Prediction for relocation scale of rural settlements based on farming radius in reclamation area of open-pit coal mine

Abstract: Mine reclamation has become a worldwide problem recently and has similar research directions both in China and abroad, including ecological restoration, mining technology, bioremediation technology, soil reconstruction techniques, soil quality testing, plant species selecting. The key target is to restore the ecological system and improve the environment. One of the main purposes of reclamation is to restore farmland, which is scarce in China. In addition, resettlement of residents and their living environment need to be taken into account. In this paper, the study area is the Pingshuo open-pit mine, which is located in Shuozhou City, Shanxi Province, China, and belongs to super-large open-pit mine with modern production. Mining activities began in 1987, and have lasted for 28 years until now. Fourteen rural settlements have moved, and resettlement population has reached 8400 by 2013. From the perspective of farming radius, buffer analysis of rural settlements was used to contrast the difference of farming radius before and after the open-pit mining by geographic information system (GIS) technology. Considering the impact of topography on farming radius, this paper calculated the terrain correction coefficient of farming radius in the study area using the achievements about relief amplitude, and the mean change-point analysis method was adopted to determine the best statistics grid unit to reflect terrain. Through buffer analysis, the result of spatial farming radius showed that the farming radius had a great change from 1986 to 2013 because of open-pit mining. Therefore, the best farming radius should be determined based on the result in 1986. Using the equation of farming radius, per capita arable land and the number of population were calculated through combining the method of "the ratio of arable land area to settlements land area " Finally, optimal farming radius was determined according to the calculation result about the terrain correction coefficient and the scale of arable land. We predicted the size and number of rural settlements after completing reclamation. The results showed that: 1) Affected by mining, the farming radius has expanded by 1500 m from 1986 to 2013, and the largest farming radius was 4500 m; 2) Determining the optimal statistics grid unit to calculate the value of relief amplitude, the result showed that 550 m × 550 m was the optimal statistics grid unit to reflect terrain in study area; 3) Based on the buffer analysis, digital elevation map neighbourhood analysis and forecasting, the terrain correction coefficient of farming radius was 1.6836, and the optimal actual farming radius was 1500 m, and therefore, the optimal spatial farming radius was 891 m. 4) On the premise of guaranteeing the arable land quantity unchanged, the total area of relocated rural settlements was about 651.24 hm2, and there were 67 rural settlements in total. Individual rural settlement area was predicted to be 9.72 hm2, and the control area of arable land was about 109.68 hm2. 5) The total relocated population would be about 29521 (7380 families). The results of this study can provide the reference for the implementment of relocating rural settlements and the reuse of reclaimed arable land in Pingshuo mining area.