Heavy metals content and pollution in tin tailings from Singkep Island, Riau, Indonesia

Instead of its economic impact, tin mining activities cause environmental problems. The tin occurrence which is related to tin-bearing alteration on S-type Muncung Granite and its mining history in Singkep Island describes in this study. This work assessed the heavy metals concentration in six tin tailings and two soils from Singkep using inductively coupled plasma - mass spectrometry in correlation to environmental hazard. Both primary and placer mining methods applied in tin excavations on the studied area. Concentration tendency of heavy metals in the six studied tailings samples is generally Cr>Pb>As>Ba≈V. The identical heavy metals trend represented by the three samples from Bukit Tumang might reflect a similar primary tailings character. On the other hand, anthropogenic activities and different surrounding rocks caused the dissimilarity of heavy metals pattern on placer wastes. Higher environmental problems are detected on the primary wastes than the placer one, especially arsenic and chrome. Severe arsenic pollution degree is also indicated in the soil sample just outside the mining location at Betong Village. Conservation and amelioration programs are useful in improving the environmental condition on studied locations

The geodiversity site of Sentono Gentong in Pacitan, Indonesia: Geological characteristics and quantitative assessment

This paper aims to identify the geological properties of Sentono Gentong and provide a quantitative assessment of its geodiversity site in Pacitan Regency, Indonesia.This area is an integral part of the vast Gunung Sewu UNESCO Global Geopark. Rock samples and site conditions are compiled on field study. The study area consists mainly of Neogene limestone and older igneous rock. Microscopic analysis has revealed that the limestone is composed of bioclastic wackestone, boundstone, and fossiliferous wackestone. The igneous rock in the area is a grey-black hornblende andesite. Bangunsari fault, which cuts through the study area, disturbs the coastal terraces to its south. The results of the quantitative assessment show that the site's potential educational use, potential touristic use, and degradation risk scores are 92.5, 80, and 56.25, respectively. The assessment scores describe the site as having potential for education and tourism uses, with a medium risk of degradation. Quite prominent cultural elements, which form the local community's identity, are included as a complement to the identification of the site. In order to preserve and maintain the sustainability of this potential geodiversity site, a high commitment related to geoconservation is required

Thermal history analysis of selected Chilean, Indonesian and Iranian porphyry Cu-Mo-Au deposits

This paper presents U-Pb-He triple dating age determination for several porphyry Cu±Mo±Au deposits in Chile, Indonesia and Iran in an effort to determine their thermal histories and to explore the effects of cooling/exhumation rates on ore formation and preservation processes. Inverse thermal modelling of measured time-temperature history data from these deposits was conducted to quantitatively constrain the depth of emplacement, duration of ore deposition, exposure ages and cooling/exhumation rates. The duration of hypogene ore formation for the deposits studied generally occurs within timeframes of 10⁵ years, although modelling results for the Grasberg, Batu Hijau and El Teniente super porphyry deposits suggest formation periods of the order of 10⁴ years. Emplacement depths on intrusions associated with porphyry mineralisation range from 800 m to 5500 m from the palaeosurface, with the Grasberg and Rio Blanco being respectively the shallowest and deepest super porphyry deposits studied. The thermochronology data indicates a positive correlation between metal grade and cooling rate during hypogene ore formation, but further investigation is warranted. Exhumation rates varying from 0.3 to 1.1 km/m.y. have implications for the preservation potential of hypogene ore deposits, with super porphyry deposits like Sar Cheshmeh potentially losing 3.5 Mt of copper to erosion over the last 5 million years. The potential for supergene ore formation under such conditions is high, as is the potential for the formation of proximal Exotica-type deposits.16 page(s