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The document is cancelled since  December 4, 2015 according to Item 1 of the Order of the Minister of Internal Affairs of the Republic of Kazakhstan of December 4, 2015 No. 993

Approved by the order of the Minister of Emergency Situations of the Republic of Kazakhstan of July 25, 2008 No. 132

The temporary instruction on security measures and the prevention of explosions of sulphidic dust on the underground mines developing piritsoderzhashchy ores

Chapter 1. General information about explosions of sulphidic dust

1. The sulphidic dust which is formed in case of explosive destruction of strong, piritsoderzhashchy ores can form explosive concentration (aero suspensions) in air and ignite in case of impact on it thermal source with temperature at least 800 Pages.

2. Burning of sulphidic dust depending on intensity of the initiating impulse can proceed in the different modes:

stationary burning with speed of distribution of flame from several m/s to the first tens of m/s;

the explosive non-stationary burning (deflagration) extending with speed of smaller speed of sound in air;

detonation, with speed in several km/s.

In miner conditions the most characteristic forms of burning of dust are stationary and explosive (deflagration).

3. Exothermic reaction of oxidation of pyrites which main products are sulphurous gas (SO2) and oxides of iron (Fe2O3 and Fe3O 4) is the cornerstone of explosion (flash) of sulphidic dust.

4. Source of initiation of explosions (flashes) of sulphidic dust are explosive works.

Explosion (flash) of sulphidic dust in the mine is followed:

formation of considerable amounts of sulphurous gas which concentration in excavations can reach 1% and more;

distribution of flame on excavations on distance to 25 m (in case of shpurovy otboyka and secondary crushing of ore superimposed charges) and to 100 m (in case of detonation of borehole charges);

short-term temperature increase of air in zone of explosion of dust to 1000 - 1200 With;

shock air wave.

5. Poisonings of people with sulphurous gas can be negative effects of explosions of sulphidic dust, idle times of mining operations owing to gas contamination of excavations, damages fix, the mine equipment, the underground fires.

6. The major factor characterizing explosibility of sulphidic ores is content in it pyritic sulfur. The lower explosive limit of content of pyritic sulfur constitutes 35%.

7. The greatest danger is constituted by explosive destruction of strong, monolithic piritsoderzhashchy ores as in case of otboyka of such ores "lumbago" of charges of wells (shots) is possible.

8. Potential of explosion of the weighed sulphidic dust depends on its chemical and mineralogical structure, concentration in air, fineness of particles, humidity.

Dust of thermally unstable sulfides of iron of subgroup of pyrites (pyrites, marcasite, melnikovit-pyrites) is most explosive. Dust of pyrrhotine, chalcopyrite, blende is less explosive. Dust of bornite, chalcosine, galenite are not explosive.

9. The lower explosive concentration limit of content of dust in aero suspension constitutes 80 g/m3 - the minimum quantity of the weighed dust in air unit of volume, necessary for initiation of explosion in case of sufficient intensity of the initiating source.

10. Dust particles the size from 0,3 of mm and take part in explosion below, the greatest potential of explosion particles have the size less 0,1 of mm.

11. Source of ignition of sulphidic dust on mines are high-temperature products of detonation explosive substances (further - VV).

12. Explosions of dust happen in case of detonation of borehole, shpurovy and superimposed charges.

13. The strongest explosions of pyritic dust are possible in clearing cameras, especially at the last stage of their working off, with large volumes of emptiness when concentration of dust in gas-and-dust cloud exceeds the lower concentration limit, and the free amount of clearing space contains enough oxygen for course of reaction of oxidation of mass of the weighed dust.

14. Takes part in explosion as the dust which is formed in case of explosive crushing of array and the dust which accumulated earlier on walls and the soil of excavations.

The dust which accumulated earlier turns into suspension under the influence of the shock air waves arising in case of explosion of charges of VV.

15. In case of humidity more than 5% the accumulated dust loses capability to turn into suspension.

16. Danger of emergence of explosions of sulphidic dust in case of borehole otboyka depends also on mining technological factors: lines of the smallest resistance (further - lns), method of detonation and amount of free clearing space in the camera, like the applied VV.

17. For elimination of lumbago size l.n.s (dropped out) wells and effective otboyka of strong piritsoderzhashchy ores. shall not exceed 30D (D - diameter of well).

18. Intensity of explosion of sulphidic dust depends on ratio of mass of the blown-up charge and amount of free clearing space. It is determined that explosion or flash of dust does not happen if the amount of the gaseous products formed in case of explosive decomposition of VV makes at least 2 amounts of settlement zone of distribution of explosion of sulphidic dust.

19. Big danger to explosion of pyritic dust is constituted by deflagration cases (unstable explosive burning) ammoniac selitrennykh the elementary VV, causing increase in time of interaction of products of its decomposition at sulphidic dust.

For the prevention of cases of deflagration of VV and secondary explosion of pyritic dust in case of detonation of ore faces of I and II groups by shpurovy method application of igdanit with use of solid ammonium nitrate with smooth granules or granulite of D5 is limited.

20. Potential of explosion of sulphidic ores on the underground mines developing piritsoderzhashchy ores shall be determined ekspertno.

Chapter 2. Separation of faces (developments) on degree of potential of explosion

21. Degree of potential of explosion of sulphidic ores is established not on mines in general, and on separate developments.

22. The developments dangerous on explosions of sulphidic dust, are divided into two groups:

developments which take place on the ore containing more than 35% of pyritic sulfur which coefficient of fortress does not exceed 16 on scale of the prof. M. M. Protodjyakonov concern to the 1st group;

developments which take place on the ore containing more than 35% of pyritic sulfur and which coefficient of fortress exceeds 16 concern to the 2nd group.

23. The list of explosive developments (with indication of group) affirms monthly chief engineer of the mine (mine).

24. Treat the second group as well those developments in which the dust explosion case will be registered.

25. Assessment of danger of the faces (developments) operating and planned to working off and reference to category of potential of explosion is performed on the basis of geological approbation of geological service of the mine.

26. The list of dangerous developments (with indication of group of danger) is constituted by monthly geological service of the mine and affirms the chief engineer of the mine.

Chapter 3. Measures of safe conducting explosive works on sites of piritsoderzhashchy ores

1. The organization of observations and the advancing control

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