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On a long wall face, the shot holes are drilled at an angle of 45° to 60° to the face; a coal face 2.4 m high requires 3 rows of shot holes and distance of holes in the same in the same row should be nearly 1.2 m. Powder factor with solid blasting is 1.5 to 2.5 te of coal per kg of explosive and 0.8 to 1.25 te of coal per detonator.
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(A) The blast depth in the initial excavation must be limited to the elevation of the top of the pipeline, plus one-half (1/2) of the distance from the nearest blast hole to the pipeline; (B) …
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Request PDF | Safety distance for secondary shotcrete subjected to blasting vibration in Jinping-II deep-buried tunnels | Performance and quality of secondary shotcrete is vital to the stability ...
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Depth and Pattern of Blast Holes: The depth of vertical blast holes in coal is generally equal to the height of the bench. In hard rock like sandstone, laterite, hematite, etc. the depth should be 0.5 …
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Prediction of Fan-Shaped Deep Hole Blasting in Sanxin Gold and Copper Mine. Minerals 2022, 12, 788.https:// ... likely to cause the top and bottom plate of the underground to become loose causing safety hazards. ... were conducted to determine the optimal blasting parameters including hole distance, explosive unit consumption, and row space. ...
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Misfire is the hidden danger in open deep-hole blasting and usually undiscovered.In order to control misfire and accidents,various emergence causes and damages of misfire were analyzed,and the treatments and preventive measures were proposed.In process of blasting engineering,strengthening post training,perfecting site management system,optimizing blasting …
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explosive, pointed out that deep hole blasting can be used in vertical shaft construction of frozen hard rock section [12]. Dey et al. pointed out that cutting forms of vertical shaft deep hole blasting are parallel cylindrical cutting and inclined tapered cutting, use deep hole blasting can increase the driving speed vertical shaft [13].
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A review of prior studies underscores the importance of directional crack penetration in achieving effective tunnel blasting [28], [29].Although researchers have gained further understanding from the perspective of crack extension dynamics, there remains a relative scarcity of studies on the crack propagation law under multi-hole shaped charge blasting, as well as a …
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After statistical analysis, due to the supplemental blasting of the central hole, the average blasting footage was increased by 0.35 m, and the average specific charge was reduced by 0.43 kg·m− ...
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the case of nine-hole cut blasting without considering empty holes, there is only one free surface in the lower chamber, which is insucient. Therefore, it is necessary to set empty holes. The function of the empty hole is to provide enough free surface and release space for the rst round of charge holes and subsequent blasting.
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The results show that using large diameter empty hole blasting technology in vertical shaft construction of frozen hard rock section can significantly improve the speed of vertical shaft ...
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The Datong Mine was a background to study the blast crush zone and drainage influence range following deep-hole blasting with holes laid in coal seams, which resulted in a 24% increase in gas flow ...
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The calculation model is used only for the calculation of relevant parameters of empty hole distance nearest blast hole. Other charges can determine the optimal resistance according to the actual blasting free surface width. ... Security of freezing pipe safety measures. In a deep hole blasting of vertical shaft frozen soil, the effect of ...
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Surface Blasting Safety Procedures Blasting Materials Surface delays, detonators or blasting caps, boosters, safety fuse, down-line and other explosives used for blasting. Blast Site The area explosive materials are handled during loading that includes a 30 foot perimeter around the loaded blast holes. This perimeter must be demarcated with signs
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The Collaborative Innovation Center of Coal Safety Production of Henan, Henan Polytechnic ... coal body firmness coefficient and coal seam gas pressure positively affect the penetration enhancement of coal seam deep-hole blasting. ... To study the influence of the distance from a control hole to a blasting hole on fractures' evolution laws ...
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Control the number of blasting holes and unit detonating charge over equal segments of fuse and detonating cord, reduce the impact of close-range blasting vibration of vertical deep holes on fixed ...
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Personnel should be trained in blasting safety, wear appropriate personal protective equipment, follow established procedures and safe work practices, be in communication with the blast operator, and be informed of …
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Many factors affect the perception of the sound of blasting. The sound depends on your distance from the blast, the amounts and types of explosives used per hole, the depth of the charges, the type of cover used, and so on. When blasting, sharp reports may be heard, as well as loud and/or low rolling rapid fire rumblings. Regulatory limits are based on a scale related to air pressure …
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Due to the high in situ stress of the deep rock mass and the restraining effect of the surrounding rock, the deep hole blasting of vertical shaft faces the problems of low borehole utilization rate and poor blasting effect. In this regard, this paper proposes a deep hole multi-stage cut blasting technology of vertical shaft. Preliminary engineering practice shows that such cut …
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Blasting operation is primarily used to fragment and break up rocks, facilitating excavation and extraction of valuable minerals (Bui et al. 2021).This operation in surface mines can have both undesirable and desired effects, depending on various factors and the specific objectives of the mining operation (Bhandari, 1997).The desired effect of blasting is to create …
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7.0 No drill or bore rod or pick shall be inserted in butts of old deep holes even if an examination has failed to reveal presence of explosives. 8.0 Drilling operations shall not be …
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The Effect of Blast-Hole Arrangement, Delay Time, and Decoupling Charge on Rock Damage and Vibration Attenuation in Multihole Blasting January 2022 Shock and Vibration 2022(8):1-18
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Formulas and best practices. Below are practical formulas and tips that can be used to calculate particle size and stemming height. 1. The particle size should be such that it can effectively fill the void spaces in the blast hole and provide …
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Blast Design for Controlling Some of Environmental Nuisances during Deep Hole Blasting in 0031 Surface Overburden Benches. Insights Min Sci technol. 2019; 1(2): 555557. DOI: 10.19080/IMST.2019.01.555557 blasting with Nonel initiation system than an electronic initiation system [11]. Data evaluation is not solely based on peak particle
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When the spacing between holes is 1 m, the blasting effect is optimal, with a single hole effectively reaching a cutting seam length of about 0.5 m. There are obvious through cracks in the cave ...
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Powerlines and portable electric cables for equipment being used shall be kept a safe distance from explosives or blasting agents being loaded into drill holes. Cables in the proximity of the blast area shall be deenergized and locked out by the blaster.
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After a hole is "sprung" ample time must be left for the hole to cool before further loading or placing of explosives or blasting accessories takes place. [Amended by B.C. Reg. 207/2021, …
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How far does the fragmentation extend from the blasthole? Small blastholes are usually drilled from 6 to 15 feet apart and large blastholes may range up to 30 feet apart.
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To investigate the impact of deep-hole pre-splitting blasting on gas extraction flow rate, we constructed one blasting hole and four exploratory holes at distances of 2 m, 2.5 m, 3.0 m, and 3.5 m from the blasting hole in the bottom pumping lane …
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The traditional cut blasting method involves establishing an empty hole in the center of a circle of cut holes. During the cut blasting process, the rock mass is broken under the effect of stress wave propagation, and high-pressure gas evenly flows into the broken rock to form a gas-solid mixture, which is thrown from the cut cavity longitudinally due to the volume expansion of …
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