Search Documents

By S. Abu-Samra

By virtue of its complex nature, the construction industry comprises a wide spectrum of interrelated variables and factors. This multifaceted character of the construction industry puts the use of engineering modeling tools and techniques on top of project management necessities. This research introduces a macro-level earthmoving management system using Genetic Algorithms (GAs) to reach the optimum allocation of earthmoving equipment. The Earthmoving Equipment Management System (EEMS) functions through four integrated modules: (1) A Central Database containing information about projects and available equipment; (2) An Equipment per Segment Selection module that calculates the cut and fill quantities, plots the Mass Haul Diagrams, and selects the equipment types to be used for each segment; (3) An Equipment Pool module which determines the production and cost for each available equipment, based upon the project site conditions; and (4) An Optimization Engine equipped with a GA optimization solver. This engine formulates the optimum earthmoving cost for all projects, by changing the number of allocated equipment. The Optimization Engine takes into account the number of available equipment and calculates the weekly equipment allocation. The EEMS model was implemented on an earthmoving company conducting five different projects on hand. The model proved to be an effective tool in providing decision makers with optimum equipment utilization on a multi-project scale to minimize the earthmoving cost. The results were then compared with the company?s existing micro-level management system, demonstrating better performance on the level of savings, amounting to 13% of total earthmoving cost.

Aug 1, 2013

By Masaharu Moteki

At present, the Unmanned Construction System (UCS) is adapted on initial operation against the disaster. For instance, it has been used in Unzen. When the scale of the disaster is big, or the danger to a person is big, the UCS is expected as a quick and safe construction technology. The Remote Controlled UCS is introduced into construction site to repair earth-fill embankment or to remove rock, as urgent measures after the disaster outbreak. For improvement of the operability, shortening of the skill time, reduction of the fatigue, examination of the most suitable system (placement of a monitor and the joy stick) of the remote system is a main theme in the Public Works Research Institute (PWRI). In the report of this year, when the operator controls construction machine directly or he controls it using remote system (he can check the situation of site only via monitor), the degree of achievement, construction efficiency and construction precision were inspected. The remote system which is based on the system used at Unzen was developed at PWRI.

Aug 1, 2013

The Silvermines area of north County Tipperary in Ireland has experienced mining activity for over a thousand years, with lead, zinc, copper, barite and sulphur being extracted from a series of Carboniferous limestones. The last mine to operate in the area was closed in 1993. A legacy of contamination and derelict surface structures remain. Following the death of cattle in the vicinity in 1999, a governmental Inter-Agency Group was established to conduct an investigation. The ?Silvermines Rehabilitation Project? resulted, and included a proposal for the development of a Mine Waste Management Facility (MWMF) to act as a repository for waste materials from problematic sites across the area. The nature of the setting supported an effective solution from both a cost and performance perspective; and with limited maintenance requirements. Locating the MWMF where most wastes were identified would help minimise handling and relocation of materials. This position coincided with an area of artesian groundwater pressures. The resulting MWMF design consisted of a perimeter engineered embankment with the crest elevation designed to just exceed the groundwater piezometric surface. The base would remain unlined and groundwater permitted to rise up into and saturate the contained in-situ tailings deposits and imported mine wastes. The proposed system thus benefited from the ?wet cover? approach to minimising further oxidation of wastes and metal leaching, but without the usual accompanying outward hydraulic gradient and leachate management issues. A sub cap drainage layer with downstream outlet was incorporated to prevent any possibility of hydraulic rupture following an unexpected rise in groundwater heads. Leakage rates from the MWMF were deemed to essentially be driven by surface infiltration rates alone (characteristic of a ?dry cover? approach), with the proposed composite capping system simulated to perform at an infiltration rate of less than 1 mm per year. A toe drain was incorporated with the perimeter containment system, and this collection together with diverted neighbouring drainage was directed under gravity to a dedicated Passive Treatment System (PTS). Overall, effluent water quality from the PTS has been predicted to reflect an annual mass metals removal in the order of 95% below baseline.

Aug 1, 2013

By Shuan-cheng Gu

Roof bed separation often occurred due to the deformation incoordination of surrounding rock following the excavation of mine roadway. Bed separation has effect on the bolts, and the estimation of the influence will directly affect the safety of support systems. In this paper, the hyperbolic function model to analyze the load transfer mechanism on the bolts was simplified as the exponential function form for easy calculation. An elastic-plastic analysis model of the bolt loading occurred by the bed separation was established. And the development low that the bed separation affected to the bolt loading was discussed. According to the parameters analysis of different separation values and locations, the influence law of the bolt loading caused by roof bed separation was summarized. Finally, the effects of bed separation were considered for the bolting design, it was able to provide a reference to the anchorage design of stratified rock.

Aug 1, 2013

By Luke Meers

Roadway development rates in Australian underground coal mines are failing to keep pace with modern longwall systems and are unlikely to sustain further improvements in longwall productivity into the future unless step change improvements to roadway development equipment and practices are made. Bottlenecks which limit and constrain improved production and impact the safety of operators have been identified through a series of industry surveys, with the manual installation of strata support materials, consumables delivery, coal haulage and monorail installation being highlighted as major areas to improve development performance. This paper looks at research being carried out at the University of Wollongong in designing an integrated system approach for the fully automated handling and installing of development consumables, and the systems required to support these activities. A series of hard automation manipulation devices have been demonstrated in surface trials and the results indicate that rapid roadway development can be achieved.

Aug 1, 2013

By M. A. Nadar

Harsh and dynamic construction sites are generally equipped with cranes in order to rapidly and conveniently move heavy loads from one location to the other. If not properly inspected and managed, this operation can be very hazardous and lead to accidents. As such, a reliable and self-contained monitoring system that can update construction and safety personnel about the status of the crane, the weight of the load lifted, the location of the boom with respect to nearby buildings and other tower cranes, and the weather conditions under which the crane is operating, is deemed necessary. This can lead to significant time and cost savings as well as safety and productivity improvement due to the accuracy and immediacy of relevant on-site crane information delivery. This paper takes the initial steps and presents research targeted at evaluating the capability of wireless sensor networks (WSN) for monitoring tower crane operations in construction environments. A reliable long range WSN system is implemented and information is obtained from various special-purpose sensors (temperature, wind, proximity, etc.) mounted on special motes that relay data to and from each other and a central hub. The latter continuously monitors and manages network performance and relays incoming data to the host application. This application, in turn, displays the received data, and maps it onto a user-friendly visualization scheme, triggering alarms when a set of pre-programmed rules and safety conditions are crossed. The components of the proposed system have been tested through proof of concept experiments and preliminary results highlighted the potential of WSN systems for improving monitoring of tower cranes and reducing related accidents on construction sites, especially in Lebanon and the Middle East region where safety precautions are usually not properly implemented.

Aug 1, 2013

By T. I. Kunkel

The economic prosperity of many Canadian communities depends on resource extraction within the traditional territories of Indigenous people. The geographic sites where these resources are situated are also areas where these Indigenous people have sustained themselves for millennia through hunting, fishing, trapping, and gathering activities. These traditional activities provide not only sustenance, but also cultural and spiritual values, and the ability to transmit oral Indigenous cultures and customs from generation to generation. The multimillion dollar revenue mine project proposed within the Cariboo Chilcotin region of British Columbia is situated geographically in a location which has sustained the Tsilhqot?in people for millennia. However, this group of people have important social and cultural values nested within the traditional activities at this location. These values are typically not at the forefront of resource development. Using Indigenous research and grounded theory, this research paper briefly outlines Aboriginal values of the First Nations communities within the Cariboo Chilcotin region and some lessons learned from the Tsilhqot?in people during the environmental assessment of the mine proposal.

Aug 1, 2013

By Greg Yuriy

Over the past two decades, Vale Canada has used discrete-event simulation in a key role to support many underground mining studies. Traditionally, general purpose simulation software was developed for manufacturing and service applications. Not until recently have Mine Designers and Simulation Specialists been able to model the dynamics of underground mining scenarios without extensive manipulation of the inherent tools and entities contained within these simulation environments. This paper discusses Vale Canada?s past experiences with a variety of simulation software, describing model development methods and highlighting some of the lessons learned. The paper concludes with a review of recently considered software and provides a framework of desired attributes/functions for modeling mining scenarios.

Aug 1, 2013

By L. Chunpongtong

One of the challenges of mine planning is to determine the most cost-effective replacement time for aging equipment. The lifespan of equipment, such as haul trucks and shovels, deployed in mining operations varies due to the nature of the material and ground conditions in which it operates. For engineering economists dealing with aging equipment, the options become an economic trade-off between higher maintenance cost versus the cost of new equipment. The discount rate plays a significant role in this decision; the higher the rate, the longer the economically optimal lifespan. Therefore, the ultimate question is: ?How can the relationship between the discount rate and the economically optimal lifespan be expressed mathematically??

Aug 1, 2013

By Hevina S. Dashwood

This paper proposes to build on my previous research (Dashwood 2012), which analyzed how and why the norm of sustainable development became institutionalized in the global collaborative corporate social responsibility (CSR) initiatives of major mining companies. Since the late 1990s, the majority of major global mining companies have employed the norm of sustainable development to frame their individual CSR policies and to inform industry collaboration at the global level through the International Council on Mining and Metals (ICMM). This paper proposal seeks to address lingering questions from that research, by developing an explanation for how the normative frame of sustainable development has translated into specific CSR standards adopted by the mining industry. Preliminary findings suggest that, although the global mining industry has reached broad consensus on the meaning of sustainable development in the context of mining, there remains considerable variation between mining companies in terms of which specific global standards they adopt. As members of the ICMM, major mining companies are required to report according to the Global Reporting Initiative (GRI) indicators relevant to mining, and there has been wide-spread up-take of the ISO 14,001 environmental management system standard. However, other global standards, such as the International Finance Corporation (IFC) Performance Standards and the Extractive Industry Transparency Initiative, have not been uniformly adopted by the mining industry. What explains this variation? The paper employs a three-level institutional framework (rational choice institutionalism, historical institutionalism and the ?new? institutionalism in organization theory) to explain the influences on the adoption of CSR standards in the global mining sector. Existing research confirms that institutional context is an important factor in explaining CSR adoption in the mining sector (Dashwood 2012). Are similar forces at work in explaining the variation in adoption of specific CSR standards? A three-level institutional analysis lends itself to uncovering influences both external to mining companies (such as pressures from stakeholders), as well as internal company dynamics (such as managerial discretion). Furthermore, the framework can incorporate dynamics operating at the global level (such as isomorphism), the national level (such as the regulatory regime) and the local level (such as community needs and environmental challenges). The theoretical significance of this framework is that the influences on CSR adoption are more complex than can be explained in a single approach (such as narrow rational choice/cost benefit explanations). On a practical level, insights into how global standards get interpreted and acted upon by individual companies could lead to the development of more appropriate and effective global standards.

Aug 1, 2013

By E. Mataradze

Statistics shows that the majority of accidents with fatal outcome are caused by methane and/or coal dust explosion. This leads to assume that contemporary counter-explosion systems of various designs cannot be considered effective. Considering the growing threat of methane explosion in the coming years along with the development of deeper levels, the improvement of a system for protecting people in underground opening appears urgent. This paper presents the results of the testing of the Automatic System from Methane Explosion in Coal Mines. The protective system consists of: i) a wireless device for the detection of explosions and activation of a protective system, and ii) an absorber with a pyrotechnic device ensuring the discharge of dispersed water. The protective system, at the command of the initiation signal, produces tailored dispersing water mist with droplet sizes in the range of 25?400 ?m along selected tunnel sections.

Aug 1, 2013

By M. Kamyab

The Deep Exploration Technology project, as part of the Australian Cooperative Research Centre, is developing technologies to drill deep boreholes for mineral exploration purposes. The aim of the initiative is to transfer drilling technologies from oil and gas into mining applications. Several modifications have to be pondered due to this technology exchange: smaller cuttings sizes because of using impregnated diamond bits; narrower annulus space; higher drilling fluid velocity and likelihood of turbulent flow regime in the annulus; and higher pressure loss. In particular the results of our lab experiments have shown that the increase in concentration of small size cuttings can significantly change the rheology of the mud when drilling in hard rocks. This, in return, could have a noticeable increase in the pressure loss encountered along the annulus space. As a continuation of the above study, numerical simulations were conducted to investigate the cuttings transport behaviour in small size annulus space. Fluid velocity, annulus size, cuttings concentration, cuttings density, and cuttings size were some of the parameters that were varied to see their effects on cuttings transportation and the pressure loss along the annulus space. The results indicate that, due to the differences between oil and gas and mining drilling, conventional oil well planning is not applicable for mineral exploration drilling and numerical simulation would help in this matter.

Aug 1, 2013

By G. Mihaylov

The basic principles of systems analysis are presented. A model has been designed to determine the location of the Main opening in the presence of three or more stock orebodies. The necessary condition is to find a location for the Collection point which is an essential element in opening up each orebody (stock). The model takes into account the total transportation costs from each orebody to the collection point. Three variants are considered provided that the orefield is divided into two levels at least: - a collection point is designed at every level; - a collection point is designed at the lowest level, i.e. where the so-called concentration level is formed; - the collection point is located at a point between the planes of the two levels; The effect of the depth of mining and mine output on determining the method of opening up the orefield has been analyzed by considering a vertical and/or an inclined shaft. A function has been constructed which allows for investigating in both a static and dynamic regime the capital costs for constructing the whole complex including the shaft. The character of the function does not allow finding the global limits. Therefore, it is of particular importance to specify the limiting conditions. In this case these are the flow capacity of development openings and the shaft. The basic groups of cost and natural indicators for assessing and selecting an optimal technological solution have been systematized. The combined analysis of the two approaches to finding the location of the Main opening and determining the mining method enables us to determine when an inclined shaft is best, and the depth at which opening by a vertical shaft has no alternative. Thus, a transition area is formed for which the selection of an optimal technological solution requires an analysis similar to that proposed in this paper. Conclusions are finally drawn which serve as a basis for determining the areas of application of each opening, including the use of a combined scheme of mine opening. The approach presented can be used in both investigating the possibilities for opening up new orefields and reconstructing existing ones in cases when the mining operations go deeper.

Aug 1, 2013

By Ramsey Hart

MiningWatch Canada is the only national independent civil society organization with an exclusive focus on mining in Canada and Canadian mining companies operations internationally. In 2005, MiningWatch Canada collaborated with other NGOs to develop the Framework for Responsible Mining: A Guide to Evolving Standards. The project was the result of a perceived need by NGOs and retailers, particularly from the jewellery sector, for a framework that would set out environmental, social, and governance standards for the minerals sector ?providing recommendations for retailers and others seeking to source or invest responsibly, as well as regulate and encourage responsible mining practices?. This paper is a reflection on the Framework that examines key areas of concern and notes where the industry norms and expectations of civil society have evolved. The paper focuses on developments in social issues related to the UN Guiding Principles on Business and Human Rights, new initiatives associated with financial transparency, the UN Declaration on the Rights of Indigenous Peoples. The environmental components of the Framework that are revisited are waste management, biodiversity, energy and climate change, environmental assessment, mine closure, mercury and seabed mining.

Aug 1, 2013

An optimized long-term mine planning determines the best order of material extraction, so that the Net Present Value (NPV) becomes maximum. In the case of oil sands surface mining, one of the key constraints in NPV maximization is the volume of tailings slurry that will be generated downstream. Specifications of tailings slurry are also important from environmental perspective. Moreover, most of the material that will be used for the reclamation of tailings ponds in later periods is generated in extraction and processing of oil sands. In this paper, an integrated optimization framework is proposed to maximize the NPV of the produced oil sands, with respect to tailings capacity constraints and reclamation material requirements. A mixed integer linear programming (MILP) model is developed to find the optimal solution for long-term mine planning problem. The proposed model is coded in Matlab and has been run using CPLEX for verification. The results for real-case oil sands dataset show that the optimal production schedule meets material requirements for reclamation, tailings volume is within tailings capacity range in all periods and the production schedule follows the predetermined horizontal direction.

Aug 1, 2013

By Rita Awwad

Building Information Modeling (BIM) has been gaining a significant edge in the construction industry over the last decade. BIM allows gathering all building information in one shared database that can help all construction entities better understand, integrate and visualize all work progress from inception to operation of the building. The main purpose behind BIM is to bring all project participants together (Client, Architect, Contractor, Consultant) since the initial stages of a project allowing them to cooperate and work as a team in the promise of an increased productivity, reduced cost, enhanced quality and faster delivery. However, a full-fledged implementation of BIM tools and benefits is not yet achieved in the construction industry and remains a debatable issue for researchers and practitioners in the construction field. This paper aims at assessing BIM awareness and usage in the Lebanese construction industry through conducting interviews with contractors, architects and consultants that are key players in the Lebanese market. A comprehensive literature review about BIM adoption in some developed countries and in the surrounding region is also provided in order to better evaluate the Lebanese industry status in comparison with foreign industries. This research sheds the light on BIM awareness of the different construction parties in the Lebanese market, assesses the extent of its current use, identifies the pertaining implementation challenges, and provides recommendations to enhance BIM role in the Lebanese construction industry.

Aug 1, 2013

By John D. Nelson

Foundation underpinning is a common component of remediation schemes for distressed foundations on expansive soils. For many applications in expansive soil, micropiles have distinct advantages over other techniques. This paper will concentrate on the design and construction of micropiles in expansive soil. It discusses the nature of building distress and the relationship between foundation movement and soil heave. It presents methods for determining the factors that are required for the design of micropiles. Such factors include calculation of expected free-field heave, depth of soil wetting, and prediction of pier movement. A finite element program developed by the authors and others to determine pier heave and internal forces is presented. The input parameters that are required for pier analysis are discussed, and the nature of the output and the sensitivity of the results to the output are described. A case example illustrates the advantages of micropiles over other methods.

Aug 1, 2013

By Yi-Chun Lin

Mechanical/Electrical/Piping (MEP) systems, due to their complexity and diversity, are the most intricate part of building construction. This being the case, Combined Services Drawings (CSD) and Structure, Electric and Mechanic(SEM) drawings can ensure that all coordination issues are resolved prior to construction. Construction companies attempt to apply Building Information Modeling (BIM) to manage and integrate engineering information and solutions efficiently into the CSD and SEM processes to enhance the accuracy of design and the efficiency of review. There are several powerful commercial tools, such as Bentley Navigator, Autodesk Navisworks, and Tekla BIMsight, that can review the integrated BIM model and detect conflicts in systems, and allow planners to correct the conflict issues one at a time. However, for increasing numbers of conflicts, this may be inefficient, and requires them to be arranged in a list according to impact and seriousness before solving them. For this reason, this research implements a module for conflict impact assessment based on rule-based reasoning to classify and weigh conflict impact and seriousness, and highlight the conflicted objects in the BIM system in different colors depending on their conflict type and seriousness during the analysis. This system not only detects and lists possible conflicts and errors, but also sorts them according to the severity of impact and conflict type. Planners can effectively modify the BIM models according to these conflicts as they are listed and visualized in the BIM system. If these conflicts, such as pipeline interference and problems of insufficient space, can be avoided in the early stages of planning, it facilitates the achievement of project objectives in quality, scheduling, and cost.

Aug 1, 2013

By I. Bakry

Uncertainty is an inherent characteristic of construction projects. Neglecting uncertainties associated with different input parameters in the planning stage could well lead to misleading and/or unachievable project schedules. The objective of this paper is to present a new approach towards scheduling repetitive construction projects while accounting for uncertainty. The paper presents an algorithm that quantifies anticipated delays resulting from different sources of uncertainty in the form of fuzzy time buffers. Through inserting the time buffers in strategic places in a time schedule, the algorithm provides protection against those main anticipated delays. The presented algorithm comprises two integrated components, a scheduling component responsible for producing a basic Linear Scheduling Method (LSM) schedule with deterministic activity durations, and a buffer component that handles fuzzy buffers sizing and insertion. The presented algorithm offers four different buffer insertion techniques covering different cases of interrelations between successive activities. The algorithm is implemented in a spreadsheet application, which automates calculations, yet allows users to fine tune the algorithm to fit the project at hand. With a focuses on highway construction projects as an example of repetitive construction projects, this paper accounts for sources of uncertainty such as weather, site conditions, change orders and equipment related delays. A hypothetical case is studied and explained to further demonstrate how the proposed algorithm works.

Aug 1, 2013

By Gary MacDonald

What is the primary function of an impact assessment? Many people at the International Association of Impact Assessment?s (IAIA) annual conference said that it is time to return to the fundamentals and consider the underlying drivers of impact assessments ? human health, safety and security. This fall, managers struggling with those fundamentals will receive extra support when a new course focusing on health and socially responsible security is launched online and in British Columbia, Canada, home to many of the world?s junior miners. Now in its 33rd year, the IAIA conference recently held in Calgary, Canada, typically brings together a range of professionals who work in the impact assessment field, including academics, as well as people conducting applied disciplines, such as social and environmental performance management. It is a chance for people grappling with how to assess impacts from projects (for example, dams, mining and other extractive projects), to compare notes and to talk about developments in how to measure, track and report on them. The comments about returning to fundamentals rose as participants talked about the ongoing and increasingly recognized divergence between three main impact assessment streams: environmental, social and health (EIA, SIA and HIA, respectively). Discussions in sessions and in the corridors included calls for streamlining, for integration, for improvement and sharing of practice ? particularly in the HIA stream, where those deeply engaged in the health discipline questioned how HIAs and their intended outcome of protecting human health can be better integrated into the EIAs or SIAs that dominate the impact assessment realm. EIAs and SIAs have become the main tool, particularly from a permitting perspective for large-scale mines, but seem to leave projects with little real information about what they need to do. Human health is not the only concern re-emerging. Although not reflected at the conference, there appears to be an emerging understanding of the need to link the determinants of health with socially responsible security practices. Companies conducting independent social performance assessments for international financial institutions based on the International Finance Corporation?s Environmental and Social Performance Standards increasingly wrestle with both community health and security issues as extractive companies encounter challenging social environments around the world. Once again, the intended outcome is to better protect human health, including avoiding health impacts from conflict, abuses and violence.

Aug 1, 2013