Brown Coal Bulletin, 2011 (vol. 51), issue 3

Coal reserve assessment in brown coal basins

Ing. Marcela Šafářová, Ph.D., Dr. Ing. Lubomír Chytka

Zpravodaj Hnědé uhlí 2011, 51(3)

The paper deals with brown coal and lignite reserves assessment from the view of predefined criteria which are used for coal reserve classification. The classification distinguishes four categories - geological, balance, out-of-balance, and workable reserves. These criteria, so called conditions, are based on qualitative parameters of coal, geological conditions of deposit, and mining and technological conditions. Reserve accounting, including their decrease due to extraction and other changes caused by a more detailed geological survey of the deposit, is provided in the form of a national balance in the Czech Republic.

Research of reclaimed sites in the territory of Severočeské doly a.s.

RNDr. Michal Řehoř, Ph.D., Vratislav Ondráček, doc. Mgr. Miroslav Šálek, Dr.

Zpravodaj Hnědé uhlí 2011, 51(3)

From 2004 to 2010, a large-scale research project funded by the Ministry of Education, Youth and Sports of the Czech Republic was handled by Výzkumný ústav pro hnědé uhlí a.s. The project was aimed at coal matter, from many points of view. The project also included land reclamation with regard to the importance and long-term perspective of this issue. In 2009, another research project specifically focused on reclamation started. This paper summarizes the main results achieved within both of the research projects.

Change of pressings strength due to air humidity and thermal shock

RNDr. Ing. Josef Valeš, Jaroslav Kusý, Ing. Lukáš Anděl

Zpravodaj Hnědé uhlí 2011, 51(3)

The paper describes the procedure which can detect moisture absorption in pressings. Changes of moisture values were determined in dependence on experiment edge conditions, i.e. relative humidity and temperature of the environment. Furthermore, the influence of water content in a pressing (moisture absorption, desiccation) on the change of its strength as well as a quick way of determining the strength of a pressing by a manual tester AK-14-E were tested in the experiment.

Research of possible approaches to predicting centres of spontaneous combustion of coal in brown coal heaps

Ing. Vlastimil Moni, Ing. Pavel Schmidt

Zpravodaj Hnědé uhlí 2011, 51(3)

Spontaneous combustion of coal and subsequent fires often occur in browncoal open pits where coal seam is uncovered by previous underground mining, or in coal heaps by homogenization plants, power plants, heating plants, and other factories where coal is combusted. The paper presents the objectives of the ALFA research project No. TA01020351, which focuses on the research, development and verification of a general method detecting early signs of incipient irreversible heating of coal matter which leads to spontaneous combustion of coal. The basic method uses a thermovision camera for a continuous monitoring of surface temperature in coal heaps or seams.

Electrical drives fault conditions measurement

Ing. Václav Škraban, Ing. Vlastimil Moni

Zpravodaj Hnědé uhlí 2011, 51(3)

Measuring electrical parameters of belt conveyor drives is one of complex measurements conducted in-situ. These measurements are aimed at finding key factors which determine reliability and service life of belt conveyors. The results will be used in order to design a new complex diagnostic system for belt conveyors.

Belt conveyor run-up measurements

Ing. Václav Škraban, Ing. Vlastimil Kraus

Zpravodaj Hnědé uhlí 2011, 51(3)

Failure rate of belt conveyors used in open pits is basically determined by run-up conditions, especially when the conveyor is fully loaded. The paper describes the run-up of two modernised belt conveyors, which are equipped with frequency converters providing a gradual run-up of the conveyor, and the run-up of two common belt conveyors without frequency converters. The description is based on the measurement of electric variables of these drive units.

Doubled tensioning system impacts on the belt conveyor PS 52

Ing. Petr Klouda, Dr. Ing. Lubomír Chytka, Ing. Vlastimil Moni

Zpravodaj Hnědé uhlí 2011, 51(3)

The paper, elaborated within the research project No. FR-TI1/537 funded by the Ministry of Industry and Trade of the Czech Republic, deals with possible factors which may cause a rip or a damage to the belt concerning belt conveyor systems where the drive unit is equipped with two take-up pulleys. Areview is presented in the paper, as well as calculations focused on take-up pulley diameter impacts on conveyor belt tension (rip detection).

Geophysical investigation of unexploded ordnance in the area of Želenice quarry

RNDr. Michal Řehoř, Ph.D., Ing. Tomáš Lang, prof. RNDr. Miloš Karous, DrSc.

Zpravodaj Hnědé uhlí 2011, 51(3)

In autumn 2010, two unexploded aircraft bombs were uncovered in the area of the phonolite quarry Želenice due to a stone debris slide. After their disposal by pyrotechnists, the place of their occurrence was confronted with results of a geophysical survey which was conducted in 2000. The surveyconfirmed that the location of the bombs corresponded with the most distinct anomaly revealed by the survey. The paper assesses methodology, achieved results, bombs location, and other perspectives of geophysical investigation.