This paper describes the concept of controlling the advancement speed of the shearer, the objective
of which is to eliminate switching the devices off to the devices in the longwall and in the adjacent
galleries. This is connected with the threshold limit value of 2% for the methane concentration in the
air stream flowing out from the longwall heading, or 1% methane in the air flowing to the longwall.
Equations were formulated which represent the emission of methane from the mined body of coal in the
longwall and from the winnings on the conveyors in order to develop the numerical procedures enabling
a computer simulation of the mining process with a longwall shearer and haulage of the winnings. The
distribution model of air, methane and firedamp, and the model of the goaf and a methanometry method
which already exist in the Ventgraph-Plus programme, and the model of the methane emission from the
mined longwall body of coal, together with the model of the methane emission from the winnings on
conveyors and the model of the logic circuit to calculate the required advancement speed of the shearer
together all form a set that enables simulations of the control used for a longwall shearer in the mining
process. This simulation provides a means for making a comparison of the output of the mining in the
case of work using a control system for the speed advancement of the shearer and the mining performance
without this circuit in a situation when switching the devices off occurs as a consequence of exceeding
the 2% threshold limit value of the methane concentration. The algorithm to control a shearer developed
for a computer simulation considers a simpler case, where the logic circuit only employs the methane
concentration signal from a methane detector situated in the longwall gallery close to the longwall outlet.
Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA) nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS) data.
Since the 1970s, the Legnica-Głogów Copper District has an area of intensive mining of copper. Mining activities resulted in the appearance of induced seismic activity. This situation caused the necessity of setting an underground seismological network. In the mid-1990s, due to the great damage of objects on the surface caused by the ground vibrations due to mining tremors, a surface strong motion seismic network equipped with accelerometers was created. They monitor the vibration levels of both the land and the buildings themselves. This contributed to a better knowledge of the nature of ground vibration and the resistance of objects. In recent years, anthropogenic threats, which include seismicity induced by mining activities, are arousing more and more interest. To be able to develop test methods for seismic source physics, the analysis of the impact of vibrations on the surface and the seismic hazard, network measurement should also be developed and modernized. In the years 2014–2015, the IS-EPOS “Digital research space of induced seismicity for EPOS purposes” project, extended the LUMINEOS modern seismological network presently consisting of 15 seismometers and 10 accelerometers, with the possibility of additional further expansion. The data obtained from the LUMINEOS network complements the existing underground mining network and surface strong motion network. This allows for an advanced seismic analysis.
The paper presents a method of structural monitoring with the use of angular displacement measurements performed with inclinometer devices. Inclinometer method is a solution free from the basic disadvantages of optical methods used commonly in structural monitoring, such as sensitivity to any type of visibility restrictions, pollution or influence of weather conditions. At the same time, with appropriate sensor parameters, a much better measurement accuracy is obtained than for typical optical methods and very low energy demand and moderate costs are achieved. Taking into account the above-mentioned issues, in the first stage an appropriate MEMS-type inclinometer sensor was selected, its laboratory tests were carried out and a method of the offset temperature drift correction, individual for each sensor, was developed.
The paper presents a method of structural monitoring with the use of angular and linear displacement measurements performed using inclinometer and laser measuring devices. The focus is mainly on the inclinometer measurement method, which is a solution free from the basic disadvantages of optical methods, such as sensitivity to any type of visibility restrictions, pollution or influence of weather conditions. Testing of this method was carried out in practical application in an wireless monitoring system, installed in a large-area industrial building. The measurement results performed using the inclinometers were compared with simultaneous measurements of linear displacements performed with the use of proven methods based on laser rangefinders. The research and analysis show that the method of measuring angular displacements using the inclinometers with MEMS sensors of appropriate quality is a very good, better than typical optical methods, solution of structural monitoring systems that allows to obtain accurate and reliable results.
In 1989/90, in the region of SSSI 8 situated on King George Island 21 bird species were observed, 12 species were breeding. Dominants were 3 Pygoscelis species (19229 pairs). Five species of pinnipedians were noticed. Mirounga leonina was most abundant in January (623 individuals), Arctocephalus gazella — in February and March (890 individuals), Hydrurga leptonyx in October (39 individuals). The abundance of Leptonychotes weddelli was low and rather stable. As a result of mild winter during the study period such birds as Sterna vittata and Pygoscelis adeliae stayed near their breeding places. The scarcity of Lobodon carcinophagus was probably also a result of this mild winter.
In the breeding season 1988/89, within the region of SSSI No. 8, nesting of 12 species of birds was observed. The highest number of nests — 24430 — belonged to three species of pygoscelid penguins; 77.1% were the Adelie penguin. Relatively high fluctuations in the number of penguins in some rookeries in particular breeding seasons were confirmed. During regular countings of mammals' in 1988 the presence of 5 species of Pinnipedia was noted, of which the southern elephant seal was most numerous in the summer season, whereas crabeater seal — in winter. In the region of SSSI No. 8, breeding of southern elephant seal and Weddell seal was observed. Fluctuations in the number of seals in this region in the period 1977—1988 were insignificant.
The assessment of a rock’s behaviour around excavations and the effectiveness of its reinforcement in underground ore mines is dependent on the performance of the rock-bolt and rock-mass interaction, which can be estimated on the basis of appropriately designed measurements. Based on the background of various measurements solutions described in the literature, concerning rock bolt monitoring methods, the authors proposed a new, original device for mass measurements in mine conditions. After examining the advantages and disadvantages of existing constructions, the article presents the essence, principle of operation and method of measuring anchor load in an underground excavation with the a instrument, indicator WK-2/8. The prototype has been carefully researched and successfully tested in a full-scale laboratory environment. This instrument, also referred to as a load indicator or force pad, does not require electrical power and allows for relatively accurate (with a resolution of 10-14kN, up to about 90kN loading capacity) and a remote reading of the axle loading of the anchor (AGH patent) by any person present in the specified area. The device can be installed in mining excavations under loading conditions. The relatively low cost of a measuring instrument, practically used as an additional washer, as well as an easy assembly method, makes it universally applicable in mines where anchoring is used as a means of strengthening the rock.
The paper presents the results of seven-year survey of Antarctic seals along the western shore of Admiralty Bay, King George Island, South Shetland Islands. Five species were monitored during seven of the eight years, between 1988-95, excluding 1993. Numbers of elephant seals and Antarctic fur seals showed strong annual cycles, fur seals with two seasonal peaks. These of the other three species were more irregular. Fewer Weddell seals were seen in 1994 and 1995 then during the period 1988-92; with this exception, no overall trend in numbers was apparent during the period 1988-95.
The utilization of mining waste is an important problem in Poland and Ukraine. The article presents one of the variants of waste mining in the quarry in Płaza. An analysis of the resource base of the deposit and their location at the area of Płaza deposit is carried out. The Płaza deposit is located in the western part of the Małopolskie province, in the entire Chrzanów commune. The Płaza deposit is constructed of Middle Triassic carbonates represented by the limestone-dolomite Olkusz Formation and the limestone-marlized Gogolin Formation. The deposit series lies on the dolomites of Röt age (Lower Triassic – Olenekian). The most valuable raw material was the pure limestone from the lower part of the Olkusz Formation, now almost completely exploited. The article presents the current state of mineable reserves of the deposit and their quality (chemical and physical characteristics). Moreover the article shows potential consumers of raw material and the possibility of extending the life of the mine work. According to the results of the environmental monitoring the ground and hydrogeological conditions were evaluated, the results of which allowed a more efficient use of the existing quarry area for mining waste disposal to be proposed. The paper presents a conceptual waste transport scheme, planned distribution and compaction of wastes belonging to the first, second and third group and then a surface reclamation. In view of the absence of similar decisions analogs, the consideration of the open-pit as a one solid geomechanical system functioning under the conditions of uncertainty is suggested. In order to examine the dynamics of the waste compaction process, some measures are foreseen to constantly observe their subsidence. The proposed measures for the synchronous disposal of mining waste in the worked-out area of the open-pit and the simultaneous mining operation in the quarry will allow the life cycle of the open-pit to be prolonged for 15–20 years.
A mine cannot function without monitoring systems: environmental, basic mining machinery and equipment. The exploitation of ore in the mine depends heavily on properly functioning machines and mining equipment, and acceptable for the miner technical environmental conditions occurring in underground excavations. The monitoring systems of the technical environment in underground mines are primarily telemetry and gasometry systems. The first part of the article shows the typical structure of gasometry systems operating in the Polish underground mines. The existing provisions include the so-called security systems of the mining plant. The article presents a quantitative summary of the telephone exchange types and count of main telecommunication lines operating in these systems. Monitoring systems of machines and mining equipment are an essential element of the effec-tive management of the mine, because they affect the safe operation and increase time of effi-ciency equipment. The second part of the article shows selected monitoring systems of mining machinery and equipment currently used in the dispatcher rooms of mines. Attention was paid to the monitoring systems, which are only software tools as well as those in which additionally use dedicated IT solutions for these systems, hardware and measuring tools. The table shows the types of monitoring systems and technological configurations used in underground mines, preferred for them.
SQL Injection is one of the vulnerabilities in OWASP's Top Ten List forWeb Based Application Exploitation. These type of attacks take place on Dynamic Web applications as they interact with databases for various operations. Current Content Management System like Drupal, Joomla or Wordpress have all information stored in their databases. A single intrusion into these type of websites can lead to overall control of websites by an attacker. Researchers are aware of basic SQL Injection attacks, but there are numerous SQL Injection attacks which are yet to be prevented and detected. Over here, we present the extensive review for the Advanced SQL Injection attack such as Fast Flux SQL Injection, Compounded SQL Injection and Deep Blind SQL Injection. We also analyze the detection and prevention using the classical methods as well as modern approaches. We will be discussing the Comparative Evaluation for prevention of SQL Injection.