# Digitalization in Open-Pit Mining: A New Approach in Monitoring and Control of Rock Fragmentation
## 3 Experiments  
To prove the hypothesis, experiments were carried out in a granite (crushed stone) quarry in the Leningrad region of the Russian Federation. Four technological stages were used for the experiments--geological including the study of the rock structure, blasting stage, brommelling, and crushing at the factory.  
The geological stage of the experiment consisted of taking rock samples (samples were taken from three different areas of the rock massif, it allowed us to take into account the effect of heterogeneity) and further sample preparation--sawing and grinding, photographing samples using macroscopy against a measuring tape and counting the average grain size, evaluating the uniformity of grain structure, and evaluating grain fragment form by hand. Mineral resources are represented by igneous rocks--geniss granites and gneiss, which do not differ from each other in physical and mechanical properties and belong to a single technological type of raw materials--moderately fractured rocks of III-IV categories, with compressive strength from 77 to 276, on average 180-200 MPa; average volumetric weight--2.67 t/m\({}^{3}\). The strength coefficient according to [PERSON] [PERSON] scale is in the range of 12-16. Figure 4 shows several fragments of rock samples prepared for the experiment.  
The experiment at the blasting stage was conducted using the photoplanimetric method, piece-by-piece measurement of blasted rock mass pieces, and sieve analysis. It should be noted that such methods of experimentation were used because of the impossibility of using automated methods of visual control, etc. However, the experiments described in this paper can be performed using automatic control systems. These systems will make it possible to obtain significant experimental data and to more accurately determine parameters such as the average lump size and the distribution of rock fragmentation.  
As part of the experiment, photo-fixing of the area of rock mass breakdown at a distance of 6 m was carried out at the end of blasting (Figure 5). Red-and-white measuring tape was applied to the breakdown areas, with red-and-white strips alternating at 1 m intervals. The measuring tape was overlaid every 10 m. The measuring tape was necessary to determine the scale, and to measure and determine the form of the blasted rock mass pieces. Additionally, two samples were taken from two places of rock explosion (with a volume of 2 special vehicles--a Belaz dump truck). These samples were poured onto a specially prepared flat area. The fragment form was determined; each piece of the blasted  
Figure 4: Experimental rock samples.  
rock mass was measured and weighed. Additionally, the rock fragmentation was defined using special software and compared with the results obtained.  
The crushing and thrombelling stages were carried out manually in the same way as the blasting stage. Samples of material for the experiment were taken directly from the conveyor at three points--the beginning, middle and end of the belt--every hour during the entire shift. The volume of each sample to be taken was 1 linear meter.