A review of laser scanning for geological and geotechnical applications in underground mining

Laser scanning can provide timely assessments of mine sites despite adverse challenges in the operational environment. Although there are several published articles on laser scanning, there is a need to review them in the context of underground mining applications. To this end, a holistic review of laser scanning is presented including progress in 3D scanning systems, data capture/processing techniques and primary applications in underground mines. Laser scanning technology has advanced significantly in terms of mobility and mapping, but there are constraints in coherent and consistent data collection at certain mines due to feature deficiency, dynamics, and environmental influences such as dust and water. Studies suggest that laser scanning has matured over the years for change detection, clearance measurements and structure mapping applications. However, there is scope for improvements in lithology identification, surface parameter measurements, logistic tracking and autonomous navigation. Laser scanning has the potential to provide real-time solutions but the lack of infrastructure in underground mines for data transfer, geodetic networking and processing capacity remain limiting factors. Nevertheless, laser scanners are becoming an integral part of mine automation thanks to their affordability, accuracy and mobility, which should support their widespread usage in years to come

3D modelling of geological and anthropogenic deposits at the World Heritage Site of Bryggen in Bergen, Norway

The landscape of many historic cities and the character of their shallow subsurface environments are defined by a legacy of interaction between anthropogenic and geological processes. Anthropogenic deposits and excavations result from processes ranging from archaeological activities to modern urban development. Hence, in heritage cities, any geological investigation should acknowledge the role of past and ongoing human activities, while any archaeological investigation should be conducted with geological processes in mind. In this paper it is shown that 3D geological and anthropogenic models at different scales can provide a holistic system for the management of the subsurface. It provides a framework for the integration of other spatial and processmodels to help assess the preservationpotential for buried heritage. Such an integrated framework model is thus contributing to a decision support system for sustainable urban (re)development and regeneration in cities, while preserving cultural heritage. A collaborative approach is proposed to enhance research and implementation of combined geological and archaeological modelling for sustainable land use planning and heritage preservation, using York and Bryggen as prime examples. This paper presents the status of 3D framework modelling at Bryggen in Norway as an example

The detection and tracking of mine-water pollution from abandoned mines using electrical tomography

Increasing emphasis is being placed on the environmental and societal impact of mining, particularly in the EU, where the environmental impacts of abandoned mine sites (spoil heaps and tailings) are now subject to the legally binding Water Framework and Mine Waste Directives. Traditional sampling to monitor the impact of mining on surface waters and groundwater is laborious, expensive and often unrepresentative. In particular, sparse and infrequent borehole sampling may fail to capture the dynamic behaviour associated with important events such as flash flooding, mine-water break-out, and subsurface acid mine drainage. Current monitoring practice is therefore failing to provide the information needed to assess the socio-economic and environmental impact of mining on vulnerable eco-systems, or to give adequate early warning to allow preventative maintenance or containment. BGS has developed a tomographic imaging system known as ALERT ( Automated time-Lapse Electrical Resistivity Tomography) which allows the near real-time measurement of geoelectric properties "on demand", thereby giving early warning of potential threats to vulnerable water systems. Permanent in-situ geoelectric measurements are used to provide surrogate indicators of hydrochemical and hydrogeological properties. The ALERT survey concept uses electrode arrays, permanently buried in shallow trenches at the surface but these arrays could equally be deployed in mine entries or shafts or underground workings. This sensor network is then interrogated from the office by wireless telemetry (e.g: GSM, low-power radio, internet, and satellite) to provide volumetric images of the subsurface at regular intervals. Once installed, no manual intervention is required; data is transmitted automatically according to a pre-programmed schedule and for specific survey parameters, both of which may be varied remotely as conditions change (i.e: an adaptive sampling approach). The entire process from data capture to visualisation on the web-portal is seamless, with no manual intervention. Examples are given where ALERT has been installed and used to remotely monitor (i) seawater intrusion in a coastal aquifer (ii) domestic landfills and contaminated land and (iii) vulnerable earth embankments. The full potential of the ALERT concept for monitoring mine-waste has yet to be demonstrated. However we have used manual electrical tomography surveys to characterise mine-waste pollution at an abandoned metalliferous mine in the Central Wales orefield in the UK. Hydrogeochemical sampling confirms that electrical tomography can provide a reliable surrogate for the mapping and long-term monitoring of mine-water pollution

ENVIRONMENTAL MONITORING MANAGEMENT OF WASTE FROM LARGE EXCAVATIONS DUE TO INFRASTRUCTURE BUILDINGS

Abstract. Large infrastructure building like the Florence Railway Station designed for high-speed rails requires a proper management of the huge quantity of waste originating from excavation activities. Such waste amounts require large areas for disposals, making abandoned areas or exhausted quarries and mines ideal sites for hosting the excavated wastes.A rectangular area of 500×70m delimiting the railway station has been excavated in two steps causing the removal of a 10m-thick soil layer per step: excavated earth and rocks would then be used for the environmental restoration of an area of 400×350m located near a former exhausted lignite quarry) in the proximity of the Santa Barbara village near Cavriglia (Arezzo).The Tuscan Regional Environmental Agency (ARPAT) have been involved in monitoring both the terrain transportation and disposals' operations according to the approved management plan: the Environmental Regional Information System Office (SIRA) was asked to evaluate volume balancing between all the waste management cycle, with included: (a) waste extraction from railway station site building, and (b) waste disposal final destination (exhausted Santa Barbara lignite quarry).Terrestrial Laser Scanner (TLS), Simultaneous Localization and Mapping System (SLAM) systems and Remotely Piloted Aircraft Systems (RPAS) surveys have been used to track earth and rocks excavation and disposal activities in the aforementioned sites: while RPAS systems cannot be used in underground site surveys, their usage must be recommended in open space surveys due to the ese of use if sub-centimetric precisions are not required.Multiple TLS scans alignment can result in a quite challenging task if automatic alignment software is not available, requiring manual rough alignment's operations that can be very time consuming: two open-source solutions based on different algorithms have been evaluated.The selected survey technologies – RPAS, TLS, SLAM – have shown a great potential in earth and rocks monitoring: each technology has its own strengths and weakness, which can vary on the basis of both hardware and software technical progresses