leading to the destruction of affected ecosystems. AMD is produced when pyrite (FeS2), one of the primary gangue minerals in sulfide ores and coals, is exposed to oxidizing conditions as illustrated by the following reactions:"

Jan 1, 2016

By M. Kuchta, S. Iverson

INTRODUCTION Underground blasting with perimeter damage control can reduce the requirement for loose rock scaling and reduce the risk of ground-fall injury. In previous work Johnson and associates (2010) from the National Institute for Occupational Safety and Health (NIOSH) developed a rock blasting perimeter damage and control design method included in the DRIFT software tool (NIOSH, 2018). This blast design software tool utilizes current methods of perimeter blasting with the added design element of a buffer row coordinated with the perimeter row to reduce perimeter damage. The coordination is in applying one of several blast damage models to calculate the damage extent for each production, buffer, and perimeter blast hole in the design. The calculated damage is then applied to the spacing between the blast holes. The basis of the buffer row design is the practical damage limit and is supported in this paper with computer models of signature blasts and full blast rounds using PFC2D (Itasca Consulting Group, Inc., 2018). Practical damage limit The practical damage radius (Rd) is not to be confused with burden. The practical damage extends toward the burden side and inward into the rock mass. For all practical purposes, the practical damage radius equals one half the burden (Hustrulid, 1999). The maximum extent of radial crack damage around a blast hole (Rcrack) and the maximum extent of radial crushing damage (Rcrush) are illustrated in Figure 1. A “practical” radius of damage (Rd) lies between the crushing limit and the cracking limit. The “practical” damage means that if the rock mass lying outside of the practical damage circle were removed, the rock remaining within the circle would easily break apart. Blast pressure and strain Work by Johnson (2010) and associates included signature blast tests in large concrete blocks. A signature blast test in concrete as exampled by strain data in Figure 2 was designed to monitor the dynamic strain at incremental distances from a single fully coupled blast hole, measure crushing and radial cracking extent by wire-sawing to expose the damage, and relate the damage to overbreak that is common in underground blasting. The initial slope or rising strain as the stress wave passes by the strain gages shows very high strain and strain rates close to the single blast hole. Since the derivative of strain versus time is strain rate, a line tangent to each of the strain curves at the maximum strain rate is drawn and the strain rates identified. The high strain rates were then plotted on a semi-log in Figure 3 to show a linear trend. The strain rate is greater than 100 s-1 within 20 cm from the blast hole for the signature blast experiment. The strain rate at the blast hole wall is projected to be 300 s-1. Figure 4 illustrates the damage in the NIOSH block exposed by a wire saw cut.

Jan 1, 2019

"INTRODUCTION AND ACKNOWLEDGMENTSAt the request of the lessees, the Pearl tract was examined in February 1946, by Otto Ruhl, an engineer of the Bureau of Mines. From the evidence of old drill logs and from the few available records of mining operations on the Pearl and the adjoining Trussel (Big Tom) tract, it appeared that a relatively small churn-drilling program might develop enough lead-since ore to justify resumption of mining. In March 1946, funds were allotted for churn drilling, and the work was begun the following month. Ten holes totaling 1,933 feet were completed before the close of the project in August 1946. The work was under the general supervision of C. H. Johnson, chief, Rolla Division, Mining Branch, and under the direct supervision of the Bureau project engineers. 3/In its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to our national security and economy, It is the,of the Bureau to publish the facts development by each project as soon as possible after its conclusion. The Mining Branch, Lowell B. Moon, chief, makes preliminary examinations and conducts investigation of mineral deposits. The Metallurgical Branch, O. C. Ralston, chief, participates in this program by making beneficiation tests and analyses. In the present project, no metallurgical tests were made, and for the sake of speed the samples taken were analyzed by a local commercial assayer. 4/"

Jul 1, 1947

By T. Wettainen

Malmberget town is located in northern Sweden, approximately 70 km north of the Arctic Circle. Parts of the town overlie more than 20 iron orebodies, consisting mainly of magnetite with smaller quantities of haematite. The mine is operated by the mining company LKAB. Mining started in the 17th century, but not until the railway to the coastal city of Luleå was completed in 1888 did large-scale production commence. Around 1920, mining proceeded underground and today sublevel caving is the only mining method used. Sublevel caving causes subsidence of the ground surface, and buildings and residential areas have been relocated due to the mining activities for more than 50 years. The number of seismic events accompanied by strong ground vibrations is now increasing. In 2008 the mine received a permit from the Environmental Court of Sweden to increase production to 20 Mt of crude ore per year. A prerequisite for the permit was that the mine conducts a number of investigations regarding the environmental impact on the residents of Malmberget. One of these investigations concerned how seismicity will change as production increases and what measures could be taken to reduce inconvenience to the town residents. Today the mine possesses an extensive seismic monitoring system with more than 180 underground and surface geophones. For this study, eleven seismically active volumes in Malmberget mine were identified, and for each of them, a yearly future maximum magnitude interval was estimated based on the current production plan. Relationships between historical seismic events and measured ground vibrations in the town of Malmberget were established, and future ground vibrations caused by expected seismic events were estimated using a probabilistic approach. The outcome was the number of intervals of expected ground vibration per year and per monitoring point. Possible measures to reduce inconvenience for the town residents include blast restrictions, sequencing, and possibly preconditioning. The ultimate long-term solution is an almost complete relocation of Malmberget town. This process has recently been formalized and LKAB is taking an active part in realizing this goal.

Jan 1, 2014

By Stefan Wallner, Andreas Filzwieser, Stefan Konetschnik, Reinhard Preiss, Iris Filzwieser

"Process Safety Management for METTOP means avoiding risks as far as possible - but also dealing with the residual risk by using all existing management tools or external assistance, if required. The presented paper has two parts. The first one introduces a new and very safe cooling technology for metallurgical furnaces. The second part shows how to deal with the residual risk as well as minimize it by using the tapping area of an electric arc furnace as an example.Today more and more intense furnace operations require effective cooling in order to achieve low refractory wear and good furnace lifetime, making cooling technology an important aspect of furnace operation. However, the use of water - today’s standard cooling medium - has some disadvantages, as it can cause problems both during furnace start up and operation, namely hydration problems, corrosion, and explosion.To overcome the disadvantages of water, a new cooling technology using an alternative cooling medium, namely ISIS B (a special kind of ionic liquid) was developed. The main advantage of ISIS B is the fact that no explosion occurs when this liquid comes in contact with molten metal. The working temperature range of ISIS B of 50 to 200 °C results in other advantages as there are no corrosion problems and no risks of hydration.The fact that no explosion occurs when ISIS B contacts molten metal leads to a revolutionary solution for the metallurgical industry in terms of safety. Especially in critical areas - like tap-holes - new safety standards can be achieved.Together with the TÜV Austrian Holding AG a risk analysis was done for a water cooled tap-hole as well as for a tap-hole cooled with ionic liquids. It is shown that using the new technology the risk can be decreased dramatically and the importance of a best available technology is described."

Jan 1, 2014

By M. J. Sanzotti

This paper examines the potential for controlling longwall-induced subsidence by pneumatically backstowing the void created by mining with waste rock, and having the process scheduled as a unit operation of the mining activity. Based on a review of background literature, interviews with representatives of various mining companies, public-interest groups, and state and federal regulatory agencies, a hypothetical case-study evaluation of pneumatic stowing in a southwestern Pennsylvania mine site was conducted. The study indicated that current stowing technology cannot keep pace with the production potential of U.S. longwall systems. Further, at the case-study mine site, concomitant stowing would reduce subsidence by only 50% of that incurred during full longwall caving, the longwall coal production rate would decrease from 4000 tons per shift in the non-stowing case to 1500 tons in the stowing case, and a preliminary cost analysis reveals that pneumatic stowing would add $5.25 to $10.50 to the operating cost of producing a ton of coal at the case-study site.

Jan 1, 1995

By Mary C. Nodine, Michael P. Walker, Paul Eggers, Donald E. Aubrecht

The CANALSIDE commercial development in Buffalo, New York serves to revitalize the former site of the Buffalo Memorial Auditorium, adjacent to Lake Erie. The Auditorium was constructed in 1940 and founded on steel H-piles driven to limestone bedrock. After decades of professional sport and entertainment events, the “Aud,” as it was locally known, was closed in 1996. It sat vacant until it was demolished in 2009, at which time plans were made to revitalize the area with shops, restaurants, and a historic replica canal. The only portion of the Aud that was left intact was a subbasement boiler room. The subbasement was renovated in 2014 and has since been used to house water and ice making equipment for the historic replica canals, which boast recreational ice skating in the winter. The subbasement floor was about 10 feet below groundwater and the Lake Erie water level. The floor consisted of an approximately 4-foot-thick layered inverted waffle slab system, with reinforced concrete grade beams and concrete infill between the grade beams. A waterproofing membrane was located near the base of the slab. There were no major seepage issues in the subbasement, so the existing waterproofing membrane was assumed to be intact and performing adequately. A four-story building housing a children’s museum was proposed to be constructed directly above the subbasement. The loads imparted by the new building would exceed the capacity of the existing piles, so it was determined that drilling micropiles through the subbasement floor would be the most practical means of supporting the new building. Drilling through the existing slab and waterproofing system was a concern due to the challenges of controlling water during construction and the importance of maintaining the integrity of the permanent waterproofing system.

Jan 1, 2018

By K P. Tully

In August 1996 a Microseismic Monitoring System developed by ISS International Limited was installed at the Pasminco Broken Hill Mine -Southern Cross area. The project aims were to:Assist in daily safety management in a mine environment which exhibits one of the highest occurrences of microseismic activity recorded in the Australian mining industry. Be used as a proactive tool in design of future development and stoping. The project to-date has been an unqualified success in achieving both goals. Consequently the system is being expanded from 6 to 14 monitoring sites.

Jan 1, 1998