TLS and SfM Approach for Bulk Density Determination of Excavated Heterogeneous Raw Materials

Abstract

A frequently recurring problem in the extraction of mineral resources (especially heterogeneous mineral resources) is the rapid operative determination of the extracted quantity of raw material in a surface quarry. This paper deals with testing and analyzing the possibility of using unconventional methods such as digital close-range photogrammetry and terrestrial laser scanning in the process of determining the bulk density of raw material under in situ conditions. A model example of a heterogeneous deposit is the perlite deposit Lehôtka pod Brehmi (Slovakia). Classical laboratory methods for determining bulk density were used to verify the results of the in situ method of bulk density determination. Two large-scale samples (probes) with an approximate volume of 7 m 3 and 9 m 3 were realized in situ. 6 point samples (LITH) were taken for laboratory determination. By terrestrial laser scanning (TLS) measurement from 2 scanning stations, point clouds with approximately 163,000/143,000 points were obtained for each probe. For Structure-from-Motion (SfM) photogrammetry, 49/55 images were acquired for both probes, with final point clouds containing approximately 155,000/141,000 points. Subsequently, the bulk densities of the bulk samples were determined by the calculation from in situ measurements by TLS and SfM photogrammetry. Comparison of results of the field in situ measurements (1841 kg·m −3 ) and laboratory measurements (1756 kg·m −3 ) showed only a 4.5% difference in results between the two methods for determining the density of heterogeneous raw materials, confirming the accuracy of the used in situ methods. For the determination of the loosening coefficient, the material from both large-scale samples was transferred on a horizontal surface. Their volumes were determined by TLS. The loosening coefficient for the raw material of 1.38 was calculated from the resulting values.

Different Paths for Developing Terrestrial LiDAR Data for Comparative Analyses of Topographic Surface Changes

“…Therefore, this last DTM was characterized by a much larger total number of points equal to 70,071,395 as well as a higher average point density for the AoI at 437 pt/m 2 (Table 1). The analysis of surface differences carried out with the use of GCD software [12,14] made it possible to estimate the physical parameters of the gravel-cobble deposit, which was the result of errors in the CSF algorithm classification. The results of the DEMs comparison from 2010 show negligible differences between both methods of classifying the ground points ( Figure 4; Table 2).…”

“…In this context, a significant part of the research is focused on estimating the cubature or bulk density of the raw material under in situ conditions, all of the while using conventional and modern remote sensing methods such as digital close-range photogrammetry (structure from motion (SfM) photogrammetry) and terrestrial laser scanning. These works usually document relatively small (about 5%) differences between the parameters determined in a laboratory and those under field conditions by TLS [12]. This is all the more so because during the extraction or movement of the sediment resulting from natural processes (landslides, mud and rubble run-off, debris flow, etc.…”

“…Kociuba [36] also pointed to a 6% growth of volume material that was deposited in a small alluvial fan that developed directly below a rill and suggested that this was due to the loosening of the transported material as well as multiple stages of aggradation (multilayer deposition on the cone). In fact, the loosening coefficient for the heterogeneous mineral resources of the perlite deposits was estimated to be 1.38 [12].…”

“…On the contrary, data from terrestrial laser scanning (TLS) with densities that range from several dozen to several hundred or even several thousand pt/m 2 are used to inventory larger-scale resources such as quarries, gravel pits, sandpits [12] and areas that do not exceed 1 km 2 [3,4]. High resolution TLS data can be used to estimate the volume of mineral deposits in order to determine the quantitative potential.…”

Suitability of Aerial Photogrammetry for Dump Documentation and Volume Determination in Large Areas

“…TLS measurement can be used in an industrial environment to document industrial machinery, such as rotary kilns [12] and boiler drums [13]. Another use is the ability to accurately determine the volumes of mined reserves and determine the specific gravity of heterogeneous materials [14].…”