Strategy considering real lithology shipments

Undergoing material blasting, the brand new actual and you will mechanized attributes of the stone is actually absolutely one to of chief items that determine the outcome regarding rock blasting 21 . There’s have a tendency to an unclear realizing that the new more challenging the brand new stone, the fresh harder it’s as blasted in today’s systems globe. Yet not, the fresh new blasting perception isn’t just as expected into the technology methods. Instead, it was unearthed that this new hardness out of stone is not large because the unit consumption of explosives was highest 22 .

Depending on the breaking process out of stone blasting 23 , the energy released because of the explosives serves toward stones from the amaze trend and you can expansion stress from detonation energy when an explosive explodes to your rocks. The greatest depletion out-of stones is a result of the action stress escort San Diego created by the latest rush exceeding its fuel limit, and therefore implies that the newest smashing state are directly connected with this new explosion times therefore the mechanical services of rock. Put another way, underneath the certain requirements regarding product explosive use mode, type, and you can totally free skin, new costs amounts is mostly influenced by this new mechanical services off stone to attain a particular crushing effect. For this reason, the latest lithology shipments is regarded as the primary reason behind deciding the brand new device use of explosives 24 .

Inside an in-breadth study of this new lithology out-of hard-rock, it’s learned that highest stress provides a critical effect on new blasting processes and you can material cracking impression. The outcome including reveal that large-webpages worry handling and you may blasting packing commonly a couple of independent procedure, to the contrary, they work from inside the cooperation, plus the vibrant unloading has a significant effect 25 . For this reason, the fresh shipping away from hard-rock is key on the construction out of a great segmented charge to own blasthole.

Group of blasthole stone strata

Regarding the antique blasting processes, the lithology variation across the great time gap depth isn’t considered on blasting design. Ergo, an individual fees framework is accompanied. About layered material mass with silky and hard inclusions, the fresh weak interlayer’s compressing and tensile resistance power are lower in contrast to that in the state-of-the-art material formations, nearly negligible. At the time, the brand new weakened interlayer can quickly get to be the flood channel of your detonation gas and you will damage the latest smashing and you may throwing effect of the new high-pressure fuel from this new burst. As well, when it comes to high hard rock in place of rush fractures, it is challenging to break considerable stones utilizing the secondary smashing principle out of cut-off stone collision regarding the tossing techniques owed to help you a failure interlayer twenty-six . Ergo, the fresh new office from soft-rock and hard stone is a vital step from the structure means.

The lithology data of the corresponding blastholes are obtained by intelligent drilling rigs. According to the hardness of the lithology, the blasthole rock strata are divided into 7 categories, and lithology classification numbers range from Type 1 to Type 7 27 . In order to facilitate the design and calculation of blasthole charge structure, the adjacent strata with similar lithology are combined and grouped. The lithology is divided into two groups of soft rock and hard rock, denoted as \(s\) and \(h\) , respectively. The classification rule of soft rock and hard rock is that the strata numbered 1, 2, 3, and 4 are soft rocks, and rock strata numbered 5, 6, and 7 are hard rocks. The grouping diagram of blasthole rock strata is shown in Fig. 4: H refers to the blasthole depth, R_s means the thickness of soft rock, and R_h means the thickness of hard rock.