Shtashkevych Tatyana

"Influence of maintenance of inert additions on preventive properties of explosives"

INTRODUCTION

On territory of Donbassa plenty of coal - about 80 million tons is obtained on a year. But mining is a very dangerous process.

Combustible gases, and also coal dust, are selected in the atmosphere of many underground making. These factors are dangerous and can form an underground explosion or fire, which will result in large destructions. About 40 explosions of gas and dust, about 80 flashes of methane, about 700 fires, 1400 bringing down and obstructions of mountain mines, happened for the last twenty years. About 3400 persons perished, from them about 35% at failures with group cases[1].

One of principal reasons of formation of explosion of gas and dust is influence of sources of heat on an explosive environment at mining.

By explosives in our time an about 10% coal is obtained and about 40% preparatory works are conducted. On the enterprises of coal industry about 8 thousand of tons of explosives is expended every year, from them about 5 thousand of tons – preventive [2].

In order to avoid an explosion, it is necessary to observe the rules of safety. One of major safety measures are applications of preventive explosive matters.

A research object is an ammonite of P5 and ammonite of G5, made at the Donetsk public plant of chemical wares.

A purpose of work is research of influencing of maintenance of inert admixtures on preventive properties, determination of optimum terms for conducting of injury of preventive explosive matters.

Actuality of work consists in that ammonites which use for conducting of injury in mines dangerous on gas contain inert admixtures and prevent inflammation which can cause the explosion of methaneair mixture, and will render assistance to the collapse of mine.

1 FEATURE of SELECTION OF METHANE AT IMPLEMENTATION of BLASTING WORKS

During the process of destruction of gas-bearing mountain range an explosion it is possible to select the row of features.

At the rapid explosion of complete set of opening charges for the short interval of time there is tearing away, crushing and moving of considerable volumes of coal mass, selection of methane. By reason of rapid selection of methane from the crushed coal is a speed process of destruction. This process is closed very quickly in the first seconds after an explosion. Till now part of methane which was selected has time to pass to the atmosphere of near making space. Intensity of selection of methane depends on gassing of coal, volume and degree of crushing of the reflected mountain mass.

It is also necessary to say that maintenance of methane in making depends on the amount of air which is given in it in the first seconds after injury, rather than just from gassing.

Research of dynamics of methane at the blasting robots of explosive matters of the IV class is shown:

a) growth of selection of methane is observed already through 25 ms after the serve of current in an explosive network;

b) The explosive concentrations of methane in near making space of making at blasting robots do not appear for period of time to 250 ms inclusive. Such amount of methane even at the two-bit of explosive coal dust can result in an explosive environment in making;

c) Through 0,6...5 with after the beginning of explosion concentration of methane in near making spacious can arrive at an explosive limit.

At presence of ventilation of making the explosive concentrations of methane in near making space can contain within the limits of a few minutes, and on occasion to 10 min. after the production of blasting works[3].

2 PREVENTIVE EXPLOSIVE MATTERS of G5, P5

Ammonites of G5, P5 are powdery preventive proof to moisture explosive of the IV class, admitted to application in mining industry, in coal mines, dangerous on gas and dust.

Intended for an explosion on coal and breeds of any durability at any floods of openings in terms. Cartridges are subject loading by hand. Ammonites of G5, P5 can be saved and used in all climatic districts. Ammonites of G5, P5 produce in cartridges a diameter 36-37 mm, by mass of a 300 grame at the closeness of explosive in the cartridge (1,05-1,20) of g/cc.

Production of cartridges in shells from the paper of yellow. On every cartridge it is necessary to inflict a paint marking[4].

3 METHOD OF TEST IN METHANEAIR MIXTURE

Cartridges consistently in sequence close place mortars in a channel. In it at moving admit gas in an amount, necessary for creation of his concentration in mixture with air (9,0±0,5)% on volume. From an explosive typewriter give an impulse on electro- detonator of the tested charge and after an explosion last register by sight took place or did not take place inflammation of methaneair mixture[5].

Explosives consider surviving a test at frequency of inflammation of methaneair mixture in 20 experiments in succession – not more than 50%. At the receipt of negative results conduct the repeated tests with the doubled amount of experiments.

Results of the repeated tests are final.

BASIC RESULTS

The questions of influencing of amount of inert connection were considered in the resulted work, oxygen balance and power properties on the amount of flashes at injury of ammonites which are one of major descriptions of preventive explosive matters.

The most of flashes is observed at the least content of inert connections in explosives of matter, thus, maintenance of inert connection influences on preventive properties of explosive matters, at content of inert connection anymore 0,205kg (for the ammonite of G5) and more than 0,208 kg (for the ammonite of P5) of flash were not observed.

At oxygen balance to near there is the least amount of flashes to zero, and at the rejection of him in a positive (ammonite of P5) or negative (ammonite of G5) side, the amount of flashes is increased and the products of incomplete oxidization appear – NO, N₂, CO, and also combustible gases – Н₂, СН₄. They are negative and negatively influence on an atmospheric environment. It is possible to draw conclusion from it, which the presence of inert connection and oxygen balance is rendered by direct influence on the amount of flashes [6].

At consideration of influencing of power properties on the amount of flashes of methaneair mixture, there was growth of amount of flashes at growth of power indexes (warmth of explosion, content of gases which appeared during an explosion and temperature of inflammation). In the ammonite of G5 there were 11 flashes at the highest power indexes - party was defective [7].

During storage in cold storages, under covers, at transporting, admixtures can to make oneself dirty, and their humidity to rise.