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By Alessandro Bertero, Dylan Pearson, Wesley Schmutzler, Matteo Bertoni

"The SR 83/US 331 highway is located in the Florida panhandle, where it connects the Walton County beaches to the I-10 corridor. The roadway is of vital importance to the economy of the area as well as its safety since it represents the primary hurricane evacuation route from southern Walton County. The Florida Department of Transportation (FDOT) decided to increase the number of traffic lanes from two to four and improve the geotechnical properties of the moderately deep, very loose foundation soils, that had affected the highway rideability for years. The soil mixing was selected as the method to meet the unique deep ground improvement challenges of the project. The design required that Shallow Mixing Method (SMM) be used to build a 10-foot thick platform that transferred axial load to the bottom soil layers through a series of Deep Mixing Method (DMM) columns. Upon completion over 8,300 SMM columns and 1,500 DMM columns had been installed, with no remedial work required. Also, only 1% of the almost 1,500 specimens tested did not meet the specification requirements. This paper will describe the challenges encountered and provide valuable information that may be useful for other future projects, including details not previously published.INTRODUCTIONThe counties of Walton and Okaloosa have been a very popular vacation destination for many ears. The 50-mile long coastline boasts beautiful, sugar-white beaches and waters the color of emeralds. The popularity of the area has been growing even further, over the last few years. A consequence of this phenomenon is a fast-paced increase of the traffic flow on the SR83/US331 highway, especially at the bridge that connects the Walton County beaches across Choctawhatchee Bay (Fig. 1) to the heavily traveled I-10 corridor. The highway plays a very important role for the area also as a commercial link and as the primary hurricane evacuation route from southern Walton County. The increase in traffic has produced higher travel time, when not a complete traffic paralysis, and exacerbated the issue of ground settlement where accelerated wearing of road foundation occurred due to the presence of very loose, moderately deep, soils, that had afflicted the highway for several years. The Florida Department of Transportation (FDOT) decided to put an end to these issues by increasing the number of traffic lanes from two to four and improving the geotechnical properties of the foundation soils. The Design-Build Maximum Price Request for Proposal (RFP) issued for the expansion of the Choctawhatchee Bay Bridge saw the participation of numerous D/B teams which produced various technical solutions. Among them, the FDOT selected the Skanska/Parsons Brinckerhoff (General Contractor) proposal which provided for the use of soil mixing as the ground improvement technology. The design/build team assigned Foundation & Geotechnical Engineering (Designer of Record) the ground improvement design which Treviicos South (Specialty Contractor) would execute."

Jan 1, 2017

By Jilai Xue

Industrial wastes containing 30-50 wt.% Al2O3 and 40-60 wt.% SiO2 may serve as an alternative resource for producing Al-Si alloys. Various raw materials such as used refractory materials from metallurgical furnaces, coal fly ash, andalusite residues, and so on were tested in laboratory to produce Al-Si alloys using carbon-thermal reduction process. A mixture of anthracite and petroleum coke was used as reducing agent. One of the most important operations was to prepare the briquettes made of different raw materials with varying contents of Al2O3 and SiO2. The effects of briquette property, A/S ratio (mass ratio of Al2O3 and SiO2), the amount of carbon reducing agent, on the reduction process and the resulting metals were investigated. The results are useful for development of an alternative technology for Al-Si alloy production, which has the potential application in recycling metals from industrial wastes containing Al2O3 and SiO2.

Jan 1, 2010

By G. L. Oldright, J. D. Sullivan, W. E. Keck

"An apparatus and procedure developed in the laboratory of the South-west Experiment Station of the Bureau of Mines are capable not only of determining the rate and volume of penetration of solutions into porous materials but also of determining the total volume of voids within particles of porous material, and the density. The method is applicable to ores, bricks, concretes, tiles, filter bottoms, or other porous materials of this nature. As will be made clear in the descriptive matter to follow, the method measures (a) the volume of voids within the porous materials and is not concerned with the interstitial space between the particles.Porous materials usually contain some large voids and also pores that are capillary in nature. To measure the total volume of voids in a sample it is necessary to replace the gas or gases within the voids with some liquid of known density. The large cavities can be filled quite readily, but under ordinary conditions a long time may be required to fill capillary pores. As many porous materials are of a decomposable nature it is necessary to evacuate the porous materials and then submerge them in a liquid of known density to bring about saturation in a short time. Then by the use of a hydrostatic balance the volume of porous material (solid itself) can be determined. To determine the volume of porous material plus voids it is necessary to coat the sample with some material, such s paraffin, which will prevent solution from entering the voids; then, by means of a hydrostatic balance, the volume of porous material plus voids is determined and by subtracting that of the porous material from this the volume of voids is ascertained. The rate of penetration of solutions can be determined either (a) by measuring the change in weight as the sample becomes saturated when immersed ni a liquid of know density, or (b) by measuring the volume of liquid penetrating with a dilatometer. In either instance, due to the fact that some penetration takes place as soon as the sample comes in contact with solution and before a reading can be taken, the sample must be paraffined to determine the total volume of penetration. Since many porous materials partly decompose and disintegrate in liquids the rate and volume of penetration can better be measured by dilatometer than by the change in weight, as saturation takes place when immersed in a liquid. The details of procedure for determining (a) total volume of voids, and (b) rate and volume of penetration are given in this paper."

Oct 1, 1930

By Robin B. Dill, Mark Pelletier, Daniel J. Dobbels, Subodh Bhaumik, Daniel J. VanRoosendaal

Although primarily cut-and-cover excavations are required for replacement of the existing elevated I-93 interstate highway through the heart of Boston for the Central Artery/Tunnel (CA/T) project, some mined tunnel construction was also undertaken. The mined tunneling conducted was the 22-m-wide northbound roadway structure which passed below a 20-m-deep operating underground subway station that was built in 1913. The innovative underpinning scheme used to support the subway station during construction resulted in the successful mining beneath the subway station with negligible vertical settlement. Two grouting galleries were carefully mined below the subway structure, and pre-grouting of the granulary, pervious glacial soils and weathered bedrock was carried out from these galleries. The reinforced concrete walls of the underpinning structure were constructed within three stacked drifts that were sequentially mined below each grouting gallery. After 11 cross adits were mined between the grouting galleries, cast-in-place post-tensioned girders that spanned between the stacked-drift walls were constructed to support the subway station. The stacked-drift walls also provided lateral support for the 22-m wide by 29-m long by13-m high opening beneath the girders.

Jan 1, 2001

By G. L. Oldright

The Metallurgical Branch of the Bureau of Mines, as a part of its duties under the Organic Act, works to prevent wastes in industry and to disuse inmate information on the fundamentals of metallurgical processes. During the war, the necessity of large production was increasingly emphasized. Such duties necessitate from time to time the study of units of full commercial size, the operation of which is beyond the facilities of the Branch. When developments have reached this stage; work has been continued in cooperative agreements with operating companies that have been willing to contribute the use of their plants and staffs and to allow the publication of the results obtained for the common good of the industry.

Jan 1, 1948

By K. W. Lee, C. Pound, J. Carmody, L. Petersen, C. Nelson, J. G. Cai

The feasibility of developing the Underground Science City below the Kent Ridge Park has been investigated. The primary aim of the study has been to explore the possibility of creating underground space to house a new community of research laboratories and offices. The investigation represents the first such study undertaken in Singapore for a non-military underground facility. The paper describes the geology of the Underground Science City site and illustrates the layout and plan of the Underground Science City. The geology and rock mass below the Kent Ridge Park is generally favorable for the development of an underground cavern complex. Underground Science City can be potentially developed housed in a cavern complex. Several potential development schemes are studied; with various combination of deep/shallow mined caverns of different span sizes and access options. The preferred scheme is shallow, mined room-and-pillar caverns with large spans and shaft accesses at both existing surface Science Park 1 and Science Park 2. The scheme can be potentially expanded laterally to create more underground space for new Underground Science Cities at Kent Ridge area.

Jan 1, 2001

THE Broken Hill mining field, approximately 31 miles in length, is at present being exploited by seven companies, viz. : North Broken Hill Limited, Junction North Broken Hill No Liability, Broken Hill Proprietary Block 14 Company, Broken Hill ProprietaryCompany Limited, Sulphide Corporation Limited, Broken Hill South Limited, and Zinc Corporation Limited.The variation in size and shape of the ore-bodies in the mines of these companies, together with the many alterations in pitch and dip, necessitates differences in methods of mining, each company working out its problem in its own particular way.In the matter of chute construction for the handling of the ore broken in the stopes, each mine belonging to the above companies has adopted a style particularly its own, though it may be said that one or two of the types approximate very closely to each other, slight minor differences only being noticed in the design. It is the purpose of this paper to give a brief description of the principal types of chutes now in use in th,e various mines on the field, and in doing so they may roughly be classified into three groups, viz:1. Bulk Chutes, 2. Circular Chutes, 3. Square-set Chutes.The Bulk type of chute is used in the North and British mines of the North Broken Hill Limited, the Central and Junction mines of the Sulphide Corporation, the South Blocks mine of the Zinc Corporation, and the Block 14 mine.The Circular type of chute is used by the Broken Hill South mine and the South Blocks mine.The Square-set chute is used in the Proprietary mine, the Junction North mine, and occasionally in other mines where the square set method of mining is a necessity, and more particularly as mullock passes.

Jan 1, 1925

By Madgwick J. C

Powders prepared from the algae Gracilaria secundata, Ulva lactuca and Ecklonia radiatawere shown to provide sole nutritional support for microbial, microaerobic, biodegradation of low-grade manganese dioxide ore. G. secundata was the most effective bacterial nutrient giving 32 per cent recovery of Mn++, at an average rate of 63 mg Mn++/litre/day and a yield of 24 mg Mn++/g dry powder in microaerobic cultures containing 1.5 per cent (w/v)MnOz ore and 3per cent (w/v) powder over 14 days. Although G. secundata was approximately half as effective as molasses in supporting microbial decomposition ofMnOz, possible on-site growth ofthe alga could be economicaIIy more practical than transporting carbohydrate to a distant mine site.

Jan 1, 1987

By Philip Weaver

The MIDAS project is funded by the European Commission (DG Research) and began on the 1st November 2013. The project will investigate the environmental impact of deep-sea mineral and energy extraction: specifically, polymetallic sulphides, manganese nodules, cobalt-rich ferromanganese crusts and the potential mining of rare earth elements. As deep-sea mining becomes ever closer, and the International Seabed Authority begins to develop its regulatory framework for exploitation of deep-sea minerals, MIDAS is well timed to provide fundamental scientific information. The MIDAS partnership represents a unique combination of scientists, industry, social scientists, legal experts, nongovernmental organisations and small and medium enterprises. MIDAS is carrying out research into the nature and scales of the potential impacts of mining including 1) physical disturbance of the seabed by mining, the creation of mine tailings; 2) the potential effects of particle-laden plumes in the water column, and 3) the possible toxic chemicals that might be released by the mining process. Key biological unknowns, such as connectivity between populations, impacts of the loss of biological diversity on ecosystem functioning, and how quickly the ecosystems will recover will all be addressed. The plan is to use this information to aid development of recommendations for best practice in the mining industry. A key component is the involvement of industry within the project and through stakeholder engagements to find feasible solutions. The project will work closely with European and international regulatory organisations to take these recommendations forward into legislation. A major element of MIDAS will be to develop methods and technologies for 1) preparing baseline assessments of biodiversity, and 2) monitoring activities remotely in the deep sea during and after exploitation, including ecosystem recovery. To carry out this work MIDAS is conducting a number of research cruises to examine the above issues at potential sites for exploitation of SMS and nodule deposits. This talk will present some of the recent findings of the project.

Sep 1, 2014

By Wilfrid Comeau

This paper deals with the concept of a Quality-Assurance Manual, to the ISO-9001 Level, for quarry blasting in the urban environment. A case history of the incident, which led to its development, is presented in addition to three other case histories. These case histories are related to the potential effectiveness of a well thought-out and applied Quality-Assurance Manual in the conclusions. The basic principle, behind the development of a Q-A manual, is to supply a maximum of quality assurance with a minimum of disturbance to the operation of the quarry. This requires that every intervener in the quarry blasting operations, from management to labourer, be made responsible for the quality of their work. This basic goal can be achieved with a minimum of paper work and added bureaucracy. The manual respects the ISO principle that: Q-A Manuals are not recipe books and should allow for continuing technological developments.

Jan 1, 2003

By Navid Hosseini

Several empirical equations to estimate coal pillar strength have been presented in academic studies. The development processes of these equations are similar and are usually obtained by fitting the mathematical function (curve) to field data. One of the best criteria to evaluate the quality of fitting for such equations is the correlation coefficient R2, which has limited applicability. It is necessary to calculate the correlation coefficient access to the initial data for which the equation is presented; this is impossible for many coal pillar strength formulas. This paper presents a new approach based on the analysis of uncertainty amplitude to compare the coal pillar strength. This approach utilizes a combination of parameters such as Mean Squared Error (MSE), Root Mean Squared Error (RMSE), function type and degrees of freedom. The confidence level of constants is subsequently formed and the correlation coefficient becomes more comprehensive. Therefore, for an effective comparison, the efficiency and accuracy of coal pillar strength formula can be used. Keywords: Coal Pillar Strength, Correlation Coefficient, MATLAB, Uncertainty Criterion

Jan 1, 2012

By Emmanuel Henry

Few industries are more challenged by technical, political and market uncertainty than the mineral industry. Technical uncertainty in mining projects concerns the volume and quality of the resource, the processing and metallurgical parameters, the production efficiency, etc. Political uncertainty can take diverse forms and includes possibilities of change in the taxation system, risk of expropriation and risk of social instability or war. Market uncertainty depends on the market structure of the commodity; price and demand volatilities are the most common sources of market uncertainty. Intensive feasibility studies including these uncertainties and risks are required before investing up to billions of dollars in the development of a new mine. Current feasibility studies are often based on a single (or very few) mean geological scenario and simplified price profiles along the life of the project. Yet, strategic decisions, for example, the level of investment in exploration and metallurgical studies, adoption of a flexible, but more costly, mine design and risk-sharing strategies are made at an early stage. Over the last twenty years, Real Option theory has emerged as a unifying framework enabling strategic planning under uncertainty (technical, political and market). Geological and market variances (second order statistics) are pivotal for proper uncertainty quantification. The present study explores the possible benefits of combining modern geostatistical tools and financial techniques for project management. More precisely, the following questions are examined: Is geological uncertainty really an issue? Can we combine geological and price uncertainties in a unifying Real Option framework? A simple example aimed at illustrating the concepts involved is presented.

May 1, 2003

By J. Coffin, R. Multani, C. Deredin

Glencore’s Strathcona Mill has recently evaluated a pyrrhotite depressant combination of diethylenetriamine (DETA) and sodium metabisulfite (SMBS) to improve its overall plant pyrrhotite- pentlandite (Po-Pn) selectivity, with the aim of producing a higher quality nickel concentrate. In a previous paper, key findings from a comprehensive lab-scale program (completed at the XPS Centre) were summarized where, of the depressants tested, DETA/SMBS combination was found to be the most effective in improving the Po-Pn selectivity. The present paper describes the metallurgical program recently completed at Strathcona Mill; DETA/SMBS evaluation on select plant “grab” samples as well as the major results of three DETA/SMBS plant trials conducted on several plant ore feeds (long-term testing). Interestingly, it was found that there was variable success in using DETA/SMBS depressants on the different plant ore feeds; DETA/SMBS (dosage: 25/50 g/t milled feed) on lower Cu feeds demonstrated a ~2% Ni recovery increase at the same Ni grade. On the other hand, higher Cu feeds demonstrated virtually no benefit from DETA/SMBS at the same plant dosage, suggesting that higher DETA/SMBS dosage (at specific locations) than that tested is required to overcome the increased Cu-DETA complexation for these particular feeds. Glencore Nickel – Sudbury Integrated Nickel Operations owns and operates Strathcona Mill which has been processing Ni-Cu ores from the Sudbury Basin since 1968. The valuable sulfides are pentlandite (Pn) – (Ni,Fe)9S8 and chalcopyrite (Cp) – CuFeS2, majority of the sulfide gangue is pyrrhotite (Po) – Fe(1-x)S [0 < x ≤ 0.125] which is present in two forms: hexagonal Po (Fe9S10) and monoclinic Po (Fe7S8) (Multani & Waters, 2017; Lawson et al., 2014). Currently Strathcona Mill processes ore mined from two primary sources from the Sudbury area and produces two concentrate streams: (1) nickel-copper concentrate that is sent to the Sudbury Smelter; and (2) copper concentrate that is shipped to the Fonderie Horne (Glencore Copper, Rouyn-Noranda).

Jan 1, 2019

By Tuncel M. Yegulalp, Anuta Belova

This paper expands on the ZECA (Zero Emission Coal Alliance) technology, which is aimed at making coal a sustainable source of clean energy in the near future. The technology proposed immediate capture of carbon dioxide and other pollutants upon generation, thus alleviating their negative effects in the Earth’s atmosphere. ZECA proposes using chemical energy of coal to produce hydrogen; the latter is then used to produce electricity via fuel cells or Hyrogen-Oxygen turbines. In this study, a chemical engineering package, AspenPlus 12.1, is used to simulate the reactor (reformer) in which hydrogen is produced from methane water and lime as part of the zero emission power plant. Thermodynamic conditions, pressure and temperature, are optimized with respect to molar hydrogen production. Under the proposed conditions, molar conversion efficiency, carbon to hydrogen, of 95% is achieved. Further studies are required to model the complete power plant and to optimize it for efficiency.

Jan 1, 2005

By Ernest Baafi

A simulation model RoadSIM using the ARENA modelling system has been developed to evaluate roadway development options for a given development panel configuration. The RoadSIM simulation system has provisions for variability/randomness in operations including cutting and loading at the face, tramming and discharge of coal to the boot end and availability of equipment. The modelling system provides a means for assessing the operational limitations of roadway development practices at a particular coalmine. It is a ?what if? tool that allows a range of equipment, configurations and operating practices to be assessed in terms of achievable advance rates and equipment utilisation. Output from the system is in the form of a dynamic visualisation as well as summary reports and detailed logs of operations over time.

Oct 1, 2009

By Anthony T. Xannacchione, Luis E. Vallejo

At present, there is little knowledge concerning the shear strength of clays containing floating rock particles with concentrations from 0 to 30%. In practice, the effect of rock particles is typically disregarded in shear strength analysis The two primary reasons for this are: 1) a lack of agreement concerning the influence of rock particles on material strength, and 2) the expense and difficulty of testing day-rack mixtures with existing laboratory procedures. These factors have impeded the development of successful slope remediation design techniques far colluviums derived from resistant sedimentary rocks or spoil produced from surface mining. This study reviewed 3 1 technical papers which contain analysis of shear strengths for clay and sands with varying mixtures of rock particles. These technical papers, published over the last 40 years, are comprised of field case studies, laboratory evaluations, and theoretical analysis. Evaluation of this body of knowledge ha shown that the shear strength gradually increases with increasing percentages of floating particles in unsaturated clays.

By Joseph T. Coe, Siavash Mahvelati, Alireza Kordjazi

This paper introduces recent advances in stress-wave NDT systems for use in assessments of in-service foundation integrity and drilled shaft construction. The primary results of the laboratory experiments are very promising, as the acquired image was capable of differentiating changes in pile cross section as low as 0.3 cm. The preliminary results with the same hardware components on a relatively large scale cemented sand model were also promising. A brief overview is provided of both systems including hardware, survey methods, and data processing techniques, followed by a discussion on application of the results to QA/QC of deep foundations. INTRODUCTION There are two main applications in which current QA/QC NDT technology fails to provide sufficient information regarding deep foundation conditions: (1) detection of flaws in outside cover concrete of drilled shafts and corrosion in steel piling; and (2) evaluation of anomalies beneath the bottom of drilled shaft excavations. Previous studies have demonstrated the capabilities of high frequency stress waves for geotechnical and foundation evaluation purposes (Lee and Santamarina 2005; Coe and Brandenberg 2010; Coe and Brandenberg 2012; Coe and Kermani 2016). Higher frequency waves can visualize smaller anomalous features at the expense of higher attenuation and smaller propagation distance. Therefore, the goal of this study was to advance the state of NDT practice by development of a prototype high resolution stress-wave imaging system as proof-of-concept. The equipment and hardware were modular, which allowed simultaneous development of two system configurations for application to in- service foundations as well as drilled shaft excavations during construction. Results are presented based on two large scale soil models. The first laboratory model simulated section loss in an in-service steel pipe pile and drilled shaft foundation (Fig. 1a). The second model simulated anomalous conditions beneath drilled shafts excavations as might be encountered in areas with significant karst (Fig. 1b). For both models, evaluation of foundation conditions relied on the propagation of small amplitude seismic stress waves using hardware similar to those described in Coe and Brandenberg (2010) and Coe and Brandenberg (2012).

Jan 1, 2018

By Yoshio Nakano

Keywords: Tannin gel, Palladium, Separation, Redox We have developed the novel recovery system of palladium from wastes, which is simple and generates little secondary waste in comparison with the conventional recovery processes, using tannin gel particles synthesized from condensed-tannin molecules. Pd is adsorbed onto the tannin gel particles through inner-sphere redox reaction mechanism: two-electron transfer from tannin gel to Pd(II) species, accompanied by ligand exchange between chloropalladium(II) complexes and tannin molecules. In addition, we propose the separation system of Pd and Au from Pd-Au mixture, which is feasible due to the difference in oxidization and reduction potential between Pd and Au species: PdCl3(H2O)? and PdCl42? are less adsorbable than Pd species containing fewer Cl, such as PdCl2(H2O)2 and PdCl (H2O)3+, while such a distinct difference between Au species is not observed.

Jan 1, 2005

By Robert Martin, Brian W. Stump, David P. Anderson, W Scott Philips

Since 1994, various mines in the US have cooperated with research scientists at the Los Alamos and Lawrence Livermore National Laboratories to address issues related to verification of the Comprehensive Test Ban Treaty (CTBT). The .CTBT requires that no country may conduct any nuclear explosion in the future. While the CTBT is a significant step toward reducing the global nuclear danger, verifying compliance with the treaty requires that the monitoring system be able to detect, locate and identify much larger numbers of smaller amplitude seismic events than had been required previously. Large mining blasts conducted world-wide will be of sufficient amplitude to trigger the monitoring system at the lower threshold. It is therefore imperative that research into the range various blasting practices employed, the relationship of yield to seismic magnitude, and identification of anomalous blasting results be performed. This paper will describe a suite of experiments funded by the Department of Energy and conducted by the Los Alamos and Lawrence Livermore National Laboratories in cooperation with the US mining industry. Observations of cast blasting, underground long wall generated coal bumps, stoping, and explosively induced collapse of room and pillar panels will be presented. Results of these dual use experiments which are of interest to the mining community will be discussed. These include 1) variation of amplitude of seismic energy at various azimuths from cast blasts, 2) identification of the extent of back failure following explosive removal of pillars, and 3) the use of single fired shots for calibration of the monitoring system. The wealth of information and discovery described in this paper is a direct result of mutual cooperation between the US Government and the US Mining Industry.

Jan 1, 1997

By D. Nutakor

Rock joint stiffness is not only a poorly known parameter, but also has no established laboratory measurement procedure. This paper presents methods used to determine the normal and shear stiffnesses of healed joints filled with vapor-altered minerals obtained from the Yucca Mountain site in Nevada. Results show that these joints behave linearly up to 85% of their loading history and are stiff with strengths very close to the strength of the intact rock. Factors that might have contributed to the linear behavior of these joints are discussed and areas requiring further investigation are provided. Joint normal stiffness ranges from 7.16 to 64.77 GPa/mm with an average value of 26.93 GPa/mm, while joint shear stiffness averages 11.41 GPa/mm and ranges from 3.09 to 28.41 GPa/mm. Young?s modulus of the vapor-altered joint infilling was calculated from the stiffness of the healed joint. Young?s modulus of the vapor-altered joint filling material averages 7.89 GPa and ranges from 2.15 to 19.43 GPa. Given the pervasive presence of such altered rock, usually in the form of sub-spheroidal 3-D pockets, this property should be of value in any numerical modeling attempting to describe the mechanical behavior of these tuff formations at the level of detail where inclusions might be a factor.

Jan 1, 2008