Satellite based synthetic aperture radar and optical spatial-temporal information as aid for operational and environmental mine monitoring

A sustainable society is a society that satisfies its resource requirements without endangering the sustainability of these resources. The mineral endowment on the African continent is estimated to be the first or second largest of world reserves. Therefore, it is recognised that the African continent still heavily depends on mineral exports as a key contributor to the gross domestic product (GDP) of various countries. These mining activities, however, do introduce primary and secondary environmental degradation factors. They attract communities to these mining areas, light and heavy industrial establishments occur, giving rise to artisanal activities. This study focussed on satellite RS products as an aid to a mine’s operations and the monitoring of its environment. Effective operational mine management and control ensures a more sustainable and profitable lifecycle for mines. Satellite based RS holds the potential to observe the mine and its surrounding areas at high temporal intervals, different spectral wavelengths and spatial resolutions. The combination of SAR and optical information creates a spatial platform to observe and measure the mine’s operations and the behaviour of specific land cover and land use classes over time and contributes to a better understanding of the mining activities and their influence on the environment within a specific geographical area. This study will introduce an integrated methodology to collect, process and analyse spatial information over a specific targeted mine. This methodology utilises a medium resolution land cover base map, derived from Landsat 8, to understand the predominant land cover types of the surrounding area. Using very high resolution mono- and stereoscopic satellite imagery provides a finer scale analysis and identifies changes in features at a smaller scale. Combining these technologies with the synthetic aperture radar (SAR) applications for precise measurement of surface subsidence or upliftment becomes a spatial toolbox for mine management. This study examines a combination of satellite remote sensing products guided by a systematic workflow methodology to integrate spatial results as an aid for mining operations and environmental monitoring. Some of the results that can be highlighted is the successful land cover classification using the Landsat 8 satellite. The land cover that dominated the Kolomela mine area was the “SHRUBLAND/GRASS” class with a 94% coverage and “MINE” class of 2.6%. Sishen mine had a similar dominated land cover characteristic with a “SHRUBLAND/GRASS” class of 90% and “MINE” class of 4.8%. The Pléiades time-series classification analysis was done using three scenes each acquired at a different time interval. The Sishen and Kolomela mine showed especially changes from the bare soil class to the asphalt or mine class. The Pléiades stereoscopic analysis provided volumetric change detection over small, medium, large and recessed areas. Both the Sishen and Kolomela mines demonstrated height profile changes in each selected category. The last category of results focused on the SAR technology to measure within millimetre accuracy the subsidence and upliftment behaviour of surface areas over time. The Royal Bafokeng Platinum tailings pond area was measured using 74 TerraSAR-X scenes. The tailings wall area was confirmed as stable with natural subsidence that occurred in its surrounding area due to seasonal changes of the soil during rainy and dry periods. The Chuquicamata mine as a large open pit copper mine area was analysed using 52 TerraSAR-X scenes. The analysis demonstrated significant vertical surface movement over some of the dumping sites. It is the wish of the researcher that this dissertation and future research scholars will continue to contribute in this scientific field. These contributions can only assist the mining sector to continuously improve its mining operations as well as its monitoring of the primary as well as the secondary environmental impacts to ensure improved sustainability for the next generation.Environmental SciencesM. Sc. (Environmental Science

Теоретико–експериментальне обґрунтування шляхів розширення функціональних можливостей метеорологічного радіолокатора та підвищення ефективності виявлення небезпечних метеорологічних явищ за рахунок використання поляризаційних властивостей зондувальних і відбитих сигналів

1. Доведено теоретично і підтверджено експериментально закон монотонної залежності спектральної диференціальної відбиваності від доплерівської частоти у дощі. 2. Теоретично і експериментально отриманий зв'язок нових доплерівсько- поляриметричних параметрів – диференціальної доплерівської швидкості DDV і нахилу спект- ральної диференціальної відбиваності SLP з інтенсивністю турбулентності і параметрами роз- поділу крапель дощу за розміром. 3. Створена концепція багатофункціонального доплерівсько-поляриметричного дистан- ційного зондування метеорологічних об’єктів для отримання інформації про мікроструктуру об’єкта і характеристики вітру в ньому. 4. Розроблена теорія доплерівсько-поляриметричного дистанційного зондування крапе- льних опадів мікрохвильовими радіолокаторами. 5. Розроблені математичні моделі зв'язку доплерівсько-поляриметричних вимірюваних параметрів з характеристиками мікроструктури і параметрами динаміки (вітер, турбулентність) метеорологічних об’єктів з урахуванням інерційності розсіювачів, режиму зондування, харак- теристик радіолокатора, особливостей обробки сигналів. 6. Розроблені нові методи: - дистанційного виявлення зон граду за даними доплерівсько-поляриметричного спосте- реження зони огляду; - дистанційного виявлення зон імовірного обледеніння за даними допплерівсько- поляриметричного спостереження зони огляду; - дистанційного виявлення зон небезпечної турбулентності з оцінкою її інтенсивності за даними доплерівсько-поляриметричного спостереження зони огляду; - автоматичного розпізнавання типу гідрометеорів за даними доплерівсько- поляриметричного дистанційного зондування; - непрямої оцінки ефективності методів і алгоритмів та виконані відповідні оцінки щодо розроблених нових методів. Значимість отриманих наукових результатів зумовлена тим, що вони складають теоре- тико-експериментальну основу створення багатофункціональної когерентно-імпульсної метео- рологічної радіолокаційної системи здатної надавати комплекс необхідної метеорологічної ін- формації для ефективного розв’язання актуальних задач не тільки авіації, але й енергопоста- чання, мореплавства, транспорту, агрокомплексу, рибальства, прогностичних гідрологічних та протиградових служб, радіозв’язку, зокрема супутникового, інших галузей економіки, діяль- ність яких істотно залежить від забезпечення достовірного вимірювання інтенсивності опадів, турбулентності, виявлення зон підвищеної електричної активності та інших небезпечних метеорологічних явищ

Stability evaluation and prediction of the Dongla reactivated ancient landslide as well as emergency mitigation for the Dongla Bridge

The Dongla Bridge, Muli County, China, is a key access road between counties in Sichuan Province and the only traffic facility for an important 500-kV electricity substation which provides power to nearby counties. In June 2011, during the bridge construction, an unknown landslide, subsequently named the Dongla Ancient Landslide (DAL), was encountered. Local reactivation of a portion of the DAL, termed the Dongla Reactivated Landslide (DRL), was indicated by evident ground deformation at the Dongla Bridge. In spite of this, transportation of some heavy electrical equipment to the substation was scheduled on 9 May 2013. So, to guarantee the stability and security of the bridge became a primary emergency task. Detailed field investigations of the landslide occurrence, monitoring and emergency mitigation construction were carried out in the period between 2011 and 2014. This resulted in a temporary stabilization of the revived landslide and ensured the timely transportation of the heavy electrical equipment. It is thought that the revival mechanism of the DRL is creep, translational sliding, and was mainly triggered by artificial slope-cutting, but also influenced by precipitation, river erosion, and man-made activities in the form of small-scale mining operations. Following complete failure of the DRL, the probability of landslide-dam and dam breach is proved to be small by risk analyses. This paper can provide an insight into the problems associated with the interaction between the human structures and landslide instabilities

Applicability Study of A Slope Motion Monitor Using Video Motion Detection Technology

This study primarily investigates the applicability of video motion detection (VMD) technology for detecting side-slope movement. This technology involves using an economical high-resolution camera to instantly record activities, such as side-slope sliding, toppling, and movement. Concurrently, sum of absolute differences (SAD) analysis was combined with the threshold value to assess the side-slope surface movement. The physical modeling detection results showed that the VMD technology instantly detects side-slope tension crack development, rock deformation, and the location of collapsing surfaces, thereby effectively improving the effectiveness of alarms before and during disasters. Actual landslide case analysis shows that dip-slope movement is detected through gradual expansion of initial slanted rectangular red blocks and instant magnification following the block expansion on the ground level. The monitoring mechanism of VDM technology for detecting the speed and movement of debris flow can be used as a reference in disaster prevention and evacuations of people living in downstream areas. Furthermore, this study generalizes the limitations of VMD technology. These generalizations can be used as a reference for future slope surface movement monitoring and related studies.本文主要探討影像感測技術於邊坡運動監測之適用性，藉由低成本、高解析度攝影機即時記錄邊坡滑動、傾倒及流動等過程，並以絕對差值分析法搭配門檻值評估邊坡地表運動過程。物理模型感測結果顯示，採用影像感測技術可即時偵測邊坡張裂隙發展、岩體變形與地表瞬間崩壞之區位，有效提升災前及災中預警之成效。實際山崩案例分析發現，順向坡滑動之感測特徵由初始傾斜長條型紅色區塊逐漸增加範圍，最終塊體於地面擴散後將造成紅色區塊瞬間擴大。而影像感測技術對於土石流速度及流動狀況之監測，亦可作為下游保全對象防災疏散之參考。此外，本研究亦初步歸納影像感測技術之應用限制，期能作為未來邊坡地表變動監測與相關研究之參考

Behaviors of Pipe-Soil Interaction on Unstable Slopes by Finite Element Simulation

Pipe-soil interaction plays an important role to the pipe stress analysis subjected to soil movement due to slope instability and/or slope failure. As the soils / slopes begin to fail, a single pipe or a group of pipes buried inside failure zone will bear additional loads which frequently lead to overstress or buckling. To study this phenomena, a case study was carried out by modelling a group of pipes subjected to ground movement in lateral direction. ABAQUS, a finite element software was employed to establish a 3 D numerical model of pipe-soil interaction during landslide event. Discussions of the results of this analysis are presented by focusing on the behaviors of displacement and stress of the pipes due to slope failure. Based on the analysis results, the length of failure zone becomes the major cause of the location of maximum stress during slope failure, it should be assessed carefully

Digital elevation models for landslide evolution monitoring: application on two areas located in the Reno river valley (Italy).

open9noGPS, digital photogrammetry and laser scanning techniques have been applied and compared in the frame of the studies of two complex landslides located in the Emilia-Romagna Region (Northern Italy). The three approaches, characterized by different accuracies, applicability and costs, have demonstrated to be efficient tools to define Digital Elevation Models computed in the same reference system and able to provide data on the landslide motion. The results described in the paper indicate the present low level of landslide activity in recent years. Reliability, costs and execution times of the applied surveying methods are shown and discussed in this paper.openPESCI A.; BALDI P.; BEDIN A.; CASULA G.; CENNI N.; FABRIS M.; LODDO F.; MORA P.; BACCHETTI M.PESCI A.; BALDI P.; BEDIN A.; CASULA G.; CENNI N.; FABRIS M.; LODDO F.; MORA P.; BACCHETTI M

Ancient Landslide Reactivation at the Viaduct No. 1 Located on the Caraca-La-Guaira Highway in Venezuela

Reactivation of an ancient landslide detected in 1987 affected the southern side of the Viaduct No.1 located in the Caracas-La Guaira highway, which connects Caracas, capital of Venezuela, with its main seaport and the Simon Bolivar International Airport. The Viaduct was built in 1953 and covered a gorge of approximately 300 m. It consisted of three parallel double-hinged arch ribs made of plain concrete spanning over approximately 152 m and two smaller access Viaducts on either side of the arch rib span. This paper summarizes the results from geotechnical investigation, the evaluation of inclinometers readings and surface control points and the main rehabilitation measures conducted on the structure

The dynamics of reactivated landslides: Utiku and Taihape, North Island, New Zealand

The primary aim of this research was to study the relationship between landslide motion and its causes, with reference to large, slow moving, reactivated translational rock slides. The movement of such slides has often been assumed to be uniform over time because poor temporal and spatial monitoring resolutions have not allowed the processes and mechanisms governing the velocity to be identified. The increased spatial and temporal resolution of the monitoring carried out for this research allows these processes to be better understood. Two deep-seated, reactivated translational slides were selected to represent over 7,000 mapped landslides of this type in Tertiary-age sedimentary rocks of New Zealand. Each was closely monitored with an automated network of instruments to detect and measure the effects of rainfall, pore pressure, earthquakes and river stage on changing surface and subsurface movement patterns, with sufficient resolution to link periods of movement to their triggering factors. The dynamics and controls upon these landslides have been investigated by combining multiple interdisciplinary approaches including geology, geomorphology, geotechnics and geomatics. Without such an approach the mechanisms governing their motion could not have been adequately resolved. The deformation behaviour at the two slides during the period of observation would best be described as episodic post-failure creep. The creep patterns observed typically comprised periods of accelerated-, slow- and vertical-creep, punctuated by intervals of rest, which recurred both seasonally and independent of season. Three systems were identified within the recorded unsteady, non-uniform motion: 1) basal sliding; 2) internal plastic deformation and basal sliding; and 3) seasonal surficial shrinkage and swelling unrelated to landsliding. Basal sliding by frictional slip along thin clay seams led to the largest horizontal displacements recorded at both landslides. However, once triggered by pore-pressure increase, accelerated-creep motion by basal sliding did not tend to arrest when basal pore pressure decreased. At both landslides slow horizontal- and vertical-creep occurred together over much of the monitoring period and was related to plastic deformation of the slide mass and basal sliding. This motion occurred at a constant velocity and did not vary with fluctuating pore pressure. Accelerated- and slow-creep motion was regulated by the geometrical complexity of the landslide mass rather than basal pore-pressure-induced increases in shear resistance, or rate-induced increases in material shear resistance

Digital elevation models for landslide evolution monitoring: application on two areas located in the Reno River Valley (Italy)

GPS, digital photogrammetry and laser scanning techniques have been applied and compared in the frame of the studies of two complex landslides located in the Emilia-Romagna Region (Northern Italy). The three approaches, characterized by different accuracies, applicability and costs, have demonstrated to be efficient tools to define Digital Elevation Models computed in the same reference system and able to provide data on the landslide motion. The results described in the paper indicate the present low level of landslide activity in recent years. Reliability, costs and execution times of the applied surveying methods are shown and discussed in this paper