| Use of digital photogrammetry instead of GPS/laser survey techniques for cast blast monitoring in an operating coal mine was assessed. Photographs were taken before and after six cast blasts at the Highvale coal mine. Conventional surveying methods are typically limited to measuring coordinates of less than 100 points. The photogrammetric approach, under optimal field conditions, can measure hundreds of thousands of points resulting in higher spatial resolution and more accurate volumes. The fieldwork effort, area coverage of each digital terrain model, and the model accuracy are documented. Recommendations for optimal camera position and image acquisition mode to minimize fieldwork and to maximize areal coverage are given. Practical limitations and operational challenges involved with using the photogrammetry are discussed. Cast blast efficiency is calculated from the percentage of the blasted overburden volume thrown into its final position. The results were verified and compared with traditional surveying using cross section analysis. |
