Problem and principal directions of problem-solving

The basic direction of development coal industry is an adventures creation “lava-mine”, which secures coal production to 20000 t/day. The rise of coal production allows deflating on coal; reduces the quantity of mines and raises the safety of mining. The key condition to realize a high resource by the new mining machinery is the timely preparation of breakage face, i.e. for the space of working lava must be prepared and equipped by equipment new lava.

When moving the spade-excavation can be found the insertions of higher strength in rocks massif. The modern machinery, which allows the destruction pillars with σpr<110 MPa, can not secure the excavation this insertions. To use alternatively the drill+blast is not expedient in consequence of low productivity and high risk of the work.

Therefore the further rise the technical level of heading machine is the issue of the day in development of mining engineering.

Animation 1. The scheme of destruction the rocks by heading machine
(amount of pictures - 20; amount of repetition cycles - 50; dimension - 18,1 KB )

In the literature is often underscoring the necessity of the enlargement of tunneler application sphere on hard rocks. But simple and expedient variant for decision this problem is not. On the basis of analysis theoretical investigations and experimental facts designed four directions of problem-solving:

1) The enhancement of cutting tools head;

2) The applications milling cutters as working instrument;

3) The overlap cutting with percussion loading;

4) The use the hydro mechanical method of destruction.

On the other hand the rise of coal production can be reached by means of:

1) Turbo advance speed of machine at the expense of increase the power drive and optimization the conditions of destruction;

2) Increase the work time the readiness by excavation on the basis of enhancement organization works and shortening the time on realization of theirs, and increase the coefficient readiness and shortening the time on maneuver operations and substitution tools too.

The substantiation the progressive direction of rise the technical level of heading machine is the object in my master’s work.

The choice a progressive direction of rise the technical level of heading machine

Today as primary working instrument for destruction the rock is using the tools. But the considerable imperfection in cutting is the restriction in using on rock with small strength.

The one part of power at cutting is spending on breaking rock and another part is spending on overcoming the friction of tool by rock. At the friction of tool by rock can much calorification and material of tool is smelt.

So apparently that tool is an instrument of short duration as a result of quick deterioration especially on hard rocks and it requires often substitution. Besides at rise the process excavation the quantity of tools, which stopped working, rises steeply.

At the moment there are not investigations by appraisal influence costs time on the substitution tools on adequate technical productivity in high productive complexes. Aaccount must be taken that so as to establish facts the influence on difference between technical and operational productivity in mining machines.

As the criterion for appraisal influence costs time on the substitution tools on adequate technical productivity passed the coefficient exceeding technical productivity in complex over operational:

Êïð=Qòåõ/Qý,

where

Qòåõ – specified operational productivity in complex, t/day;

Qý – adequate technical productivity in complex, t/day.

For appraisal influence costs time on the substitution tools were calculated dependences Êïð for different values the expenses of tools and the coefficient readiness from adequate value operational productivity, which showed in the picture 1. For calculations the value costs time on the substitution one tool take equal 0,5 minute.

Picture 1. Dependences of coefficient exceeding Êïð from adequate value operational productivity for different values the expenses of tools and Kã=1.

Besides for appraisal influence coefficient readiness system Kã from Êïð makes dependences, which showed in the picture 2.

Picture 2. Dependences of coefficient exceeding Êïð from adequate value operational productivity for different values the expenses of tools and coefficient readiness system Kã.

On the basis of analysis the findings apparently that at the operational productivity to 20000 t/day the coefficient exceeding is founding in limit 1<Ê<2,5. Most that showed in the hard conditions of mining (on hard rocks).

This resume evidences that at the rise of mining works is expedient replace tools by most safe and perennial instrument.

In Russia and abroad there is staging of scientific investigations which shows that the rise productivity in heading machines without increase overall dimensions and mass of they and application of them on hard rocks can be reached on the basis of hydro mechanical method of destruction.

Alternatively milling cutters can be used as working instrument in heading machines. Usage the milling cutters instead of tools must diminish great quantity expenditure of instrument and influence costs time on the substitution of them too.

Resume and direction of further investigations

In master’s work have been made expedient substitute tools on milling cutters in head of heading machines.

The further investigations will be done in direction on making the high-powered head of mining machine on the basis of milling cutters.