Strategy according to specific lithology shipping
Undergoing stone blasting, the fresh physical and technical qualities of stone was positively one to of one’s head things that influence the effect from stone blasting 21 . You will find have a tendency to a vague knowing that this new more difficult the material, new more difficult it’s as blasted in the present technologies business. Yet not, the newest blasting impression isn’t just as questioned during the technologies strategies. Instead, it’s been discovered that the newest hardness off rock isn’t high since the unit consumption of explosives is higher twenty-two .
With respect to the breaking mechanism out of rock blasting 23 , the energy create of the explosives serves toward stones by wonder wave and you may expansion pressure off detonation energy whenever an explosive explodes for the stones. The greatest depletion out-of rocks is due to the action worry produced by the newest burst surpassing its fuel limitation, which demonstrates that the smashing condition is actually directly linked to brand new burst time and technical qualities of your own rock. To put it differently, underneath the specific requirements off product volatile application setting, types of, and free surface, this new charge number is certainly caused by dependent on this new mechanical qualities away from material to get to a certain smashing feeling. Ergo, brand new lithology shipment is definitely the number 1 reason for choosing new equipment usage of explosives 24 .
From inside the a call at-depth examination of the new lithology out-of hard rock, it’s found that higher worry has a life threatening effect on the brand new blasting techniques and material breaking effect. The results plus demonstrate that large-website stress handling and you may blasting packing aren’t several separate procedure, on the contrary, they work within the cooperation, therefore the dynamic handling have a critical impact twenty-five . Ergo, brand new shipments of hard rock is paramount towards the design regarding an excellent segmented costs for blasthole.
Collection from blasthole rock strata
From the old-fashioned blasting processes, the fresh new lithology variation across the blast gap depth is not considered regarding the blasting structure. For this reason, just one charge design was accompanied. Throughout the superimposed stone bulk which have flaccid and hard inclusions, the brand new weakened interlayer’s compression and you may tensile opposition electricity are particularly low compared with one on advanced stone formations, nearly negligible. At the time, this new weak interlayer can easily end up being the flood station of http://datingranking.net/japan-dating/ the detonation gasoline and you will damage the fresh smashing and you can organizing aftereffect of the high-pressure gas made by the rush. In addition, when it comes to higher hard-rock in place of burst cracks, it is difficult to crack significant stones utilising the second crushing concept regarding cut off material accident about organizing techniques due to help you a deep failing interlayer twenty-six . Therefore, the newest department from soft-rock and difficult stone is an essential action regarding the build strategy.
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.