Complex Measuring System for Longtime Monitoring and Visualization of Temperature and Toxic Gases Concentration

Deep coal mining has always been accompanied by an array of negative effects. One of the most significant is the occurrence of mining dumps in the vicinity of mining companies. Mining dumps (also dumps) are natural mounds where collateral rocks from the surroundings of coal seams that cannot be further industrially used were stored during mining. Concurrently, coal substance was also stored in dumps, either in its pure form or as an individual layer of the loose rock mass or as a part of the collateral rock (mostly clay stone) that contained variously thick layers of coal that could not be separated during the mining process. It is the most dangerous material of the mining dump that creates and spreads thermal processes, virtually in the entire volume of each and every dump. The amount of coal being stored together with collateral rock depends on the technology of separation and processing the product of a coal factory. Various analyses of the coal dump samples declare that percentage of combustible substances usually reaches 30%, while even 50% is not an exception. There are many old mining dumps in the MoravianSilesian Region. Several of them have been exposed to a very intense thermal process. The thermal processes, such as auto-oxidizing heating, endogenous as well as surface fires, occurred more or less constantly in mining dumps during last century. The occurring thermal processes represent a whole range of risks at a various degree of danger, some of which imminently threaten the lives of people. Last but not least, these processes also have a negative impact on the environment. The most serious risks arising from the existence of burning dumps include:  Development of heat. The burning of the combustible parts of a dump releases considerable heat. The heat then uselessly leaks into the atmosphere and contributes to the disturbance in the natural balance of the given location;  Releasing toxic substances. Each mining dump contains a non-homogenous mix of carbon rock, coal as well as household and industrial waste that also used to be uncontrollably dumped at mining dumps during the operation of a coal factory. During fires, not only coal substances, but also all organic substances in the dump and illegally dumped chemicals in the last resort burn. The production of extremely toxic CO that is created as the product of imperfect combustion with the lack of oxygen is the most severe and extensive danger as the CO concentrations may become lethal, particularly in the immediate vicinity of gas outlets in burning dumps. CH4 methane is another highly toxic gas [4];  Generation and spread of fine dust;  Creation of burnt-out space within the dumps;  Risk of a surface fire;  Negative impact on ecosystems.


Introduction
Deep coal mining has always been accompanied by an array of negative effects.One of the most significant is the occurrence of mining dumps in the vicinity of mining companies.Mining dumps (also dumps) are natural mounds where collateral rocks from the surroundings of coal seams that cannot be further industrially used were stored during mining.Concurrently, coal substance was also stored in dumps, either in its pure form or as an individual layer of the loose rock mass or as a part of the collateral rock (mostly clay stone) that contained variously thick layers of coal that could not be separated during the mining process.It is the most dangerous material of the mining dump that creates and spreads thermal processes, virtually in the entire volume of each and every dump.
The amount of coal being stored together with collateral rock depends on the technology of separation and processing the product of a coal factory.Various analyses of the coal dump samples declare that percentage of combustible substances usually reaches 30%, while even 50% is not an exception.
There are many old mining dumps in the Moravian-Silesian Region.Several of them have been exposed to a very intense thermal process.The thermal processes, such as auto-oxidizing heating, endogenous as well as surface fires, occurred more or less constantly in mining dumps during last century.The occurring thermal processes represent a whole range of risks at a various degree of danger, some of which imminently threaten the lives of people.Last but not least, these processes also have a negative impact on the environment.The most serious risks arising from the existence of burning dumps include:  Development of heat.The burning of the combustible parts of a dump releases considerable heat.The heat then uselessly leaks into the atmosphere and contributes to the disturbance in the natural balance of the given location;  Releasing toxic substances.Each mining dump contains a non-homogenous mix of carbon rock, coal as well as household and industrial waste that also used to be uncontrollably dumped at mining dumps during the operation of a coal factory.During fires, not only coal substances, but also all organic substances in the dump and illegally dumped chemicals in the last resort burn.The production of extremely toxic CO that is created as the product of imperfect combustion with the lack of oxygen is the most severe and extensive danger as the CO concentrations may become lethal, particularly in the immediate vicinity of gas outlets in burning dumps.CH 4 methane is another highly toxic gas [4];  Generation and spread of fine dust;  Creation of burnt-out space within the dumps;  Risk of a surface fire;  Negative impact on ecosystems.

Monitoring temperatures and gas concentrations in mining dumps
The aforementioned facts imply that it is absolutely essential to carry out long-term measurements of temperatures as well as concentrations of hazardous gases (CO, CH 4 ) in thermally impacted mining dumps.The monitoring of the quantities may be divided into two basic groups.The first one includes regular manual measurements of temperatures and gas concentrations in special probes with the use of manual portable measuring instruments.
The second option, considerably quantitatively and qualitatively better, is to use special measuring systems that will ensure regular measurements of temperatures and gas concentrations as well as other quantities in defined time intervals and their subsequent transmission to a dispatching station.The first measurement method has a whole array of disadvantages, the major one being the necessity to manually measure and   ameter (lower m).The value o m of methane) sor requires a perature.

CO and CH 4 asuring system
As Fig. 4 sh em is a teleme well as current measuring gas system w lications at medical Eng ctrical signals

CO, CH 4 me
The telemet uired quantitie es the measur rvals (most fr data to the se cessed, visua ned times by ualization of th website.Data are archived at the dispatching station in a MySQL database, which together with PHP represents the basis of an own information system about the monitoring based on a dynamic website.The website contains basic information about the monitored locality, including photographs and diagrams of the locations of the individual measuring probes.Furthermore, there is an option to display dynamic graphs and historic trends of selected quantities in the particular probe, including the display of the current values.

Response to alarm status
The website mentioned above displays the current values, historic trends, graphs for particular quantities at a selected time and so on.If the limit value of any quantity is reached (according to the selected levels as mentioned above), authorized persons must be immediately notified.The method of notification is divided into the following categories:  Visual information on the website, by a change in the color of the information window for the measured quantity to red with a flashing effect and an acoustic alarm signal. Sending a warning information email to specified persons, including exact designation of the measuring location and information about the measured value of the particular quantity. Sending a warning SMS to specified persons, including exact designation of the measuring location and information about the measured value of the particular quantity.

Conclusions
The contribution provides a description of a unique measuring system that monitors the temperature and hazardous gas concentrations within old mining dumps affected by thermal processes in the long term.The development of the system started several years ago and the individual prototypes have been tested and installed in the Hedvika and Ema mining dumps.The greatest problem that has to be considered in the design and construction of the measuring system is the extreme natural conditions at the place of its installation, which namely include high temperature (approximately 150°C).With regard to the complicated calibration of the gas sensor for temperatures exceeding 60°C, the system will be soon adjusted for the use of a different type of sensor (electrochemical sensor [7]).With regard to the necessity of feeding the entire system by batteries (unavailability of 230V), the following development will focus on the minimization of consumption of all components (replacement of sensors with a combined CO + CH 4 gas sensor). r Fig.Mea