Comment
Author: Admin | 2025-04-28
And 139.07 for mining impact and control areas, respectively. However, the range of fluctuations in values for control areas was much greater, with quartile distances ranging from 49.54 (WS) to 1.09 (RM), while the interquartile range for the mining impact areas was only between 18.00 (SFR) and 0.48 (RM). An independent t-test was performed to test whether there was a significant difference between the mining impact and control areas. The results showed that there was a significant difference, as the p-values for BP, CR, F, GR, RC, RM, SFR, WS and WT were all less than the 0.001 level of significance. However, by 2020, the mean values of BP, CR, GR, SFR, WS and WT in the control areas exceeded those in the mining impact areas. The median values of SFR were 156.72 and 157.24 for the mining impact and control areas, respectively. The median values of WS were 53.33 and 58.62, and those of WT were 106.03 and 113.07, respectively. The quartile spacing remained stable from 1990 to 2020. The results of the significance test showed that the p-values of BP, CR, F, RC, RM, SFR and WT were less than the 0.05 level of significance and indicated significant differences.The impact of opencast mining on the trend of ESV changesThe trend of ESV changes in the opencast mining areasWe used the Sen + MK test to calculate the spatial distribution of the trend of ESV changes based on the grid scale, as shown in Fig. 5, during the period 1990–2020, the ESV in the study area showed an overall improving trend. The areas with improved ESV were mainly distributed in the western and north-eastern parts of the study area, while the areas with degraded ESV were mainly located in the south-eastern, north-central and south-central parts, which had a high degree of overlap with the distribution of mining concessions; statistical results show that 67% of the extremely degraded areas in the study area are located within the boundaries of mining concessions. Table 5 summarises the areas of each type of ESV change from 1990 to 2020. It can be seen that the areas of improvement were much larger than the areas of degradation during the study period. Among them, the areas of significant ESV degradation accounted for 17.19% of the total areas of the study area, and slight degradation accounted for 4.09%; the areas of slight ESV improvement accounted for 7.30%, and significant improvement accounted for 41.15%; and the areas of stable and unchanged ESV accounted for 30.27%.Fig. 5The trend of ESV in the study area, 1990–2020Full size imageTable 5 The areas and proportion of ESV change trends from 1990 to 2020Full size tableThe trend of ESV changes in the coal mining impact areasAs shown in Fig. 6, for the control areas, there were three turning points in 1997, 2005 and 2009, the APC (95% CI) corresponding to the four intervals were APC1990–1997 = 1.09 (95% CI:0.7 ~ 1.5, P P = 0.028), APC2005–2009 = 1.01 (95% CI:-0.3 ~ 2.3,
Add Comment