by :
Anggoro Tri Mursito
Research Centre for Geotechnology
Indonesian Institute of Sciences (LIPI)
Jl. Sangkuriang, Komplek LIPI Gedung 70, Bandung 40135
anggoro@geotek.lipi.go.id
abstract
An artificial soil mixed made out of electrical-coal power plant wastes (fly ash) and material from the coal mine sites (clay and gravel G5) has been created for the reclamation of open pit mine site. Physico-chemical properties were measured over time to examine them in a chronosequence of 22 plots (each 400m2) with systematically changing mixtures (1,2 and 3 components of varying proportions were established and planted. In the field plots, available nutrient content was initially high but established only for some of plots. Due to ecological function measurement, physical parameter, which is hydraulic conductivity, is one of several physic properties will have to be monitored and analysed.
According to the development value of the year of 2003 (spring) shows that increasing of water permeability classes (class 6) is leaning to the direction of fly ash and tegel (clay) composition. Class 5 are only in the trial plot number 5 and 9. Only in one trial plot which is drop in class 4 (trial plot 16), but it is still classified into “good” class (according to “Arbeitskreis Standortskartierung, 1996”). The trial plot number 1 has also classified into class 6, because the substrate composition in this trial is only 100% of gravel. It has to be the highest class, but it is not always the highest value of water permeability. All the trial plots are classified into high to very-very high. Compared results between initial (spring, 2000) and recent measurement (spring, 2003) is shown that extremely increased in the trial plot 3 and 13. In the year of 2003, in trial plot number 3 and 13 are suddently flare up to 4 classes (from class 2 to 6). As also analysed by Computed Tomography images of one component substrate (100 % of tegel) shows that cracked structures clearly appear as a results of decreasing precipitation in the last winter and also highly increasing of temperature as well. High percentage of cracked means that water can easily flows. Most of the trial plots are increasing of classes due to the season differences. The others (trial plot number 1, 5, 6 and 9) remain in the same class.
Same grade doesn’t means that same value of water permeabilty as well, but e.g. trial plot 1 has same class compared to the result in 2000 and that means very very high.
From : The 33rd Annual Convention & Exhibition 2004 Indonesian Association of Geologist