Application of Landsat-TM Thermal Band and IRS-1A LISS II Imagery in Delineation of Coal Mine Fire in Jharia Coal Field
V. K. Srivastava
Remote Sensing Unit
Dept. of Applied Geophysics
Indian School of Mines,
Dhanbad -826004
Abstract
In this paper an attempt has been made to study and interpret the thermal band image data of Landsat-TM (day time) in conjunction with IRS-1A LISS II colour composite images of famous Jharia Coalfield (Dhanbad) India in delineation of high heat areas due to subsurface and surface coal mine fires. This high heat areas map obtained from remote sensing images have been finally compared with known fire areas map. The study has brounth out a fair correlation with know fire spots in the region, however, the affected area has since increased. Also in order to be more successful in delineation of coal mine fire through satellite remote sensing images one need to study visible and near infrared images in addition to thermal band imagery of Landsat-TM followed by high resolution aerial thermal survey.
1. Introduction
The Jharia coalfield which is the only coking coal source of India is located in the district of Dhanbad (Bihar) about w60 km NW of Calcutta. The southern edge of this coalfield is marked by perennial river Damodar. Coal min in this region was started as early as in 1890 providing a long span of hundred years of exploitation. There are 28-major coal seams. 19-in Barakar formations
(the older stratigraphic horizon) and 9-in the Ranijanj formation (the younger stratigraphic horizon).
Fires in cola seams of Jharia coalfield have been originated basically from spontaneous combustion occurring either underground or along the outcrops, and are restricated in Barakar formations with shallow depth of less than 40m. Mainly top seams which are thick and therefore more prone to spontaneous heating fires have also been caused due to burning of bantulsi, dumping of not ash in goafed out areas, illicit distillation in aabondoned working etc. There are about 20 fires spots covering an areas of 17.35 sq.k. and this coal mine fires is causing colossal loss of the country's valuable cooking coal reserved and in addition passing serious
Environmental hazard by way of degradation land, damage to settlement, soil and vegetation cover.
In order to save this valuable loss of coal reserve and also to minimise resulting environmental hazard, the current status of cola mining fire and affected areas should be known and mapped.
Conventional methods for locating such fires are not so effective due to involvement of time consuming processes and the phenomenon being the dynamic one but the modern technique of remote sensing which provides image with synoptic view of whole project area in real time and in multispectral modes including thermal infrared region has been proved to be successful in such study. Particularly with the advancement of sensor technology like optomechanical scanner system, it is possible to map thermal variation of low order over earth's surface. The interpretation of these data can range from direct visual examination of photographic recording of the measured signal based on photo-interpretation technique to sophisticated digital processing using modeling analysis and pattern recognition techniques. However these investigations are limited by the complexities of the problem both in terms of physical phenomena as well as the number of different factors that influence the result. Therefore, most of the interpretation in such studies are based on quite simple theoretical models involving very limited assumptions and farley ideal circumstances of meteorological and geological setup.
The use of thermal infrared imagery to detect subsurface coal fires is outlined in papers by slavecki (1964), Knuth (1968) and green & Moxhani (1968). In a study of 22-coal mine fires in Pennylvania, Green (1969) found that fires less than 10m depth were easily detected on thermal infrared imagery, fires between 10 and 30m in depth were detected only when heat was carried to the surface by convection in open cracks or if the fire had burned long enough (several years or more) to permit heat to reach the surface by conduction.
Success through aerial thermal sensor has also been achieved in delineating and monitoring world wide high heat areas of effusive volcanism such as in Hawai volcanism such as in Hawai Island and in Italy; and areas of steaming altered
Ground and hot spring activity in the western U.S. and areas of high heat zone in coal mining area (Jharia, Dhanbad) by various workers. Bhatacharya (1992, 1995) have also used Landsat-TM band imagery in delineating coal mine fire in Jharia Coalfied (India) by integrating ground truths collected through GPS. Shillin, Gornyi and Ermolaev Master (1987) have successfully used thermal aerial video photo images in dileneating coal mine fire area associated with coal seams outcrop in Mukunda open cast Project of Jharia Coalfied.
For this same area Mansoor, Cracknell of U.K. nad Shilin Gornyi of Russia (1994) jointly published their integrated study using NOAA-AVHRR data and Landsat-TM data in delineating coal mine fire affected area in the region. They have shown that Thematic Mapper band-5 and 7 covering SWIR have been useful in locating burning areas where as thermal infrared band 6 has been useful in separating thermal areas from back ground solar warming region. However, they are of the opinion that the coarse resolution of Landsat-TM provides picture in gross sense. In the present study mapping of coal mine fire of JCF has been taken through comparing information's of standard false colour composites images of IRS -A (1988) and Thermal band images data of Landsat-TM, of (May 1987).
2. Study Area
Jharia coalfield which is a famous coalfield of Dhanbad is about 40m in length in widths in exposed portion and in width in exposed portion and in width in exposed portion and stretches from west to east in the shape of sickle. The landscape of the area is characterised by undulating rocky and gritty surface with thin venner of insitu-soil supporting thin and sporadic vegetation. Undulating terrain with flat vallied rainfed ephemeral streams are common features. Seasonal crop is grown over valley filled alluvium/colluvium soil. Mining quarries, mine waste dump, subsidence of land surface, settlement for mining activities etc. are very common in the region.
Lower Gondana sedimentary roacks surrounded by Archaean metamorphic and granitic rocks constitute the general geology of the area. Location is shown in fig. 1.
3. Data and methodology
Landsat-TM image data band-6 (day pass of path-140 and row 044) of 1987 along with F.C.C. of IRS -1A LISS II of 1988 were analysed and interpreted with
the hypothesis that the areas above subsurface coal mine fire gets heated by conduction which will be seen as bright areas in thermal band images and will show light yellow tone in F.C.C. the image data were processed for radiometric and geometric corrections using the standard digital processed for radimetric and geometric corrections using the standard digital processing techniques at R.R.S.S.C., Kharagpur. Wide range of digital enhancement techniques were employed but linear contrast enhancement of the image data with density sliced colour coded map were found to be of much use. After the study of false colour composite and Thermal band image data a heat zonation map of Jharia coalifield covering 23o43'N-33o51'N lat to 86o9E to 86o27'E long has been prepared and compared with known fire spots as shown by open circle in Fig.2. Further the affected area of high heat zone has been calculated using PLACOM digital planimeter.
Ground checking and measurements of radiant temperature were carried out at places using Telatemp thermal radiometer as supplied by Space Application Centre, Ahmedabad (on loadn). Radiant temp(Trad) measured by the radimeter were converted into kinetic temperature (Tkin) using the formula as given below:
Trad = E1/4 Tkin
Where 'E' emvissivity of the material and Tkin is the concern traction of the kinetic heat of a body of material which is measured with a thermometer placed in direct contact with the material.
The temperature shown in the fig. 2. Is the average temperature measured by the radiometer. On high heat areas.
