Energy components in rock blasting

Sanchidrián, José A.; Segarra, Pablo; López, Lina M.

doi:10.1016/j.ijrmms.2006.05.002

Cited by 163 publications

(67 citation statements)

References 10 publications

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“…The population of the total explosive energy in each hole is also represented in Fig. 2; the energy of the explosives rated as heat of explosion at full detonation regime is 4090 kJ/ kg for gelatin and 3893 kJ/kg for ANFO (Sanchidrián et al 2007). The distributions of energy across the blast are more uniform than the distributions of masses, which should result in limited variations in the fragmentation within the blast, over which the mean powder factor in each blast prevails, hence the sensitiveness of fragment sizes to it.…”

Section: The Blastsmentioning

confidence: 99%

The Fragmentation Energy-Fan Model in Quarry Blasts

et al. 2018

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This paper investigates fragmentation in an aggregate quarry in the light of the fragmentation-energy fan concept. Six blasts were monitored, located one behind the other in the same quarry area. The rock structure was blocky, the water level and the usage of explosives were variable within and between the blasts; however, the distribution of explosive energy in the blocks was relatively uniform and the performance of both explosives per unit mass appeared to be similar. The powder factor above grade was between 0.28 and 0.44 kg/m 3 . Fragmentation of the plant feed was measured using an online digital image analysis system and three belt scales in the crushing plant. The oversize material that was not directly fed to the plant after the blast corresponds to 3-9.3% of the total. Data from image analysis was used to build the size distribution in the coarse range (fragments above 120 mm), and the passing fractions at 120 and 25 mm obtained from belt scales data were used in the range 120-25 mm. The non-dimensional percentile sizes between 10 and 90% for each blast are described through power functions of the powder factor above grade; the model coefficients (i.e. nine prefactors and nine exponents) are statistically significant. From them, using the principles of the fragmentation-energy fan and the Swebrec distribution properties, the fragmentation can be expressed in terms of the powder factor by means of five parameters: the fan focus coordinates and the three parameters of a function of the exponents versus the percentage passing. The model shows a good capability to describe fragmentation from 10 to 90 percentile sizes, with an expected error below 6% and a maximum likely error less than 15%.

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Section: The Blastsmentioning

confidence: 99%

The Fragmentation Energy-Fan Model in Quarry Blasts

et al. 2018

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“…In shallow-hole blasting, the detonation of explosives creates shallow cracks in the hanging wall and tensile stress then arise from these cracks during bending induce hanging wall fracture. In contrast, DHB directly uses explosion to fracture hanging wall and reduce the energy it accumulates [39,40]. Given the total thickness of the hanging wall-1 and hanging wall-2 over the 43# seam was 64.1 m, the blasting holes should be longer than 5 …”

Section: Mechanism Of Pressure Relief By Dhbmentioning

confidence: 99%

Hanging Wall Pressure Relief Mechanism of Horizontal Section Top-Coal Caving Face and Its Application—A Case Study of the Urumqi Coalfield, China

Guo

Wang

et al. 2017

Energies

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Abundant steeply-dipping thick coal seams (SDTCS) have been found in Xinjiang, China, and they are mined largely by the horizontal section top-coal caving (HSTCC) method. The hanging wall of the HSTCC face is nearly vertical and does not fracture easily after the underlying coal is extracted. As a result, stress tends to concentrate in the hanging wall of the lower-section working face (LSWF) and then induce dynamic disasters. In this study, a mechanical model of a HSTCC face's hanging wall in steeply-dipping seams was constructed to study the characteristics of hanging wall deformation. The mechanism of hanging wall pressure relief by deep-hole blasting (DHB) was analyzed and the effectiveness of DHB was investigated by simulation using the LS-DYNA software. Based on these studies, parameters relevant to pressure relief by DHB were determined and then DHB was applied to the 4301 working face in the Jiangou coal mine. The results show that the average pressure of measured at the 4301 working face decreased about 34% from those at the 4501 face where the hanging wall was not blasted. Accidents related to dynamic rock pressure, such as support crushing and large-scale rib fall, did not occur at the 4301 working face throughout the mining process. Additionally, in order to constrain the surface "V"-shaped collapsed grooves induced by repeated mining of HSTCC faces and prevent the subsequent failure of the surrounding rock on the sides of the collapsed grooves, loess was used to fill in the grooves to provide constraint and dynamic control on the surrounding rock. The two complementary technologies proposed in this study provide a guide on how to control hanging wall of SDTCS in similar conditions.

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“…Energy passing through rock mass in the form of seismic waves is seismic energy. [16] suggested the following formula to estimate the seismic energy. The authors have proposed another concept in estimating energy by analyzing the complete wave forms obtained from ground vibration monitoring.…”

Section: Seismic Energymentioning

confidence: 99%

A New Method of Estimating Wave Energy from Ground Vibrations

Chandar¹,

Sastry²

2015

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Performance of explosive energy is rated in a number of ways, obtained either from theoretical calculations or from experimental tests. However, it is difficult to determine the amount of the explosive energy transferred to the rock and converted into efficient work in the application of rock blasting. Although measurement of some of the effects of explosive energy in rock mass is ground vibration, noise, etc., which are usually conducted for blast control/analysis purpose, the results are rarely used on energy content. Energy transferred to the rock in the form of seismic waves is called seismic energy. In conventional analysis of blast results, generally, the ground vibrations generated due to blasting operations are monitored at a known distance from blast site with a geophone/ground vibration monitor, in three mutually orthogonal directions. Using such wave forms, an energy component is estimated from all the wave forms in three directions, using a sophisticated signal processing software, which is termed as "wave energy". The wave energy is compared with the estimated seismic energy. An investigating program was taken up involving 31 blasts conducted at a hard rock excavation site to assess the influence of depth of excavation and scaled distance on the seismic energy wasted in the form of ground vibrations.

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Energy components in rock blasting

Cited by 163 publications

References 10 publications

The Fragmentation Energy-Fan Model in Quarry Blasts

The Fragmentation Energy-Fan Model in Quarry Blasts

Hanging Wall Pressure Relief Mechanism of Horizontal Section Top-Coal Caving Face and Its Application—A Case Study of the Urumqi Coalfield, China

A New Method of Estimating Wave Energy from Ground Vibrations

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