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Deep-hole blasting and chamber blasting technology are widely used in mining and large-scale earth-rock excavation or ... It is observed that when the distance …
The suggested safety distance in deep mining. ... (about 16 times the radius of the blast hole); the designed safety distance is not enough to reduce the influenced area; therefore, the safety distance in −780 m and −1020 m are suggested to be 1.2 m and 0.8 m, respectively, that can effectively reduce influenced area of hoop …
oitted to Ecellence in Mining Safety Last Modified: Page: JAN 2013 2 of 21 MODULE 12 (C ONT.)Surface Blasting Safety Procedures Blasting Materials Surface delays, detonators or blasting caps, boosters, safety fuse, down-line and other explosives used for blasting.
After deep-hole blasting, the energy of small mine tremors increases by an order of magnitude (10 4 J), but large-energy mine tremors above 5 × 10 5 J are basically eliminated. In addition, the mine tremors after deep-hole blasting do not cause dynamic …
Large blast holes may be as large as 9 inches or 225 mm. in diameter, while small holes may be as small as 1.5 inches or 38 mm. in diameter. Hole orientation is influenced by project topography, excavation boundary geometry, bench height, bench access, and many other factors. Equipment limitations will also influence hole orientations.
4.0 The entire operations of conduct of safe deep-hole drilling and blasting operations in the mine including transport of the explosive to the site of its use, shall be …
The grand-scale suspended roofs overlying the goaf are commonly developed under thick-hard rock strata (THRS) during the mining process of the deep …
Schematic Diagram of Step Elements for Open-Air Deep Hole Blasting Note: In the figure, H is the height of the step; W1 is the chassis resistance line of the front row cannon holes; L is the drilling depth; L1 is the length of the medicine; L2 is the blockage length; Pole distance; B is the row distance; B is the safe distance from the …
The results provide theoretical and practical guidance for predicting safety in similar deep tunnels during blasting. ... is smaller than that in cutting holes. When the distance from blasting ...
The grand-scale suspended roofs overlying the goaf are commonly developed under thick-hard rock strata (THRS) during the mining process of the deep coal seam. As a result, strong mine seismicities triggered constantly by deep mining have impeded severely the safety and efficient operation of deep mines. The working-face …
Presplit blasting Spacing = Hole diameter x 12 Burden = 0.5 x production blast burden (B) Uncharged length at top = 10 x D Powder factor = 0.5kg per square metre of face Do not stem holes. Fire all holes on the same delay, or in groups of ≥ 5 holes Smooth blasting Spacing = 15 x Hole diameter (hard rock) 20 x Hole diameter (soft rock)
To address the problems with deep-hole presplit blasting intended to fracture and improve the permeability of deeply buried, soft, high-gas-content coal seams, a method using a blasthole and a ...
Deep-hole blasting and chamber blasting technology are widely used in mining and large-scale earth-rock excavation or ... It is observed that when the distance between millisecond blasting holes is equal to greater than 5 m, the detection signals between holes will not interfere with each other. ... and also provides a basis for the …
Deep hole blasting diameter was 40 mm; therefore, designed charge diameter was 32 mm and charge length was 1 m. ... A total of 6 pairs of cutting holes were arranged. The distance between the ...
blasting operations with a short distance [2]. ... Under instantaneous detonation of deep hole blasting, blasting ... The use of low-explosion industrial explosive and uncoupled segmented charge can reduce the impact of blasting on slope safety. Due to the existence of a large number of joints and fissures in the
The aperture of the open-pit deep hole blasting is largely related to the type of drilling rig. In the blasting area considered in this study, the aperture was 90 mm. ... The chassis resistance line was calculated considering the safety conditions of drilling operations as follows: W 1 ... The considered unit was located at a certain distance ...
Guo et al. 22,23 studied the influence of blasting hole spacing, the distance between blasting hole and extraction hole, and the distance from blasting hole to roof and floor of the coal seam on ...
Deep-hole blasting and chamber blasting technology are widely used in mining and large-scale earth-rock excavation or landfill projects, due to their advantages of high efficiency and low cost.
The No. 2 rock emulsion explosive is used for the on-site blasting, the density of the explosive is 1.24 g/cm 3, the detonation speed is D = 4200 m/s, the …
Deep hole blasting Deep hole blasting is the blasting method that uses drilling equipment to drill deeper holes as the charge space of mining explosives. The deep hole blasting in open pit mine is mainly bench blasting. Deep hole blasting is a kind of blasting method which is widely used in open pit mine. The depth of the blast hole is …
Once the blast holes are triggered, the blast wave expands in a cylindrical shape, exerting pressure on the water as it travels . This wave then forcefully hits the nearby rock's surface through the thin layer of water, causing the disintegration of the rocks' intergranular structure at some distance from the blast hole [7, 21, 22].
The results provide theoretical and practical guidance for predicting safety in similar deep tunnels during blasting. ... is smaller than that in cutting holes. When …
Abstract Numerical simulations were performed using a 2D particle flow code (PFC2D) to study the dynamic behavior of two deep buried tunnels subjected to blasting disturbance. Depending on the distances between the two tunnels and blasthole, the two tunnels were divided into adjacent tunnels and nonadjacent tunnels, respectively. The propagation …
DOI: 10.1016/J.TUST.2021.103866 Corpus ID: 233582894; A study on hollow effect and safety design of deep crossing caverns under blasting vibration @article{Xu2021ASO, title={A study on hollow effect and safety design of deep crossing caverns under blasting vibration}, author={Mingnan Xu and Xinping Li and Tingting Liu and Yi Luo and Huang …
helps to ensure the safety of the concerned structures as well as ... sensitivity analysis that distance from the site of blast, number of ... Anurag Agrawal . Blast Design for …
A 2D FEM model is prepared in Rocscience based on the geotechnical report just beside the blasting holes to cross-check the effect of blast-induced vibration on the surrounding slope of the rock excavation inside the station box. Rock properties for the present model are in Table 6.
The influence radius of single-hole blasting was 3.1 m, the hole diameter of double-hole blasting was 113 mm, the hole spacing was 5.5 m, and the delayed blasting time was 25 ms.
For deep hole blasting, the original oblique hole cutting method necessitates the explosive to be concentrated at the bottom of the blast hole, making the distribution of the explosive energy unreasonable. ... The distance between the center hole and the face ZY is 250 mm, the length of the charge is 1.21875 m, and the length of the …