Abstract

Iran’s coal bearing sediments are within the Upper Triassic to Middle Jurassic Shemshak Group. These sediments are developed in the northern, central and eastern part of Iran. Two coal bearing basins have been established, one in central Iran and the other along the Alborz mountain ranges. The central basin, known as the Tabas coal bearing basin, with an areal extent of 45,000 km² is constrained by the Nayband fault on the east and the Naeini fault to the west. This extensive basin is divided into three coal regions in which geological-tectonic conditions and qualitative/quantitative parameters are varied. In one of these regions, known as Parvadeh, a resource of one billion tons of coking coal has been substantiated. The Shemshak Group within Parvadeh is Late Triassic to Middle Jurassic in age. It consists, from oldest to youngest, of the Nayband, Ab Haji, Parvadeh and Baghamshah formations. Economic reserves of coal are found within the Nayband Formation. This formation has been further sub-divided into five members and stratigraphically from the base comprises the Gelkan, Bidestan, Howze-Sheik, Howze-Khan and Ghadir members. It is within the Ghadir member that mineable coal measures are developed. The Ghadir is 1000 m thick in the Parvadeh area and consists of cyclic successions of coarsening upward elastics comprising very fine grained argillite (claystone), fine grained siltstone, coal, minor limestone and fine to coarse grained sandstone. To date 200,000 m of core drilling have characterized with considerable detail the stratigraphy of the Ghadir, quantified the reserves and established a structural geological framework. Wrench fault tectonics govern the structural style evident in Parvadeh today. Bounding north-south trending and interconnecting east-west trending regional strike slip faults, as well as a swarm of smaller scale northeast-southwest faults segment the area into discrete blocks. In addition, a series of anticlines and synclines with east-west trending fold axes are associated with this regional faulting. The presence of monoclinal extensions to this folding have provided areas and consequently mining blocks of low dipping, structurally undisturbed coal mining reserves. A mine feasibility study to produce an average 1.67 million tonnes of coking coal per year is in progress.