Approved by the Order of Committee on the state control of emergency situations and industrial safety of the Ministry on emergency situations of the Republic of Kazakhstan of August 20, 2008 No. 33

Methodical instructions for preventive silting and suppression of the underground endogenous fires on chalcopyrite mines of the Republic of Kazakhstan

Introduction

Methodical instructions intend for management when conducting underground mining operations on the operated fire-dangerous ore fields, and also when designing mines on again reconnoitered ore fields provided by sulphidic ores and the containing breeds inclined to spontaneous ignition.

Chapter 1. General provisions

1. The miner fires in case of development of ore fields for the reasons of their origin are divided on:

1) endogenous, arising from spontaneous ignition of sulphidic ores and the containing breeds as a result of their oxidation;

2) exogenous, arising from ignition of combustible materials under the influence of any external sources of heat.

2. The endogenous fires on mines arise in the fulfilled space in case of systems with collapse, in cameras with zamagazinirovanny ore and also in the destroyed tselika and potolochina.

3. The oxidized components in sulphidic ores and the containing breeds are sulphidic minerals: pyrites, marcasite, melnikovitpirit, pyrrhotine, chalcopyrite, kovellin, blende and others.

4. Oxidation of sulphidic ores and breeds comes continuously due to absorption of oxygen from the miner atmosphere and is followed by allocation of certain amount of heat. Processes of oxidation of ore and breed in case of their humidity are especially intensive of 1 - 4%.

5. The oxidizing processes reaching stage of the endogenous fires develop in the course of conducting clearing works and do not depend on whether they are conducted by systems with bookmark or with preventive silting, that is can arise in case of any system of the development allowing temporary magazinirovaniye of ore in clearing face.

6. In case of bad heat exchange with the environment heat accumulates in the developed space and conditions for formation of the centers of self-heating are created. In case of warming up of ore and breed their chemical activity in relation to oxygen increases in 1,5 - time 2,0 on everyone 10 about From temperature increase.

7. Miner conditions in case of not intensive issue of the beaten-off mountain weight from clearing cameras and preparatory developments favor to development of oxidizing processes. Heat which is formed due to oxidation of walls of developments and the beaten-off mountain weight increases temperature of miner air and worsens working conditions in clearing cameras and driving faces of deep mines. Specific heat releases from surface of loose excavations can reach 25 - 52 kcal/m 2.chas.

8. The current state of study of origins of the underground endogenous fires in case of development of copper and pyritic fields allows to consider that wood availability in the fulfilled space promotes more bystry emergence and more intensive course of the endogenous fires as spontaneous ignition of sulphidic ore is possible at temperature of 350 - 500 With, and temperature of ignition of the hydrolyzed wood - 180 - 200 Pages.

9. The most probable places of emergence of the underground endogenous fires:

1) in case of systems with collapse - areas extinguished rising, ore chutes and the brought-down space;

2) in case of systems with dry stowing - areas extinguished unmortgaged rising, ore chutes and sites, with the unmortgaged emptiness having the message with the operating excavations or with surface;

3) in case of systems with ore magazinirovaniye - in the beaten-off ore.

10. Signs of development of oxidizing processes are:

1) the change of composition of miner air in clearing faces which is characterized by decrease in content of oxygen and increase in carbonic acid;

2) increase in faces of air temperature, the beaten-off ore and water;

3) gradual increase in miner water of free sulfuric acid (over 0,2 - 0,3 of g/l).

Sign of the underground endogenous fire in case of development of ore fields - steady content in the tests of miner air which are selected in clearing faces in case of the stopped fans of local airing every 3 - 4 hour, carbon monoxide 0, by % and above or sulphurous 0,001 gas of % and above throughout two days if presence of these gases is not connected with explosive works. In case of the underground fire there can be in places, available to observation, in excavations both both specified gas, and one of them.

Chapter 2. Classification of ores and fields by fire danger degree

11. Four types of ore fields are allocated:

1) the first type - fields in which ores are inclined to spontaneous ignition and the containing breeds do not ignite spontaneously. Typical representatives of this type are pyritic and copper-nickel fields;

2) the second type - fields are put by ores and the containing breeds inclined to spontaneous ignition;

3) the third type - fields are provided by not igniting spontaneously ores, and the containing breeds are inclined to spontaneous ignition;

4) the fourth type - the fields provided by not igniting spontaneously ores and the containing breeds.

12. Tendency of sulphidic ores and the containing breeds to oxidation is different and depends on material (mineralogical) structure and textural and structural features. On degree of tendency to spontaneous ignition sulphidic ores and the containing breeds are subdivided into 3 classes:

The 1st class - inclined to spontaneous ignition;

The 2nd class - low-inclined to spontaneous ignition;

3rd class - not inclined to spontaneous ignition.

In case of their operation exert impact on fire danger of fields it is mountain - geological conditions.

13. Depending on class of sulphidic ores and the containing breeds and mountain geologicheekim to bedding conditions (capacity and hade of ore body) ore fields are classified by degree of tendency to spontaneous ignition on 3 types:

The 1st type - fire-dangerous fields;

The 2nd type - a little fire-dangerous;

3rd type - not fire-dangerous fields.

Classification of fields is given in table 1.

Chapter 3. Choice of systems of development of fire-dangerous ore fields

14. The ore fields provided by ores 1 - go klassasklonny to spontaneous ignition, in case of underground method are developed by systems with continuous filling of the developed space with the hardening bookmark. At the same time, the time spent of the beaten-off ore in face (camera) constitutes no more than 5 - 7 days.

15. In case of development of ores I of class systems with ore collapse (floor, subfloor and layered collapse) are not applied, including with preventive silting and systems with magazinirovaniye are not applied as the working off of the field which are not providing fire safety.

16. By underground mining of ores II of class depending on mining conditions application is allowed:

1) systems with the hardening bookmark;

2) systems of floor, subfloor and layered collapse with preventive silting;

3) systems with ore magazinirovaniye with the subsequent bookmark (in case of application of dry stowing are carried out subsequent its proilivaniye by clay solution);

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