Vol. 15, Issue 2 (July-Dec 2005)

Abstracts

• Marios Leonardos (Public Power Corporation, Valtinon 76, GR-114 74 Athens, Greece): "Pore water pressure changes and measurement for slope stability in the mining industry." Mining & Metallurgical Annals, vol. 15, no. 2, July-Dec 2005, pp. 19-30.

The pore water pressure is an essential parameter for the estimation of the available shear strength during slope stability calculations. Water levels from observation wells, very common in mining practice, are not always a reliable indication about the pore pressures in the slope soil mass. During slope excavation and as a result of total stress reduction, a pore water pressure drop is observed, which is followed by a gradual recovery up to the level determined by the formation of the new water table. On the contrary, during overburden material dumping or tailings disposal, especially rapid dump or dam height lift, a pore water over-pressure is observed, which is followed by a gradual drop up to the level determined by the formation of the new water table. The result of these pore water pressure changes is that the "end of construction" condition is favourable for excavation of mine slopes but critical for tailings dams and spoil banks.

The vibrating wire piezometers are suitable for long-term monitoring of pore water pressures to determine safe rates of fill or to estimate excavation slope stability. Piezometers are lowered to the specified depth, and the borehole is simply backfilled with a bentonite-cement grout. This installation method is simpler and more reliable, especially for a multi-piezometer borehole. The vibrating wire piezometers are suitable for automatic data acquisition systems to cover continuous monitoring in sensitive operations as tailings dams. (Article in Greek.) © Mining & Metallurgical Annals, Hellenic Society of Mining & Metallurgical Engineers, 2005.

• Dimitrios Mendrinos and Constantinos Karytsas (Center for Renewable Energy Sources, 19th km Marathon ave., GR-190 09 Pikermi Attiki, Greece): "Geothermal energy and geothermal heat pumps: the CRES experience." Mining & Metallurgical Annals, vol. 15, no. 2, July-Dec 2005, pp. 31-50.

Geothermal energy is the heat of the earth. It includes hot dry rock, the exploitation of which is in experimental stage, the high enthalpy geothermal fields, which are mainly exploited for power generation, the low enthalpy fields, which are mainly exploited for heating of buiuldings, greenhouses and soil and thermal baths, and shallow water bearing horizons and soils exploited for heating and cooling with geothermal pumps. The overall cost of geothermal power generation, including capital amortization and the cost of money, amounts at 0.05-0.09 EUR/kWh(e), of thermal applications at 0.005-0.035 EUR/kWh(th), and of geothermal heat pumps at 0.038-0.048 EUR/kWh. The corresponding markets (2002) in European Union include 720 MW(e) power generation and 1650 MW(th) thermal applications with 5% annual growth rate, and 3340 MW(th) geothermal heat pumps with 30% annual growth rate. In Greece, there are 69 MW(th) thermal applications and baths and ~100 geothermal heat pump units. Selected applications include the Traianoupolis spa hotel, the Town Hall of Pylaia, the European Centre for Public Law, the building of the National Technical University of Athens (NTUA). Geothermal energy benefits are environmental, financial and social. The main problems related to the exploitation of high and low enthalpy geothermal energy are associated with the chemical composition of the liquid and steam phases, which can be effectively solved by reinjection, eliminating steam emissions, proper plant design and chemical treatment of the fluid. Market barriers associated with geothermal heat pumps are mainly of commercial nature. A new legal framework for geothermal energy use in Greece has been completed recently. (Article in Greek.) © Mining & Metallurgical Annals, Hellenic Society of Mining & Metallurgical Engineers, 2005.

• Georgios Panagopoulos, Nikolaos Lambrakis and Konstantinos Stratikopoulos (University of Patras, Department of Geology, Section of Applied Geology and Geophysics, GR-265 00 Rio, Patras, Greece): "The contribution of multivariate statistical analysis to the hydrochemical research." Mining & Metallurgical Annals, vol. 15, no. 2, July-Dec 2005, pp. 51-73.

The application of multivariate analysis on the hydrochemical data of the Trifilia karst aquifer has confirmed statistically the existing hydrochemical processes and their contribution to the configuration of the hydrochemical character of groundwater. The application of factor analysis on two different sets of data discriminated factors with a common geochemical interpretation, such as the salinization and geothermal factors. Furthermore, the application of factor analysis on the trace element concentrations demostrated the influence of hydrocarbons on the chemical composition of groundwater, since it classified the redox sensitive metals in two different factors. The discriminant analysis led to the conclusion that the most important hydrochemical process is the groundwater salinization, since the electrical conductivity plays a major role in the classification of samples in the five hydrochemical zones. (Article in Greek.) © Mining & Metallurgical Annals, Hellenic Society of Mining & Metallurgical Engineers, 2005.

• Petros G. Tzeferis (Ministry of Development, Mesogeion 119, GR-101 92 Athens, Greece): "Sustainable development of Greek mineral resources: an environmental dilemma." Mining & Metallurgical Annals, vol. 15, no. 2, July-Dec 2005, pp. 75-92.

The Greek mining-extractive sector, despite its strategic advantages among other EU countries and also its important history of many centuries, seems not having sufficiently acknowledged the necessity to adapt to new tendencies, including to the principles of sustainable development, which entails the unification of economic development and social responsibility.

The environmental impact, the safety factor, the quality of life, the social concerns are major political questions that if combined with the increasing need for briefing, awareness and mobilisation of citizens, require a new consideration for technology: a human-oriented technology in a constantly modulating globalised environment; a technology that treats environmental matters with the appropriate respect to mankind, thus leading to a better quality of life through environmental appreciation.

Development without cost does not exist. Between the "aggressive" extractive industry, which imposes risks for the environment, on the one side and "sustainable nothing" on the other side, we believe that we should choose a third way so that both development and protection of the environment are equally achieved.

Sustainability in mineral resources management could be achieved by reducing the environmental impact of the extractive industry and by establishing the best available approaches and techniques for land reclamation and for the treatment of mining wastes. But this is not enough. It is vital that an effective communication policy is applied to promote the dialogue with the local communities as well as the central administration. This dialogue has to be clear, transparent, constructive, complementary, consensus-making and not contradictory. It should reflect our anxiety and effort to protect and reclaim the environment for the benefit of our society and the national economy as a whole. We should redefine the meaning and significance of business profit so that it will include news dimensions such as the environmental protection, the education and the culture, which are the real profit for mankind. Otherwise, we may witness a progressive minimization or even degeneration of the mining sector. In that case, we don't have to ask for whom the bell tolls; it tolls for all of us… (Article in Greek.) © Mining & Metallurgical Annals, Hellenic Society of Mining & Metallurgical Engineers, 2005.

You may obtain copies of the above articles by writing to the Journal at the address:

Mining & Metallurgical Annals

Epirou 24,

GR-104 64 Athens

Greece

Tel./Fax: +30-210-8628514