New calculated unit use of explosives develops with the increase out of material hardness

New calculated unit use of explosives develops with the increase out of material hardness

Strategy based on appropriate lithology shipments

Undergoing stone blasting, the fresh new physical and you can mechanized qualities of your rock is actually seriously you to definitely of head affairs one to influence the result regarding rock blasting 21 . Discover often an unclear knowing that the brand new more challenging the fresh new rock, the new more challenging it’s is blasted in the present technology globe. Although not, the new blasting feeling is not just as requested into the systems strategies. Alternatively, it has been learned that this new hardness of rock isn’t high while the equipment use of explosives try higher twenty two .

According to the breaking device out of stone blasting 23 , the power released by explosives acts towards rocks because of the wonder revolution and you will expansion pressure of detonation fuel whenever an explosive explodes with the stones. The best exhaustion regarding stones is a result of the action worry produced by new rush exceeding its energy restrict, and therefore demonstrates that the fresh crushing state is closely pertaining to the brand new rush time together with technical characteristics of stone. Put another way, according to the specific conditions out-of tool explosive application mode, sort of, and you will 100 % free epidermis, the latest fees quantity is mainly dependent on the new mechanized properties off material to attain a particular smashing feeling. Ergo, the fresh new lithology distribution is regarded as the top cause for determining the newest equipment usage of explosives twenty four .

In an out in-breadth study of the new lithology out-of hard-rock, it is unearthed that large be concerned keeps a critical effect on the fresh blasting process and you will material cracking impact. The results along with show that large-web site be concerned handling and blasting loading aren’t two separate procedure, on the contrary, it works into the collaboration, as well as the active handling has actually a life threatening effect twenty-five . Hence, the latest shipment of hard rock is the vital thing to the framework out of an excellent segmented fees to possess blasthole.

Grouping of blasthole rock strata

Regarding the old-fashioned blasting processes, this new lithology variation across the great time opening depth is not believed on the blasting structure. Hence, a single charges construction are implemented. Regarding the superimposed material mass with soft and difficult inclusions, the weakened interlayer’s compressing and tensile opposition strength have become reasonable compared with one on the state-of-the-art material formations, nearly negligible. At the time, new poor interlayer can quickly end up being the flood station of the detonation gasoline and you may damage brand new smashing and you may organizing effect of this new high-tension gas generated by the fresh new explosion. In addition, in the case of large hard rock rather than explosion breaks, it is difficult to split sizeable stones utilizing the second smashing concept away from take off stone accident in the putting processes owed to a weak interlayer twenty-six . For this reason, this new division out-of soft rock and hard rock is an essential action in the design method.

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, Rs means the thickness of soft rock, and Rh means the thickness of hard rock.

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