JP3262859B2 - Blasting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blasting method.

[0002]

2. Description of the Related Art It has been empirically known that, when crushing rock during blasting operation, detonating an explosive with an MS electric detonator produces less large lumps than detonating an explosive with an instantaneous detonator. ing. It has been thought that the rocks will be finer due to the increased free surface and the collision of the rocks exploded by the explosives, as they are sequentially detonated.

Further, U.S. Pat. S. Bureau of Mi
According to the study of nes, in order to improve the crushing effect in blasting the bench, the time difference between the holes per second was 1 m,
It is desirable to set it to 3.3 to 10 ms. The experiment was performed by changing the particle size of the rock and the difference in the detonation time between the holes by using a combination of a step blaster and a ground search primer when blasting the bench. At the same time, the pressure of the gas generated by the explosion of the explosive was also measured. From the above results, when the pressure of the gas generated by the explosion of the first hole reached the second hole, the explosion of the explosive in the first hole It is considered that the rock near the second hole is compressed by the pressure of the gas generated by this, and at that time, the explosive in the second hole is detonated, so that the force of the explosive is effectively applied to the bedrock.

[0004] Similarly, as an empirical blast design method, a method of expressing an optimum second time interval by a product of a coefficient and a hole interval is generally referred to.
3-5 according to ting, 3.3 according to Dupont
１６16.7, according to Nitro Nobel 5-10
Has been optimized.

[0005]

However, in the conventional MS electric detonator and the DS electric detonator using the postponed medicine, there is a limit to the granularity control because of the accuracy of the seconds and the delay time. was there. Also, depending on the empirical blast design method, each coefficient has a range and each researcher also has a difference.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have focused on the action speed of gas pressure in the rock to improve the blasting effect. The explosive detonation time is determined by dividing the hole interval by the action speed of the gas pressure, and the blast design is performed. For example, Japanese Patent Application Laid-Open No. 57-142 describes
Using those disclosed in Japanese Patent Application Publication No. 498 and Japanese Patent Application Laid-Open No. 58-83200 , a blasting method utilizing the arbitrariness of these delay times and high second time accuracy was successfully achieved.

That is, the present invention provides a plurality of blasting operations.
In the blasting method in which the blast holes are sequentially detonated,
Measured elastic wave velocity of 10 in rock mass with pre-measured hole spacing
Determined by dividing by the action speed of the gas pressure obtained as ~ 15%
It is characterized by firing sequentially according to the firing time interval
Blasting method, and the explosive detonation time interval
As a means to ensure the accuracy, high-speed precision electrical delay lightning
The blasting method is characterized in that the blasting is performed using a tube .

[0008]

In the blasting operation, the interval between blast holes is 2 to 10 m, the elastic wave velocity in the rock is 500 to 6000 m / s, and the gas pressure is 12% of the elastic wave velocity. Action speed is 60-720m / s
Becomes Therefore, the time during which the gas pressure generated from the first blast hole acts on the second blast hole is 3 to 167 of the first blast hole.
ms. When this gas pressure is acting on the rock near the second hole, it explodes the explosive in the second hole. In this way, the gas pressure is applied to the blast holes sequentially, and the rocks near the blast holes can be blasted while being compressed.

[0009]

EXAMPLES The blasting method of the present invention will be described below in detail with reference to examples.

Example 1 In a quarry with a bench height of 7.5 m, a hole diameter of 65 mm was used.
Bench blast was performed with φ, hole length 8.5 m, hole interval 2.5 m, resistance wire 2.5 m.

First, prior to the blasting, the elastic wave velocity of the rock was measured in order to determine the detonation time of the electric delay electric detonator with high time accuracy. For the measurement, a three-point vibrometer was installed at 10 m intervals, the rock was vibrated by a heavy machine, the vibration between the three points was measured, and the elastic wave velocity was obtained. As a result, it was found that the bedrock of this crushed stone factory had an elastic wave velocity of about 2100 m / s. From this result, the action speed of the gas pressure is about 2
Since it is 52 m / s (a value calculated assuming 12% of the elastic wave velocity), the explosion time is 9.9 ms. Therefore, as an example of the present invention, a firing time difference of 10 ms per hole was set.

[0012] Subsequently, on the basis of the seconds when the design results, especially
JP-A-57-142498 and JP-A-58-8320.
High sec when accuracy electrical delay electric detonator shown in 0 JP dynamite 10 equipped with a (10 ms 1 to 15 stages)
Using 0 g as the parent die, per 15 holes in the bench hole, A
After loading 15 kg of NFO explosive and charging, after blasting,
Table 1 shows the number of rocks that require breaker treatment, the breaker treatment time, the number of subdivided blasts, and the number of days of rock treatment.

Comparative Example 1 On the same bench as in the example, explosives were all detonated with an instantaneous electric detonator, and the same items as in the example after the blast were measured and compared. Table 1 shows the results.

COMPARATIVE EXAMPLE 2 Explosives were detonated on the same bench as in Examples and Comparative Example 1 using an MS electric detonator (25 ms, 1 to 15 steps) using a postponed explosive. Were measured and compared. Table 1 shows the results.

Comparative Example 3 On the same bench as in Example and Comparative Example 1, explosives were detonated by a DS electric detonator (250 ms, 1 to 15 steps) using a delaying agent in the same manner as in the Example after the explosion. Were measured and compared. Table 1 shows the results.

[0016]

[Table 1]

As described above, according to the present invention, it is possible to reduce the number of rocks requiring breaker processing after blasting, the breaker processing time, the number of small blasts, and the number of days for processing rocks. This can improve the effect of rock crushing by blasting.

[0018]

According to the blasting method of the present invention, blasting can be performed on rocks which have been successively compressed by the gas pressure caused by the blasting of the preceding stage. It is possible to improve the crushing effect of rocks,
It is possible to reduce the time required for the subdivision work in the crushing of crushed stones and to improve the work efficiency.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-302600 (JP, A) JP-A-1-285800 (JP, A) JP-A-62-261900 (JP, A) 1846 (JP, B1) JP 40-20720 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F42D 1/06 F42D 3/04

Claims (2)

(57) [Claims] 1. A plurality of blast holes are sequentially generated by a blasting operation .
In explosive blasting method, outline the hole spacing between each blasting hole.
As 10-15% of the elastic wave velocity in rock mass measured earlier
Detonation time determined by the operating speed of the resulting gas pressure
A blasting method characterized by firing sequentially according to the interval . 2. The blasting method according to claim 1, wherein the explosive is detonated using a high-precision electric delay electric detonator as a means for securing an explosive detonation time interval.