Stability issues in natural and man made slopes in mining

Valenzuela, Luis

doi:10.1201/b16816-66

Cited by 9 publications

(17 citation statements)

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“…The high rate of movement of the rock glacier (maximum 30-35 m/year) was caused by loading of mine waste material of up to 30 m thick (Apablaza et al, 2001). The displacement rate of the rock glacier before the deposition ranged between (Contreras and Illanes, 1992;Valenzuela, 2004;Brenning and Azócar, 2010). The normal, relatively slow, movement of rock glaciers and debris-covered glaciers has also generated minor problems in the operation of ski lift towers in Morenas Coloradas, Central Andes of Argentina (D. Trombotto, personal communication, 2012) and also destroyed part of a mountain hut near Laguna del Diamante, East flank of Maipo Volcano (Alonso and Trombotto Liaudat, 2013).…”

Section: Other Processes and Hazards Related With Glaciers And Permafmentioning

confidence: 99%

Hazardous processes and events from glacier and permafrost areas: lessons from the Chilean and Argentinean Andes

Anacona

Mackintosh

Norton

2014

Earth Surf Processes Landf

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Glacier and permafrost hazards such as glacial-lake outburst floods and rock-ice avalanches cause significant socioeconomic damages worldwide, and these processes may increase in frequency and magnitude if the atmospheric temperature rises. In the extratropical Andes nearly 200 human deaths were linked to these processes during the twentieth century. We analysed bibliographical sources and satellite images to document the glacier and permafrost dynamics that have caused socio-economic damages in this region in historic time (including glacial lake outburst floods, ice and rock-ice avalanches and lahars) to unravel their causes and geomorphological impacts. In the extratropical Andes, at least 15 ice-dammed lakes and 16 moraine-dammed lakes have failed since the eighteenth century, causing dozens of floods. Some floods rank amongst the largest events ever recorded (5000 × 10 6 m 3 and 229 × 10 6 m 3 , respectively). Outburst flood frequency has increased in the last three decades, partially as a consequence of long-term (decades to centuries) climatic changes, glaciers shrinkage, and lake growth. Short-term (days to weeks) meteorological conditions (i.e. intense and/or prolonged rainfall and high temperature that increased meltwater production) have also triggered outburst floods and mass movements. Enormous mass failures of glaciers and permafrost (> 10 × 10 6 m 3 ) have impacted lakes, glaciers, and snow-covered valleys, initiating chain reactions that have ultimately resulted in lake tsunamis and far-reaching (> 50 km) flows. The eruption of ice-covered volcanoes has also caused dozens of damaging lahars with volumes up to 45 × 10 6 m 3 . Despite the importance of these events, basic information about their occurrence (e.g. date, causes, and geomorphological impact), which is well established in other mountain ranges, is absent in the extratropical Andes. A better knowledge of the processes involved can help to forecast and mitigate these events.

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Section: Other Processes and Hazards Related With Glaciers And Permafmentioning

confidence: 99%

Hazardous processes and events from glacier and permafrost areas: lessons from the Chilean and Argentinean Andes

Anacona

Mackintosh

Norton

2014

Earth Surf Processes Landf

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“…A ello se agrega el valor no relacionado al uso, como el de su existencia, de legado y altruista (Kronenberg, 2009). Por otro lado, en el aspecto económico los glaciares rocosos también pueden tener un valor negativo al crear una barrera al desarrollo de un proyecto o al causar daño por su movimiento o colapso (Grebenets et al, 1997;Burger et al, 1999;Valenzuela, 2004;Kääb et al, 2005;Kääb et al, 2007).…”

Section: Rol Ambientalunclassified

“…La posible degradación del permafrost de los glaciares rocosos por efectos geotérmicos y geoquímicos (Acid Rock Drainage) y la agradación de permafrost con variables contenidos de hielo en el material depositado tienen incalculables consecuencias en el largo plazo (décadas a siglos) para la estabilidad de la forma (Grebenets et al, 1997;Hollesen et al, 2009). El colapso de un glaciar rocoso recubierto con depósito de lastre no solo causaría daños en las cercanías, sino también debe considerarse la posibilidad de que la mezcla de detritos, hielo, y material de arrastre -en particular, agua y lodos de estanques de relave-se convierta en un fl ujo detrítico capaz de desplazarse largas distancias (Valenzuela, 2004;Brenning, 2008). El derrumbe y fl ujo detrítico del río Colorado en 1987 (Casassa & Marangunic, 1993) es un ejemplo natural de este tipo de movimiento en masa que puede afectar a asentamientos humanos localizados a gran distancia del origen del derrumbe.…”

Section: Tipología De Intervenciones Y Sus Efectos Ambientalesunclassified

“…Los glaciares rocosos en el área de Los Bronces y la vecina División Andina de Codelco (Región de Valparaíso) fueron los primeros que se han estudiado en Chile (Lliboutry, 1961). Los impactos sobre glaciares rocosos han sido ampliamente documentados en el área, especialmente aquellos generados por el depósito de lastre sobre el glaciar rocoso Infi ernillo (Contreras e Illanes, 1992; Valenzuela, 2004;Brenning, 2008). De los 1,9 km² de glaciares rocosos en Los Bronces, se estima que hasta el 1997 un área de 0,2 km² de glaciares rocosos fue afectada -presumiblemente removida-como consecuencia del crecimiento del rajo de la mina; otros 0,2 km² fueron cubiertos por el depósito de lastre Infiernillo (descrito más adelante con más detalle), y 0,4 km² son afectados por la construcción de infraestructura, principalmente caminos (Brenning, 2008).…”

Section: Intervenciones En Glaciares Rocosos En Chileunclassified

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Minería y glaciares rocosos: impactos ambientales, antecedentes políticos y legales, y perspectivas futuras

Brenning

Azócar

2010

Rev. geogr. Norte Gd.

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El interés científi co y político en los glaciares rocosos andinos ha aumentado fuertemente en los últimos años debido al creciente reconocimiento de su importancia hidrológica y las recientes intervenciones mineras en ellos. Se presenta un resumen de los conocimientos científi cos y el marco político-legal de las intervenciones pasadas y actuales en glaciares rocosos en Chile y, en forma preliminar, en Argentina y Perú. En estos países, 26 faenas mineras han afectado glaciares rocosos o podrían posiblemente intervenirlos en el futuro. Hasta la fecha, el área afectada de glaciares rocosos en Chile es de aproximadamente 3,3 km 2 . Se recomienda ampliar el actual debate sobre intervenciones en glaciares rocosos, basado en la actualidad principalmente en argumentos hidrológicos, para tomar en cuenta peligros ambientales en el largo plazo -como la posible inestabilidad de glaciares rocosos con depósitos mineros-como también la amplia gama de servicios ambientales brindados por los glaciares rocosos.

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“…Coal mine spoil pile instability is relatively common, with several failures well documented in literature (Upadhyay, Sharma & Singh 1990;Valenzuela 2004;Pisters 2005;Srour 2011). …”

Section: Geotechnical Stability Of Coal Mine Spoilsmentioning

confidence: 99%

Bulking and Subsequent Self-Weight and Saturation Settlements, and Geotechnical Stability of High Coal Mine Spoil Piles

Kho¹

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To satisfy the ever increasing global and domestic demand for coal, many coal mine operators in Australia, with thick coal seams at depth, are investigating the feasibility of deep open pit mining. Pit depths of up to 500 m have been proposed, with projected spoil pile heights of up to 600 m. The increased thickness of overburden becomes a significant issue, as this increases the amount of spoil produced. Mine operators then have to decide where to place spoil in the early stages of mine planning. Therefore, the parameters on which decisions are made have to be determined up front, to accurately estimate the net present value costs necessary to prove the financial viability of deep open pit mining at a given site.The mechanisms that cause spoil volume change are: bulking, self-weight settlement, saturationinduced collapse and degradation, all of which act together to alter the shape and height of spoil piles.Thus, the understanding of these volume change mechanisms is critical to the design, sizing, geotechnical stability and cost estimation of an open pit coal mine.This thesis documents the research, funded by Australian Coal Association Research Program (ACARP) Project C19022, aimed at investigating the effects of settlement and strength of coal mine spoil. As part of the research, several mine sites were visited. Representative spoil samples were collected and were subjected to a comprehensive laboratory testing programme.Laboratory direct shear testing undertaken in two sizes, 60 mm square and 300 mm square, found that coal mine spoil materials are best characterised as having low cohesion (generally less than 10 kPa) and reasonably high friction angles (generally greater than 30°). On testing under dry conditions, the friction angle is typically in the range from 27 to 35°, while on testing under wet conditions, the friction angle decreases to the range 20 to 34°. Wetting up is seen to cause some reduction in strength, especially for the weakly-cemented and highly plastic spoils.Laboratory compression tests were performed on two sizes: the standard 76 mm diameter oedometer, capable of stresses up to 1 MPa, and the 150 mm diameter high stress oedometer, capable of stresses up to 10 MPa. Self-weight settlement of initially dry spoil was found to be up to 45% of initial height iii at 10 MPa stress. Of this, about 80% is expected to occur during placement and is thus not 'seen'.Collapse settlement on wetting up was found to cause additional settlements of up to 15% at stresses of about 500 kPa, decreasing to about 5% at 10 MPa stress. Negligible further collapse is expected after a collapse event, since water merely fills the voids between particles. In addition, test results indicated that the void ratio of coal mine spoil approached values of 0.3 to 0.35, corresponding to dry densities of between 1.95 and 2.1 t/m 3 , at 10 MPa applied stress, regardless of moisture state, maximum particle size, scalping method and magnitude of initial loading.As part of the research, a degradation test method was deve...

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Stability issues in natural and man made slopes in mining

Cited by 9 publications

References 0 publications

Hazardous processes and events from glacier and permafrost areas: lessons from the Chilean and Argentinean Andes

Hazardous processes and events from glacier and permafrost areas: lessons from the Chilean and Argentinean Andes

Minería y glaciares rocosos: impactos ambientales, antecedentes políticos y legales, y perspectivas futuras

Bulking and Subsequent Self-Weight and Saturation Settlements, and Geotechnical Stability of High Coal Mine Spoil Piles

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