SU1765685A1 - Ore stepped excavation by blasting operation - Google Patents

Abstract

Use: mining industry. SUMMARY OF THE INVENTION: Prior to charging wells on an exploding ledge, the depth of the broken layer during the previous ledge of the rock layer hc is determined, and the tamping value is determined from the expression Ssab 2hc-hn, where 3ab is the tamping value, m; hc - value of the crushed layer, m; hn - perebura, m. 1 Il.

Description

The invention relates to the mining industry, and specifically to the development of rocks by ledges, the upper part of which is destroyed by the effects of overdraft during blasting operations on the overlying step.

In the practice of an explosive case, methods are known for preparing rocks at a downstream development, including drilling wells with a drill, loading them with an explosive (B) in accordance with the conditions of bedding or characteristics of B, creating a stemming and blasting. However, irrational use of the energy of the explosion is allowed, and uniform crushing of the rocks is not achieved.

The closest technological solution is a method of explosive preparation of rocks at a lower development, including drilling wells with a drill, loading them with an explosive, creating a blockage and blasting. In this case, the amount of stemming is taken within the limits of 0.5-4 m, and the value of the upper destroyed layer is not established.

However, the known method has the following disadvantages. During the explosive preparation of rocks with well charges with re-drilling, the upper layer is smoked and exploded twice - first during the development of the overlying and then the underlying ledges. The placement of explosives in the upper disturbed layer of rocks of the ledge leads to an increase in the propelling effect of the explosion and to an undesirable developmental effect on the technology - a violation of the collapse compactness. When the explosive column is excessively lowered, a part of the rock mass remains, which does not expose the charge directly to the charge, which leads to an increase in the oversize output and drilling consumption.

The purpose of the invention is to improve the uniformity of crushing of rocks by ensuring that the exploded massif fully covers the crushing action of the charge. The economic effect of 0.005-0.007 p. per 1 m3 of blasted rock.

The goal is achieved by the fact that in the method of explosive preparation of rocks with the inferior development, consisting in

WITH

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ON 00

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wells with re-drilling, charging them with an explosive, creating a tamping and blasting, before charging wells on the exploding ledge, determine the depth of the damaged layer hc during the previous step, and the value of the tamping 3 is determined from

I3 2hc-hn

where 3 - the amount of stemming, m; hc - the value of the disturbed rock layer, m; hn - perebura size, m

The proposed method is illustrated in the drawing.

Part of the array is destroyed: from the side of the ledge under development - from the effect of charges 1 when working on the previous approach, from the upper platform of the ledge being developed (layer hc) - from the explosion of the charge breakthrough when developing the upper ledge. The remaining part of the array is subjected to the crushing effect of charges 2 of the projected explosion.

In the known method, the size of the layer hc is not established, which does not allow for monitoring the uniformity of the placement of explosives in the array. The magnitude of the disturbed layer hc can be determined, for example, if, when drilling one or two wells, the change in the drilling speed along the step height can be determined from the readings of the automated control system instruments.

For this, equipment of the Mode-SV type can be used. If in the indicated system the main regime parameters of drilling (force of feeding on the bit, frequency of its rotation, air flow) are kept constant, then the change in the drilling rate will reflect the change in rock properties along the step height and will allow to determine the layer size hc. In order to exclude the re-crushing of rocks within the hc layer, the stemming should be lowered in relation to the latter by the value (hc-hn), as can be seen from the drawing. Then the value of 13ab is determined from the expression 1eab 2g1s-G1n.

The method is carried out as follows.

In accordance with the passport for the production of drilling, in which the value of perebor (hn) is determined, the wells are drilled in the block. On the drill

machine tool, equipped with automated control equipment (ACS), one or two wells are drilled at constant parameters of the drilling mode, which allows

change the drilling rate along the step height and determine the value of the layer hc. The charges of this design are subject to blasting.

The implementation of the proposed method

shown for conditions of coal mines whose rocks are of sedimentary origin.

PRI me R. Under coal cutting conditions, sandstones are subject to blasting.

medium-grained (PS) with a high content of siliceous and carbonate material in cement, having a temporary compressive strength of up to 100 MPa and belonging to category IV by blockiness. Rock drilling is carried out by the SBSh-200-60 machine 3, which provides drilling of wells with a diameter of 0.216 m.

When drilling using the equipment Mode-SV, which is equipped with

the drilling machine, it has been established that for the conditions under consideration the layer size is hc 3.1 m, and the perebor depth is hn 1.9 m. Therefore, the amount of tamping will be

1zab, 1-1.9-4.3m.

Claims (1)

Invention Formula A method of explosive preparation of rocks with a retreating development, including drilling wells with a re-drilling, charging them with an explosive, creating a tamping and blasting, characterized in that to increase the uniformity of rock crushing, before charging wells on the exploding ledge, the depth of the broken rock layer hc was determined during the development of the previous ledge, and the damming 13 is determined from the expression I3, where In is the amount of welldown.