Utilizing Coal Remaining Resources and Post-mining Land Use Planning Based on GIS-based Optimization Method : Study Case at PT Adaro Coal Mine in South Kalimantan

Coal mining activities may cause a series of environmental and socio-economic issues in communities around the mining area. Mining can become an obstacle to environmental sustainability and a major hidden danger to the security of the local ecology. Therefore, the coal mining industry should follow some specific principles and factors in achieving sustainable development. These factors include geological conditions, land use, mining technology, environmental sustainability policies and government regulations, socio-economic factors, as well as sustainability optimization for post-mining land use. Resources of the remains of the coal which is defined as the last remaining condition of the resources and reserves of coal when the coal companies have already completed the life of the mine or the expiration of the licensing contract (in accordance with government permission). This research uses approch of knowledge-driven GIS based methods mainly Analytical Hierarchy Process (AHP) and Fuzzy logic for utilizing coal remaining resources and post-mining land use planning. The mining area selected for this study belongs to a PKP2B (Work Agreement for Coal Mining) company named Adaro Indonesia (PT Adaro). The result shows that geologically the existing formation is dominated by Coal Bearing Formation (Warukin Formation) which allows the presence of remains coal resource potential after the lifetime of mine, and the suitability of rubber plantation for the optimization of land use in all mining sites and also in some disposal places in conservation areas and protected forests.


Int r oduct i on
Coal is a nonrenew able energy resource that has been t he prim ary energy resources and the m ost im portant in the w orld. Coal resources play a strategic role in econom ic and social developm ent in m any industrialized countries (W ang and Zhang, 2008;Liu et al., 2012). Coal m ining activities m ay cause a series of environm ental and socioeconom ic issues in com m unities around the m ining area. Mining can becom e an obstacle to environm ental sustainability and a m ajor hidden danger to the security of the local ecology (W ang and Zhang, 2008;Liu et al., 2012;Zhang et al., 2013). Therefore, the coal m ining industry should follow environm ental protection principles for achieving sustainable developm ent.
The rem aining of coal can be defined as coal rem ain resource (m ainly m easured and indicated) w hich are the rem aining reserves from a coal m ining activity (W estm an, 1999;W atson, 2002 andRohrbacher et al., 2009). These rem aining reserves are m ainly m easured after the m ining com panies have already com pleted contracts and their license granted by t he Governm ent has already been expired. The rem aining coal resources w ill be reevaluat ed w ith m ore com plex param eters that can influence t he sustainability of m ining and sustainable developm ent w ith reference to the recom m ended param eters of previous studies.
This study analyzes the feasibility of continuing m ining operations in term s of the possible environm ental effect s of t he operation and by considering more dynamic and com plex factors (W estm an, 1999;W atson, 2002;Rohrbacher et al., 2009;and Cryanon, 2012). These factors include geological conditions, mining technology, land use, environm ental sustainability policies and governm ent regulations, the social econom y (t he com m unity around the m ine), and the post -m ining land use sustainability. Furtherm ore, w e w ill generate a dynam ic m odeling that w ill also analyze the projected survival of rem ained coal resource for m anagem ent and optimization purposes. The follow ing is figure show ing m indset of the research.
In recent decades, there have been considerable im provem ents and em pow erm ent in the area of com puting softw are (Schm itt, 2010). M athem atical m odeling techniques have been developed to predict the locality of point event s of interest (Schm itt, 2010). Each technique can be regarded as a function that com bines the various "predictor m aps" to produce a m ap of the prospect (Bonham -Carter, 1994). The m ethod can be seen as generally fitting into one of tw o categories: know ledgedriven and data-driven. It is also possible to com bine som e features from both techniques.
AHP (Analytical Hierarchy Process) m ethod has been w idely used to assist in decision-m aking process. AHP helps the decision m akers in finding the m ost appropriate decision w ith the purpose of an specific research and understanding an issues (Saaty, 1980;Isnain and Juhari, 2013). It provides a com prehensive fram ew ork and rationale for structuring the problem to represent and m easure things that are related t o the overall objectives, and provide an alternative solution to this problem . AHP w as introduced by Thom as Saaty in 1980 using m athem atical m ethods and psychology concepts. Since then this m ethod evolved and im proved over tim e.

Sam ple And Resear ch M et hods
There are several coal m ining com panies /PKP2B (Contract of W ork) still active is in South Kalim antan province (about 14 com panies), among w hich PKP2B PT Adaro Indonesia w as select ed for this research. The com pany site is located in Balangan and Tabalong regency, South Kalim antan Province, w hich is approxim ately 220 km from Banjarm asin city to the north and can be reached by road takes about 6 (six) hours. W hile t he location of crushing (crushing plant ) and the port of loading is in the village Kelanis, in South Barito regency, Central Kalim antan (Fig. 2.). The total area of w ork agreem ent of PT. Adaro Indonesia is 35.800,80 hectares (Directorat General of M ineral and Coal, 2014).
PT Adaro has been running the m ining operation for 22 years, from the first approval of operation given by Governm ent . Recently, PT Adaro has been t he biggest coal m ining com pany in Indonesia producing coal about 50 M T per years, but lat er it going to increase to 80 M T coal per year. It has total resources approximately 4 Billion Ton coal and total reserves of coal about 2,3 Billion Ton (Directorat General of M ineral and Coal, 2014).   (Sutcu, 2012). This can be achieved through the process of defining the proof criteria, m aking evidentiary criteria m aps (predictor m aps) and w eighting by com bining these m aps to produce final prospective m ap. Interpretation m aps of these prospects can be used to generate the target area to do exploration activities (Bonham -Carter, 1994 andHarris, 2006).

AHP M et hod
This study uses a know ledge-driven approach integrated w ith GIS (Geographic Inform ation System ), i.e. AHP or the Analytic Hierarchy Process (Saaty, 1980). 1. Developing com parison matrix for each rank hierarchy, 2. Calculate the relative w eight and priority for each elem ent in the hierarchy, and 3. Calculate t he ratio of consistency to assess the consistency of assessm ent, The application of the analysis is m ainly determ ining the consistency (consistency analysis) perform ed after ranking order of each criterion. In term s of ensuring the accuracy of the assessm ent (w eighting sequence of each of the criteria used in determ ining the Eigen Value) a consistent m odeling equation is required and therefore consistency analysis w as done using tw o m ain steps (Saaty, 1980;Isnain and Juhari, 2013 Saaty (1980). RI are show n in Table 1 for n = 4. After the above st eps then calculate t he relative w eight and priority for each elem ent in the hierarchy.  GIS M odeling Approach m ethod also allow s an area know n to be free from non-m ining activities (eg land use settlem ents, highw ays, oil and gas pipelines, large rivers and other land). The analysis result s can be know n t he extent of the potential area w hich is com pletely free and clean of surface activity, so that later w ould be know n areas of optim ization for continuous m ining operations.
The sam e thing can be determ ined by overlaying m aps approaches related to the optim ization of land use. Surely m ust first set the initial criteria for the optimization of land suitability (Fuzzy logic). This study uses a guide Law no. 26 of 2007 on Spatial Planning District. Optimization of the suitability of land / land use in this research is directed to the use of plantation/ agricultural and conservation areas, w hereas the determ ination of the criteria optimization of land use can be seen in Table 4. 3. Dat a And Analysi s GIS m odeling approach also can be used to identify an area know n to be free from non-mining activities (e.g. land use settlem ents, highw ays, oil and gas pipelines, large rivers and other land). The analysis result s can be used to find the extent of the potential area w hich is com pletely free and clean of surface activity, so that later w ould be considered as areas of optimization for continuous m ining operations.
Secondary data w ere taken from PKP2B (coal com pany) and related agencies (from the level of the central governm ent and regional / Prov. Regency / City), located in the province of South Kalim antan. Retrieval of data from relevant governm ent agencies w as attained not only at the study area but also in governm ent institution that support research data. Secondary data obtained from the com pany and the institutions w ere the m ost recent data (for the past 5 years) and w ere in the form of either m aps or tables related to the research objectives The collected data from various resources w ere uniform and there w as no serious difficulties in data provision. This research w ill w as conducted in several stages of analysis: A. Analysis of the potential area coal rem aining resource for Optimization: B. Analysis of the suitability of land for land use optim ization.
For GIS modeling, Arc GIS 10.2 softw are w as used to process AHP analysis. Attribute determ ination analysis, such as polygon classification and w eighting assessm ent w as carried out to produce them atic m aps of rainfall, lithology (rock form ations), the distance from the geological structures (faults), slope and m ining progress.
3.1 Analysi s of t he coal r esour ce r em ai ni ng for Opt i m i zat i on Based on the analysis of this study the order/ranking of influent ial variables are as follow s: the relative w eight and priority for each elem ent in the hierarchy m ust be calculated. After the norm al m atrix obtained w eighting value for each criterion should be defined (Eigen Value) to be used for calculating the coal potential by the follow ing equation, PSB = FB*B1 + KSB* B2 + PL* B3 + KSG*B4 + Kal*B5 + TS*B6 + TM *B7 + Ash * B8 + KL * B9 + KT * B10 PSB = FB*0,29 + KSB* 0,20 + PL* 0,14 + Kal* 0,11 + KSG * 0,08 + TS * 0,06 + Ash * 0,04 + TM * 0,03 + KL * 0,02 + KT * 0,02 PSB is Potential Coal Area (see Fig. 7 Table 2 / random index value w ith n = 10) as the calculations show ed that the value of CR is below / less from 0.1 and is 0.039, indicating that the value of CR is consistent and acceptable.
The sam e stage is also carried out to count every sub criteria of its variable above. Further, after spread potential of coal resources is identified, Analysis of the coal resource rem aining for Optim ization is conducted by GIS M odeling approach trough carrying out overlaying potential m ap w ith infrastructure one as show n at Fig. 3. The analysis should first change spatial raster m ap into vector map to produce accurate optim ization m ap.
3.2 Analysi s of t he sui t abi li t y of land for land use opt i m i zat ion The analysis of the suitability of land for land use optim ization should base on condition of econom ic social of the com m unity around the m ining as w ell as result of the environm ental m anagem ent/ reclam ation performance of the coal com pany. The result of analysis of the coal resource rem aining for Optimization is then overlaid w ith som e supporting map, such as rainfall m ap and slope one considering criteria in accordance w ith t he Law No. 26/2007 about land pattern of the Regency area (as guidance for analyzing fuzzy logic).
In conducting analysis of suitability optim ation or land utility, This research uses criteria m ap. Som e of the m ain criteria are m ainly rainfall m ap around concession location of PT Adaro and slope m ap give significant contribution of optim ation decision of land suitability.
Analysis of GIS M odeling (Fuzzy logic) of suitability optim ation / land utility uses the criteria above and guidance of reference related to determ ining land utility w hich is accurate after post m ining. Base on The criteria include: 1. Slope, in the research area is generally 0 25 % for plantation and over 25 % for conservation land; 2. Rainfall, generally over 100 m m ; 3. Distance from street, close enough around about 1 km ; 4. Distance from settlem ent, close enough about 1 km; 5. Distance from river, close enough about 1 km ; From the consideration above, the analysis result w ould produce m ap of the suitability of land for land use optim ization. The result is hope to return land to previous function that i s rubber plantation area (Fig. 4). It is in lane w ith the and lead to increase economic rank in the Tabalong dan Balangan Regency.

South Kalimantan Province
Di scussi on Table 4. The potential area Zone of remaining coal resources The table above show s that from the initial area of PT Adaro around 35.634 Ha., The area that still has the potential to have coal resources is about 20,755.9 Ha or 58.2%. W hile the area has the potential of rem aining coal resources calculated based on the total area of PT Adaro actively reduced by the area of infrastructure is about 14,878 ha or 48.2%. If subdivided areas of potential area contain potential coal resources rem aining 10.772,9 Ha or 30.23%, w hile the rem aining area is categorized as very potential and potential.
From the above conditions can be show n that the area of PT Adaro Indonesia is still very potential to be optim ized and cultivated for sustainable m ining (SM ) is an area of 10,772.9 ha or 30.23%. Another thing is to show t hat this m ining com pany has an area of 9,983 Ha or 28.8% w hich is still feasible to continue its m ining activities even though the age of the m ine w ill end in 8 years. This condition is also supported by the com pany's statistics that the rem aining coal resource cont ent of PT Adaro's mine is still around 4 billion tons and reserves of about 2.3 billion tons and production rate of about 80 million tons.
Analysis of suitability optimation /land utility base on above criteria is that the research is propose w hen post m ining activity pt Adaro is finished. W hich is expected to be returned to the original function for rubber plantation area (Pic. 4). This is in accordance w ith the social need and encourage econom ic level in Tabalong and Balangan regency w here there has been rubber plantation processing plant. The result of this analysis show s t hat social-economic performance of the society is dominant enough.
The result analysis also indicated that environm ent perform ance does not alw ays affect directly because the perform ance of the processing surrounding of PT Adaro is still in the early stage. W here as this result has analyzed that plantation potential base on local statistic data plan give contribution significant enough out the m ining sector. Social-econom ically, it than be show n t hat plantation effort sector give contribution to sustainable developm ent. Therefore, the data of plantation sector criteria should be considered for arranging future reclam ation planning of PT Adaro (Fig. 4.). The Com pany also has an area of approxim ately 14,878 Ha or 48.2% w hich is feasible and significant to be diverted to other sectors outside m ining activities ie to achieve complete sust ainable developm ent above can be seen in the follow ing fig.

Conclusi on
Conclusions obtained from the analysis of t his study show ed that PT Adaro have the potential resource area that has sufficient rem aining coal of about 20,755.9 Ha or 58.2%., (see Fig. 3), so achieving sustainable m ining after the lifetim e of the m ine is still possible. Potential areas are generally located in t he rock form ations of W arukin and Dahor. Infrastructure land is only a little less potential area.
Based on the criteria from reference land, and the existing land use in the area and around the m ines, the land optim ization recom m ended planning a rubber plantation area and a restricted area for conservation in the north of the concession area of PKP2B PT Adaro (Fig. 4). programm ing and sim ulation to m ine planning.