We are pleased to present to you the current edition of the English Journal GeoResources.
A Word on ...
Does visualisation merely supply lovely images or is it really useful for infrastructure projects?
In Saudi Arabia, at Jeddah’s northern coastline, in the urban district of Obhur the Jeddah Tower (formally known as Kingdom Tower) is being constructed as the centre of the planned district Kingdom City. The foundation works for the Jeddah Tower constituted a major challenge due to the great length oft the foundation piles and the construction soil. Saudi Bauer Foundation Contractors Ltd., a subsidiary of Bauer Spezialtiefbau masterered the task very well as described in this article.
The need to upgrade the Alter Krog Dyke, at Nordstrand, on the North Sea peninsula in Schleswig-Holstein, had become critical, following an increase in the number of storm surge incidents, with the potential to cause damage. The project saw the first ‘climate change-resiliant profile’ on a dyke in Schleswig-Holstein, with the sea-facing slope being formed at a shallower slope than the land side. Additionally, the crest was widened, giving the potential for the dyke to be raised further, should sea level rise. This report explains how the challenges posed by the low bearing capacity soils beneath the dyke were overcome, with a cellular mattress system, comprising geosynthetics and coarse fill, used to create a stable and economical foundation.
Geotechnics and Product News
DuoLiner HGS – an innovative Protection System for producing Earth Cables and Pipelines in General
Nico Gose, Ulrike Ahlers and Jan Schröder
Construction machines frequently cause damage to pipelines during earthworks. Protection systems used customarily for trench and pipeline construction revealed potential for development and improvement during a field test. The further development of a protection geocomposite composed of a sand layer between two woven geotextile layers from landfill construction to create an innovative hydraulically bound protection membrane affords high mechanical resistance, a good signal effect and straightforward execution of laying.
Karin Bäppler, Frédéric Battistoni and Werner Burger
Tunnel alignments with variable ground conditions have become commonplace challenges for many underground projects. The conditions along the course of the tunnel often range from stable rock faces to soft, water-bearing soils. Standard technologies for shielded TBMs (Tunnel Boring Machines) have been optimized to handle a wider range of specific ground conditions. Technical and commercial limits are often reached when variable ground conditions become too large. Without major mechanical modification, innovative Variable Density TBMs combine the two basic closed mode soft ground TBM technologies, by maintaining permanent control of face pressure. This article explains the stages in developing Variable Density TBMs as well as their manner of functioning and looks at applications in major projects in France, the USA, Malaysia, Peru and Australia.
Analytical Approach to determine Gripper Pretensioning Force for Driving Tunnels with a Gripper TBM
Jürgen Schmitt and Wahid Khadr
Gripper pretensioning force represents an essential parameter for deciding on the application of a Gripper TBM for driving a tunnel in hard rock. This article deals with a new approach for calculating a simplified evaluation of the gripper pretensioning force involving only a few initial parameters.
Mining and Tunnelling
Road heading in small cross-sections in mining and tunnelling requires suitable excavation methods and machine technology. This article deals with selection criteria for conventional driving as well as partial face excavation with roadheaders and provides an overview of the machine technology available on the market.
In situ Bioleaching of polymetallic Sulphide Ores – Conditioning Methods for enhanced Permeability in crystalline Rock Formations
Ralf Schlüter and Helmut Mischo
The Bergakademie Freiberg University of Mining and Technology and the Dr. Erich-Krüger-Foundation established the “Freiberg Biohydrometallurgical Centre” (BHMZ) to foster interdisciplinary research along the entire biomining and biohydrometallurgical process chain with a focus on the extraction of indium from polymetallic sulphide ores. The objective of the BHMZ is to establish this value chain through interdisciplinary cooperation of various institutes, covering the fields of geoscience, mining engineering, microbiology as well as analytical and technical chemistry. The Department of Underground Mining Methods deals with the design and implementation of a pilot-scale underground testing facility for microbial in situ stope leaching in its “Research and Educational Mine”. Different conditioning approaches based on hydraulic and explosive methods for enhanced permeability in the rock formation are considered.
Mining and Product News
Patrick Schneider and Corinna Both
Efficient and reliable ventilation is essential for the next working field to be opened up at the new coking coal plant Uvalnaya in the Kuzbass region in the south-west of Siberia. Towards this end, the CFT GmbH Compact Filter Technic in conjunction with the Korfmann Lufttechnik GmbH has devised, manufactured and provided a new type of main mine fan after adhering to a strict timetable.
Innovative explosion-proof Switchgear for the Use in Energy Distribution Applications or as a Motor Starter
Bartec Sicherheits-Schaltanlagen GmbH
The specialists at Bartec designed a new explosion-proof switchgear for the use in energy distribution applications or as a motor starter.