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By R. J. Sweigard

Three case studies were undertaken to investigate the role of land use potential evaluation in reclamation planning and to determine the impact of regional differences on the evaluation process. The three surface mines studied were representative of operations in the Appalachian, Interior, and Northern Great Plains provinces. The scope of the investigations included a survey of regional characteristics, a detailed investigation of the mining operations and site conditions, and an assessment of local land use planning activities in the area of the mine. Special attention was given to key factors that presently determine the use of reclaimed land. Also, for each case study, the postmining land use potential was evaluated using site planning principles. Specifically, the environmental, economic, and social impacts of several potential postmining land use plans were considered.

Jan 1, 1983

By Olli Haavisto, Lauri Koresaar, Navid Khajehzadeh

In recent times sustainable minerals processing is an important topic in research. Sustainable mining is linked with efficient use of energy and human resource in all process stages including beneficiation of the ore. Controlling and optimizing the recovery while preserving the grade of the concentrate is extremely important in flotation plants. This development requires new technological solutions and has given rise to the multitude of application areas for lasers. X-ray Fluorescence (XRF) and Laser-Induced Breakdown Spectroscopy (LIBS) are currently two of the predominant non-contact and direct analysing methods in industry. LIBS and XRF measurement techniques both have high capabilities for measuring elements. LIBS has a very simple and easy-to-implement spectroscopic setup, wider range of elements can be detected with online LIBS and measuring light elements is simpler by LIBS compared with XRF. It is of great interest to extract mineralogical information from the elemental results with no modification on the measurement setup. In order to achieve this, more advanced interpretation of the elemental peaks of LIBS spectra is required. Therefore, the major focus of this research is about measuring mineral concentrations from the elemental lines of LIBS spectra using advanced statistical methods. This accomplishment provides knowledge about mineral concentrations from the real-time assay data of the slurry LIBS analyzer. Consequently, this paper first discusses an analytical method called partial least squares regression leading to rapid mineral identification from the elemental contents of the LIBS technique. Then the technique is employed to analyze the mineral contents quantitatively through the information acquired from an on-stream LIBS slurry analyser. This can lead to many benefits such as rapid control of concentrate quality, enhanced recovery, saving time, energy and manpower.

Jan 1, 2016

By Sarah Ramp, Daniel V. Cacciola, Justin Labrozzi, Shafiq I. Siddiqui, Faisal Ahmed

"Construction of embankments up to 34 ft in height for twelve ramps and roadways needed for the New Jersey Turnpike Interchange 14A project required ground improvement. The subsurface conditions, consisting of up to 30-ft thick layer of highly-compressible peat and organic soils, would induce up to 8 ft of primary and 4 in. of secondary consolidation settlements to the embankments over a long period of time. Innovative ground improvement solutions were needed to meet unique challenges posed by the poor subsurface conditions, space and existing utility constraints, aggressive construction schedule, and massive size of the project. A variety of ground improvement techniques were utilized in six different zones of the embankments to limit settlements and ensure stability of the embankments. These techniques included preloading with surcharge and prefabricated vertical drains (PVD), load balancing using light weight fill, and concrete column rigid inclusions (RI). Additionally, augercast piles with load transfer platform were used under an existing bridge with low vertical clearance. An innovative approach consisting of preloading with surcharge and PVDs followed by installation of RI was needed in one of the six embankment zones with the worst, i.e., very soft, soil conditions. The design of the RI was performed by a specialty ground improvement contractor (SGIC) using Plaxis 2D and 3D softwares. The performance of the ground improvement systems was verified and monitored by load tests and instrumentations. This paper presents details of the ground improvement design, construction, monitoring results, and lessons learned, with a focus on the RI.INTRODUCTIONNew Jersey Turnpike Interchange 14A is located within the cities of Bayonne and Jersey City, in Hudson County, New Jersey. The New Jersey Turnpike Authority (NJTA) identified Interchange 14A as an area of mass congestion in need of redevelopment to improve the increasing demand of traffic and roadway safety. The New Jersey Turnpike Interchange 14A project included the construction of twelve (12) new roadways, in addition to the construction of four new bridges. The limits of construction are shown in Fig. 1.The fill height required to construct the roadway embankments varied from 2 to 34 ft. The proposed embankment side slopes varied from 6H: 1V to 2H: 1V. Additionally, mechanically-stabilized-earth (MSE) walls were utilized to retain the embankment fill along some segments of the roadways. As shown in Table 1, the proposed roadways were divided into six zones, based on location, subsurface condition, and embankment height."

Jan 1, 2017

By Donald Towse

Geothermal heat might become an important fuel for several reasons: (1) To substitute for other scarce and critical fuels. (2) Because it may be less costly to the user than alternate fuels. (3) Because its production may be more profitable than production of other fuels. (4) Or for a number of other more or less non-economic reasons such as convenience or because of less environmental impact. In competition with conventional and other non-conventional fuels, geothermal heat must score well on one or more of those points. This study first considers projections of energy needs in several United States economic sectors and the technical possibility of geothermal heat substituting for other fuels in those sectors. Then, reported and projected costs of energy from geothermal heat are compared with costs of other fuels to show the relative costs of fuels in several economic sectors. Relative costs are reported from a sample of real and hypothetical geothermal projects. The actual cost of energy will vary with each application and the particular circumstances of each geographic location.

Jan 1, 1975

By T Schrimpf, I Bryan

The life cycle of a mining project begins with initial regional exploration and ends with mine closure and rehabilitation. Between resource definition and the commencement of mine construction is the study phase. In this phase technical concepts and processes are defined, evaluated and assessed with the aim of establishing whether the deposit is economically feasible. The study phase usually involves various steps from a concept/scoping study to prefeasibility and ultimately definitive feasibility study. The complete study phase can take several years. Although the costs for studies are low in comparison to actual construction and operating costs of a mining project, they are significant especially for junior exploration and mining companies advancing projects to the point of being funded.The studies aim to determine selected parameters for the project, eg mining and processing methods, operating strategy, etc and provide a roadmap for project development ahead. Although mining studies are of the utmost importance for the mining project and the project owner, they are usually carried out using a conventional engineering approach: the consultant or design engineer works to a defined scope of work. The resulting design might be based on good engineering, but might often also fail to provide the solution for the project owner that delivers the best shareholder value. An alternative to this more traditional approach to project evaluation is what we have termed a value engineering approach. Value engineering is a creative, organised effort, which in the case of a mining study analyses the requirements of the study for the purpose of achieving the essential outcomes with the highest shareholder value. The outcome of a study is a concept that delivers the highest achievable value of the resource project and shows the way ahead to realise this value. Through a group investigation by experienced, multi-disciplinary teams the value of the resource is improved through the study of alternative options, methods and processes. The scope of the study is not limited to a narrowly defined engineering scope, but to the creation of value.The study commences with the identification of key value drivers and risks, based on the available information (drill data, geotechnical data, metallurgical test work, etc). This enables the quantification of key uncertainties, risks and value adding opportunities. Study efforts concentrate on key value drivers and are not unnecessarily spent on side issues. This approach can significantly reduce the time frame and costs for the study phase.This paper describes in more detail RMDSTEMÆs value engineering approach to mining studies and illustrates it with examples and case studies.CITATION:Schrimpf, T and Bryan, I, 2012. The application of value engineering principles to mining studies, in Proceedings Project Evaluation 2012 , pp 163-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Sylvain Picard

"RESUMELe gisement Silidor représente la dernière découverte effectuée dans le camp minier de Rouyn-noranda (fin 1985). Située à 5 km à I' ouest-nord-ouest de Rouyn-Noranda, ce gisement aurifère doit être mis en exploitation au cours du mois d’avril 1990. 11 est constitué par plusieurs facies minéralises comprenant une tonalité, un dyke mafique, une brèche carbonatée et par une veine de quartz. L’or se présente en particules très fines associées ou non à la pyrite. La zone d’altération hematitisee se développe sur une largeur de 30m environ de chaque cote de la veine. Une première étude structurale montre que la minéralisation s’est mise en place le long d’une zone de tension, orientée NNW, résultant de I' interaction de deux zones de cisaillement dextre orientées N270° et N300°. Les réserves diluées sont évaluées jusqu’ à 700 m de profondeur, à 4,78 Mt à 5,4 g/t Au. ABSTRACTThe Silidor ore deposit, located 5km WNW of Rouyn-Noranda, is the latest discovery made in the Rouyn-Noranda mining camp. Discovered at the end of 1985, this gold deposit will begin production in the spring of 1990. The deposit comprises several facies including a tonalite, a mafic dyke, a carbonated breccia and quartz vein. Gold is present as very fine grains, associated or not with pyrite. A 30m wide hematized alteration zone is developed on both sides of the structure. A structural analysis shows that the mineralization took place along a NNW oriented tension zone that resulted from the interaction of two dextral shear zones, oriented N270 and N300 respectively. The diluted ore reserves are estimated at4,78 Mt at 5,4 g/t down to a depth of 700m."

Jan 1, 1990

By D P. Blair

Rio Tinto’s Hope Downs Operations are currently mining iron ore in their South Central Pit. Prior to the commencement of mine operations, Hope Downs carried out an extensive archaeological investigation and identified an ancient rock shelter lying within the proposed mine boundaries. The site is significant to the traditional owners/custodians of the land in this part of the Pilbara, and thus the final pit design was changed to preserve the rock shelter, which now lies 30 m outside the mine boundary. In order to further preserve this ancient dwelling from blast-induced damage, blast design procedures were improved over time to minimise the vibration impact when blasting close to the shelter. Blasting and vibration monitoring commenced in May 2008 using pyrotechnic delay sequences and normal-direction firing. In October 2009 electronic delays were used to reverse-fire blasts close to the shelter in order to create a damage zone between the initiating holes and the rock shelter. A detailed statistical analysis of the vibration data shows a reduction in the higher levels of vibration for blasts fired after October 2009, which is most likely caused by the created damage zone. In May 2010, a site-specific vibration model was developed and implemented, and based on Monte Carlo waveform superposition. This model was used to give a further insight and improvement to the blast delay sequences when blasting close to the shelter. However, such models are expensive to implement and have limitations, which reduces their potential for estimating the probability of getting an excessive vibration due to a given blast design. In this regard, it is more realistic and significantly less expensive to use a recently developed probabilistic analysis based on simple charge weight scaling. This analysis shows that there was a higher probability of exceeding prescribed vibration limits at the rock shelter for blasts fired before October 2009 than there was for blasts fired after October 2009.

Nov 8, 2011

By M Kim, J Park, I-K Suh, E Kim, J Lee

One of the key technologies in developing hydrogen-enriched ironmaking operations is the control of the carburisation, melting, and dripping behaviour of the iron ore burden materials. When a hot compacted iron (HCI) is charged in the blast furnace or the FINEX Melter-Gasifier, iron oxide reduction, the reduced iron’s carburisation, and the melting of iron and slag occur successively. This study investigated the reduction, carburisation, melting and dripping behaviour of HCI under a COH2 gas mixture using the high-temperature X-ray radiographic technique. Under 100 per cent CO gas atmosphere, the dripping temperature was 1410°C. When 5 per cent H2 was introduced, the dripping temperature slightly decreased to 1400°C. Furthermore, the dripping temperature gradually increased as the H2 gas composition increased. As 30 per cent H2 was introduced, the dripping temperature reached 1414°C. The carbon concentration in the drained metal samples gradually increased with increasing H2 composition. It is considered that H2 decreased FeO content in the slag, yielding the increased melting temperature and viscosity of the slag. On the other hand, H2 accelerated the carburisation of the reduced iron by CO gas, enabling the homogenisation of the oxide materials to form a liquid phase. Therefore, it is considered that introducing H2 in the reactor is helpful to increase productivity and energy efficiency by accelerating the liquid phase’s formation.

Aug 21, 2024

By William P. Blake

In directing attention to the newly-opened zinc-ore region in Southwestern New Mexico, I adopt a suggestion made at the Engi neering Congress last summer in Chicago by Prof. Le Neve Foster, who commended the indication of the geographical position of a district under description by means of an outline-map. Such a map is the more important in this instance, inasmuch as the region to be described is remote and little known even in the United States. Until within a few years it has been infested by the savage Apaches, has not been often visited by mining engineers, and could not be

Jan 1, 1895

By Wallace W. Roepke

The Bureau of Mines studied the cutting characteristics of point-attack bits to reduce airborne respirable dust and energy during cutting. Linear cutting of two coal types using four bit types at three depths of cut with three space-depth ratios was performed with a modified horizontal milling machine using an optical particle-size monitor for respirable dust sampling. The cutting action of one bit on a rotary hardhead mining machine was mathematically analyzed and compared with the results of the linear cutting test. Airborne respirable dust per unit mass cut (specific dust) was found to be a monotonically increasing function of specific energy. Specific dust and energy decrease with increasing depth of cut. The amount of nonairborne respirable dust was 100 to 1,000 times greater than the airborne dust. The plumb-bob bit produced the most airborne respirable dust and the highest specific energy of the four bits tested. Rotary cutting was a greater dust producer and energy consumer than linear cutting because of the constantly changing depth of cut, space-depth ratio, and attack angle of the bit relative to the horizontal bedding planes. A new cutting technique is proposed to minimize the existing problems of the rotary cutting machines by providing greater production, reduced dust, and minimized methane ignition potential at the face.

Jan 1, 1976

By T. P. Meloy

Current coal cleaning technology uses heavy media (HM) for the recovery of coal in particles larger than 1/16 of an inch. Through the use of float sink measurements of the feed and products to commercial HM unit operations, a selection function, sometimes called Tromp curve in the coal industry, can be computed. Since the selection function is a plot f the probability of a particle appearing in the float versus the particle density, the slope of the curve will be sharper at the point where the particle has a 50% chance f appearing in the float. Thus, the separation will be better. Fine-tuning a unit operation or a circuit of unit operations requires that the selection function be accurately known. By current practice, it is difficult to obtain an accurate measure of the slope because, when the selection function is plotted versus density, the data forms an S-shaped curve which lacks data points near the 505 point of the curve. This lack of sensitivity in measuring the slope means that small recovery improvements cannot be detected; thus, only large improvements are measurable. Since most engineering improvements are small when individually considered, but large when aggregated ever many small improvements, this lack of measurement sensitivity rules out the slew march toward improved efficiency. This paper presents a method of analyzing heavy media selection functions resulting in a far more effective measure of the selective function slope. Furthermore, this improved method is applied to a number of industrial coal cleaning plants for both heavy media and heavy media cyclones. Using the work of Hudy (1968), and Deurbrouck and Hudy (1972), selection functions for individual unit operations in each plant are calculated as a function f particle size as well as density.

Jan 1, 1982

By Francis A. Thomson

DO the curricula of our mineral technology schools prepare their graduates to meet properly the full range of their responsibilities in after life? An unequivocal "no" could be returned to this question, because training and experience in professional work are quite as important as adequate college preparation. Furthermore, a had curriculum with a splendid corps of men doing the teaching and a competent body of students doing the learning will produce a better result than an ideal curriculum in the hands of unqualified teachers and poorly prepared students.

Jan 1, 1937

By J. P. Bennett

Based on previous Bureau of Mines research indicating that improved high-temperature properties could be achieved for periclase refractories through chemical additions, the Bureau investigated the properties of full-size bricks produced from chemically modified periclase refractory grains and the suitability of making such chemical additions to Mg(OH)2 slurries prior to production of the periclase grains. In full-size brick testing, strength values, both hot and cold, for the optimized bricks were superior to those for a commercial 98-wt-pct-MgO refractory. The best results were obtained for a natural magnesite with an adjusted CaO:Si02 (C:S) ratio of 3.0 and a 1.0-wt-pct addition of Zr02 and for a seawater periclase with an adjusted C:S ratio of 2.5 and a 0.5-wt-pct addition of Mn02. For samples produced from chemically modified Mg(OH)2 slurries, additions of both Mn02 and Zr02 and an increase in C:S ratios produced significant increases in hot flexural strength, similar to those resulting from chemical additions made to periclase grains. The most effective modifications were additions of Mn02 to brine-derived periclases having a C:S ratio adjusted to 3.0. These results on chemically modified magnesia refractories indicate that such material could potentially substitute for magnesiachrome refractories containing imported chromite.

Jan 1, 1984

By D. Tetsuka, H. Okamoto

The amount of impurities to be processed in a copper smelting process has increased for recent years because of an increase in the electronic scrap amount. It has been found that Sb and Ni effect on the operation of our copper electrorefining process. It is found that the current efficiency of the copper electrorefining tended to be decreased as the Ni concentration in the electrolyte increased. The passivation of the process seemed to be more related to SO4 concentration in the electrolyte rather than the Ni concentration in it. The current efficiency decreased when the Sb content in the anode was high. A high Sb content in the anode caused easy passivation by forming a gel-like film in the slime layer. We have developed a method to for see the anode passivation in a short time while generating a slime layer. We confirmed the tendency of passivation through the experiment of changing Pb content in anode. Passivation was easily occur with an increase in Pb content in the anode. The amount of slime increased as the Pb content in the anode increased. This suggests that passivation was facilitated because liquid diffusion near the anode was inhibited. INTRODUCTION The amount of impurities to be processed in copper smelting has been growing in recent years because the amount of electronic scrap has increased. Figure 1 shows that the contents of Sb and Ni in copper anodes have increased since 2007.High Sb and Ni contents in the copper anode decreased the current efficiency of the process and made the quality of copper cathode poor because of the anode passivation and the formation of floating slime in the electrolyte during electrorefining. If these influences of impurities are suppressed, it would be possible to make copper electro-refining current density higher and to process much amount of electronic scrap. We examined the components of our copper electro-refining process like anode composition, slime properties and electrolyte composition, and investigated the mechanism by which Sb and Ni affect passivation and current efficiency. When examining the influence of Ni, we noticed that the SO4 important. The effect of SO42 – was also discussed

Jan 1, 2019

By Nadir Ansari, Brian W. Wilson, Marina S. W. Li

"A hybrid shoring system consisting of cast-in-place soldier piles with Cutter Soil Mixing (CSM) infill panels was constructed for temporary support of a 19.8 m (65 ft) deep excavation in Vancouver, British Columbia, Canada. Deep Mixing (DM) was completed up to 9.7 m (32 ft) in fill, peat, wood waste and clayey silt with embedment in dense till, and soldier piles constructed through the dense till extending to below final excavation level. Two trial CSM panels were installed ahead of production to assist with developing the termination criteria of the CSM panels in the dense till. The constructed depth of the CSM panels was based on interpretation of real-time monitoring data obtained through the Bauer B-tronic system. Inclinometer monitoring data from two CSM panels and two soldier piles, as well as soldier pile survey target data was used to assess and monitor the performance of the hybrid shoring system throughout bulk excavation. The objectives of this paper are to provide an overview of the design and construction aspects of the hybrid DM shoring system and to present inclinometer and pile target data to demonstrate the lateral performance of the CSM infill panels and soldier piles. This paper also discusses the merits of using real-time monitoring data as part of the engineering decision-making process for validating CSM panel construction. BACKGROUND A hybrid DM shoring design was recently completed for a high-rise development in downtown Vancouver, British Columbia for temporary support of a five level basement excavation. Deep mixing was proposed by the excavation and shoring design-build team as the preferred method to construct infill panels between soldier piles because of the speed at which the shoring system could be constructed in variable fill, peat, wood waste and overburden compared with traditional secant piling methods. The development site is generally a truncated triangle in plan, with the longest side of the triangle being approximately 115.7 m (380 ft) long and the two shorter sides being approximately 71.6 m (235 ft) (Hybrid Shoring Wall 1) to 75.0 m (246 ft) (Hybrid Shoring Wall 2) long. The site is bounded by an existing bridge off-ramp structure along its longest side, and by city streets on the other two sides, as shown in Figure 1. The truncated section is approximately 16.8 m (55 ft) (Hybrid Shoring Wall 3) long. Due to project constraints, the hybrid DM and soldier pile shoring system was only proposed for the two shorter sides of the triangle and the truncated section. Traditional secant piles were installed for the longest side. This paper focusses on the hybrid shoring system. A typical detail showing the CSM infill panel with the soldier piles is presented in Figure 2."

Jan 1, 2017

By Alessandro Navarra, Roberto Parra, Boyd Davis, Frank Mucciardi

A smelter scheduling algorithm has been developed, which allocates the oxygen production between the smelting furnace and the converter aisle, so as to maximize copper throughput. The algorithm is intended for daily operation planning, controlling the sequencing of the converter cycles, and the oxygen drawn by these cycles. In some cases, it may be worthwhile to decrease converter oxygen allocation in favour of the smelting furnaces. Thus, a better utilization of the oxygen plant can increase primary copper throughput by several percentage points. This principle is demonstrated through sample computations. The approach presented in this paper can be incorporated into smelter management software.

Jan 1, 2015

By A. G. Roach

Introduction This paper deals with the operations and plant of the Craigmont Corundum Project, formerly of Wartime Metals Corporation but now under the Mines Section of the Resources Development Branch of the Department of Reconstruction and Supply. Corundum is recovered by the re-treatment of an old tailing deposit at Craigmont, Ontario. Crude concentrates so produced are shipped to the plant of the American Abrasives Company, Inc., at Westfield, Mass., for final processing and distribution to the abrasive industry. The plant was recently described in a paper entitled Craigmont Corundum which was presented by the writer before the Chicago meeting of the A.I .M.E. in February, 1946. General The Project is located on? lots 4 and 5, concession XVIII, township of Raglan, Renfrew county, Ontario, near the village of Combermere, which is on Highway 62. The property is about 135 miles from Ottawa. The general area enjoys a pleasant climate with moderate summer temperatures, though the winters are rather severe, the mercury frequently falling to - 35 deg. F. The excellent boating, fishing, and hunting have made the district a favourite resort for tourists. Lumbering is the main industry. Some farming is carried on, but the soil is poor and much of the land is hilly and rocky. There are no other operating mines in the immediate vicinity, though several 'industrial minerals', including mica, feldspar, nepheline, beryl, socialite, and others have been produced in the area. The district is drained by the York and Madawaska rivers and is generously dotted with large and small lakes. The general elevation is about 1,000 feet above sea level, though numerous hills rising several hundred feet give a rolling appearance to the landscape.

Jan 1, 1946

By Robert W. McKibbin

The Bureau of Mines conducted laboratory tests to determine the slurry transport and deposition properties of coal waste. A 188.5-ft pipe test loop was constructed with instruments to measure density, flow, and power and discharge, suction, and differential pressures. A 20-ton ample of Western coal waste was crushed and screened to 100 pct minus 1/2 in. Eight loop tests using this graded waste were run at slurry densities ranging from 1.15 (25 wt-pct solids) to 1.46 (60 wt-pct sol-ids) 0 The resultant friction-'pressure gradients ranged from 0,06 to 0.24 ft of water per foot of 4-in standard steel pipe. Particle-size degradation was significant.. In a typical loop test lasting 25 min, the minus 200-mesh fraction increased from 19 pct to 34 pct. Deposition tests showed that without the use of a flocculant, the slurries would not dewater when left to stand for 1 week. With flocculant, additional water was releas2d; however, the settled slurries remained thixotropic. Further testing is necessary to determine their suitability for use as backfill material in active mines.

Jan 1, 1983

By Songgen He, Jianchun Guo

With the development of complex, unconventional and deep reservoirs, it shows that many rocks behave plastically with the influence of clay and confining pressure. Traditional linear elastic hydraulic fracturing initiation models are not good predictors for elastic-plastic reservoirs. With the deformation theory of plasticity, a power hardening constitutive equation was developed in piecewise approximation method. Based on the nonlinear constitutive equation, a model of the stress field around the wellbore was developed considering fracturing fluid penetrating effect and in-situ stress anisotropy. At last, coupled with the maximum tensile strength criterion and Mohr-Coulomb criterion, a new elastic-plastic hydraulic fracturing initiation model was built. The following conclusions were summarized in the paper: (1)The piecewise power hardening constitutive equation based on the deformation theory of plasticity can accurately describe the nonlinearity of elastic-plastic deformation. (2)Whether the rock is yielded or not is determined by in-situ stress, yield stress, Biot coefficient and pore pressure. (3)Plastic yield has little influence on radial stress but significant impact on circumferential stress. The radius of the plastic zone is positively correlated with in-situ stress but negatively correlated with yield stress, power hardening index, pore pressure and Biot coefficient. (4)Initiation modes include tensile failure and shear failure when rock is yielded. (5) For elastic-plastic reservoir, the initiation pressure predicted by linear elastic model is much lower if the rock is yielded.

Jan 1, 2015

By Don Painter, Nico Sutmoller, Lori M. K. Kahikina, Brian Dorwart

This paper will address the feasibility of using low-density cellular concrete (LDCC) for an annular fill application where project conditions required pumping the LDCC material for distances of up to 16,000 feet. These conditions occurred during construction of the Kaneohe-Kailua Sewer Tunnel in Oahu, Hawaii, between 2014 and 2018. Located on the island of Oahu, Hawaii, this 13-foot-diameter rock tunnel extends for approximately three miles from the Kaneohe Pre-Treatment Facility to the Kailua Regional Wastewater Treatment Plant. The tunnel was built to convey wastewater and provide temporary storage for peak wet weather flows entering the collection system, thereby reducing the potential for uncontrolled discharges. LDCC was chosen for this project partly due to its environmental benefits, which were essential for an application contiguous to the inland marine and coastal waters of the Pacific Ocean. In order to ensure optimal performance characteristics—compressive strength (with a requirement of 300 psi at 56 days), flowability, and light weight—were achieved, extensive testing of various LDCC products and mix designs was completed. The testing measured the initial set time of the LDCC as well as the compressive strength needed to reduce the quantity of grout lifts required for the project.

Jun 13, 2021