Slope length of the reclaimed surface is another parameter that falls under regulatory permit. (VIP 9) The inspector can use measurement tools in a GIS to compare the length of a regraded slope on the DSM and compare the results to the length of the proposed slope specified in the permit.
After reclamation, slopes should be a uniform, or smooth shape. Concave slopes may retain too much water and not drain properly. Convex slopes may cause water to run off the slope causing erosion issues.
Of the fifteen VIPs that were tested, all could be accomplished using remote sensing and GIS techniques to support the inspection process with the exception of VIP 12 – Impounding Structures Identification. There was partial success with VIP 12 in that the impounding structures can be identified and measured with imagery. But at this time, these are the only reliable applications that can be conducted for impoundments. The following is a summary of the results for each VIP:
The mission of the Office of Surface Mining (OSM) is to carry out the requirements of the Surface Mining Control and Reclamation Act (SMCRA) in cooperation with States and Tribes. A primary objective of SMCRA is to ensure that coal mines are operated in a manner that protects citizens and the environment during mining, and to ensure the land is restored to beneficial use following mining activities. To support this mission, active and inactive surface coal mining and reclamation operations are inspected on a routine basis to ensure compliance with approved permits.
Satellite imagery provides a relatively inexpensive tool to monitor and assess vegetation regrowth over time, and thus, was identified as an added benefit to the VIP method.
With supporting field work, satellite imagery is ideal for mapping vegetation community types for large areas. As in vegetation cover mapping, image classification techniques can be used to extract vegetation community types and was identified as an added benefit to the VIP method. The figure below shows four community types: Pinon-Juniper Woodland (green), Mine Disturbance (yellow), Sagebrush (blue) and a general Revegetated Plot category (red) for the McKinley mine site. Most vegetation types can be identified and evaluated against revegetation success standards identified in the per
Satellite imagery has long been used to derive vegetation cover. With supporting field sampling, vegetation density (VIP 15) can be classified using the supervised image classification techniques. This is especially useful where the vegetation regrowth covers extensive areas making field surveys too time consuming and expensive. The figure below shows the result of a vegetation classification over a revegetated area at the McKinley mine site. Given adequate field sampling, these categories can be expressed in terms of percent cover as well. Three cover density categories were mapped a
Vegetation establishment (VIP 14) can be determined using multispectral satellite imagery and image processing software to compute the Normalized Difference Vegetation Index (NDVI). NDVI is a measure of the amount and vigor of vegetation growth and these images are developed to more easily distinguish green vegetation from bare soils.
Volumetric measurements are used to determine the level of compliance with respect to SMCRA regulations that require mines to restore topography to AOC, and determine the volume of topsoil piles to ensure that there is enough suitable topsoil to cover the regraded mine site. Volumetric calculations can also be used to determine the amount of bond to post prior to beginning operations. (VIP 10) Volumetric measurements on an open pit can quantify the amount of fill material needed to meet the regrade plan. Volumes related to pre and post mining topography are calculated. .
Water diversions are constructed to prevent and control water runoff and erosion problems associated with the disturbed area. Water diversions constructed on mine sites must be the same in terms of placement and size as identified in the permit requirements. (VIP 3) Using orthorectified satellite imagery in a GIS, the inspector can determine if water diversions have the correct location, length, and in rare cases, width as specified in the permit.