Yer altı maden işletmelerinde havalandırma ve bilgisayar destekli optimizasyonu

Abstract

Yeraltı maden işletmelerinde havalandırma; hem çalışanların sağlıklı çalışma koşullarında olmaları hem de ihtiyaç duyulan makinelerin güvenli ve uzun ömürlü çalışmaları için yapılan en önemli operasyondur. Çalışanlar için solunabilir hava tedariki, ortamdaki patlama riskinin ve toz konsantrasyonunun kontrol altında tutulması, kullanılan çalışma yöntemine göre çalışanların fiziki faaliyetleri de dikkate alınarak çalışma şartlarına uygun hava özelliklerinin sağlanması için sürekli havalandırma zorunludur. Yeraltında havalandırma; çalışma ortamının güvenliği için ocak sıcaklığını optimum seviyeye ayarlamak, zararlı gazların konsantrasyonunu yönetmeliklerle belirlenmiş değerler altında tutmak ve ocaktan tahliyesini sağlamak, çalışan personel ve makineler için gereken oksijen derişikliği yüksek temiz havayı temin etmek için yapılmaktadır.Bu çalışmada örnek bir kömür madeni 3 boyutlu olarak tasarlanmış, tüm kesit alanları ölçülmüş ve kömür üretim panoları incelenmiş, minimum ve maksimum hava hızları Maden Emniyet Tüzüğü'nce belirlenen sınır değerler içinde tutulmuş ve her bir noktadaki temiz hava miktarı bulunmuştur. Örnek maden işletmesinde ortaya çıkabilecek boğucu, zehirli, patlayıcı özellikteki tüm gazların emniyet sınır değerlerine detaylı olarak yer verilmiştir. Tehlikeli gazların derişime göre, insan sağlığı üzerindeki etkileri ile patlama riskleri detaylı olarak ele alınmıştır. Havanın kirlenme derecesi; kömürün oksijen ile reaksiyona girme potansiyeline, içerdiği gaz miktarına, uygulanan üretim yöntemine doğrudan bağlıdır.Maden havasını kirleten en önemli diğer unsurlar da kömür ve taş tozlarıdır. Yeraltı madenciliğinde hazırlık, üretim, doldurma, boşaltma, kırma, eleme ve nakliye çalışmaları sırasında cevher ve yan taşın özelliklerine bağlı olarak toz oluşmaktadır. Kömür tozu konsantrasyonuna bağlı patlama riskleri ile taş tozlarının sağlık üzerindeki olumsuz etkileri ve alınabilecek önlemler detaylı incelenmiştir.Örnek kömür madeninde öncelikle üretim hattı tüm yönleriyle ele alınmış ve pano uzunlukları ve ayak genişliklerine göre üretim yöntemleri açıklanmıştır. Maden içerisinde kömür nakliyatı vagon ve ray sistemi ile yapılmaktadır. Kömür damarı kalınlığına göre kesitler değişim göstermektedir. Uzun ayak sistemi ile kömür üretimi yapılmakta, başyukarılardan kömürün eğim sayesinde akması ve vagonlara doldurularak yerüstü eleme sistemine gönderilmesi sağlanmaktadır. Tüm bu çalışmalar süresince yeraltında çalışan tüm işçilere gerekli temiz havayı sağlamak adına havalandırma planlaması yapılmalıdır.Yeraltı madenleri için gerekli hava miktarı tayini yapılırken 5 yöntem ön plana çıkmıştır. Bunlar, işçi sayısına göre hava miktarının belirlenmesi, günlük üretime göre hava miktarı hesabı, maden içerisinde yayılan gazların hacmine göre hava miktarı tayini, ocaktaki toz oluşumuna göre hava miktarı hesabı ve patlayıcı miktarına bağlı hava miktarı hesabıdır. Sketch Up programı yardımı ile tasarlanan maden haritası VENTSIM programına aktarılmış, farklı kesit alanları, çeşitli çalışma koşulları ve toz konsantrasyonları dikkate alınarak optimum temiz hava hesaplamaları yapılmıştır.

Ventilation in underground mining; this is the most important operation for the employees to be in healthy working conditions and for the safe and long-lasting operation of the required machines. Continuous ventilation is essential for breathable air supply for the employees, the risk of explosion in the environment and the concentration of dust under control, according to the working method used by taking into account the physical activities of the employees to ensure proper air conditions. Underground ventilation, for the safety of the working environment, the temperature of the mine is adjusted to the optimum level, to keep the concentration of harmful gases under the values determined by the regulations and to discharge from the mine, to provide the high oxygen fresh air required for the working employee and machines.In this direction, the sample coal mine was designed in 3 dimensions, all cross-sectional areas were measured, the minimum and maximum air velocities were determined within the limit values determined by Mines Safety Regulation and the amount of fresh air at each point was found.The safety limit values of all the gases with explosive, toxic and explosive properties that may occur in the sample mining facility are detailed. According to the concentration, the effects of hazardous gases on human health and explosion risks are discussed in detail. The degree of air pollution; it directly depends on the potential of coal to react with oxygen, the amount of gas it contains, the method of production applied.The other most important elements polluting the mine air are coal and stone dust. During the preparation, production, filling, unloading, crushing, screening and transportation works in underground mining, dust is formed depending on the properties of the ore and side stone. Explosion risks due to coal dust concentration, negative effects of stone powders on health and precautions to be taken are examined in detail.Coal transport within the mine is carried out by coal wagon and rail system. The sections vary according to the thickness of the coal core. Coal production is carried out with the long foot system and coal is flowing through the slopes and filled into the wagons and sent to the surface sieving system. During all these works, ventilation planning was carried out to provide the necessary fresh air to all workers working underground.There are both stone and coal dust and many harmful gases in mine. Therefore, when calculating the need for clean air, both the dust concentration and the harmful gas emission must be calculated. In addition, the use of explosives should be examined. The degree of air pollution; it depends on the potential of the ore to react with oxygen, the amount of gas contained in the ore, the mine extraction method applied, the amount of air sent to the underground networks, the type of machinery used in the quarry and the dimensions of the working area.While determining the amount of air required for underground mines, 5 methods came to the fore. These are air quantity calculation according to the use of workers, air quantity according to daily production, determination of air volume according to the volume of gases emitted in the mine, air account calculation according to dust formation in the quarry and air account calculation based on the amount of explosives.While the air requirement is calculated by the number of workers working underground, the different physical conditions of the workers are classified according to ASHRAE standards. Workers working on the preparations of the gallery and supporting the fortification by lifting both the digging shovel and the mining pole and doing hard work almost without interruption as Group 1, workers working in the upstairs and producing coal with the help of digging shovels or by the help of marticipers as Group 2 and crane workers, wagons and hook and loop workers, who deal with a wagon shipment on average every three minutes with a relatively mild physical activity compared to other employees are classified as Group 3.If methane is considered as the most dangerous gas in the hearth air, air velocity control should be made according to the stratification condition in the ceiling sections. The lowering of the air velocity in the gallery wall and the increase of the methane gas, whose density is low compared to the air, towards the ceiling of the excavation cavity causes high concentration of methane in these regions. Air requirement is calculated by the methane concentration. Lastly air requirement is calculated by the dust concentration. There is a dry hole drilling operation in the mining facility in the preparatory gallery works, which continue between -1300 and -1260 levels. Drilling is done in 3 different heads above. Between levels -1385 and -1365, the rear of the pig roof is made upside down.In classical calculation methods, the friction coefficient is calculated for each tunnel based on the tunnel cross-section area and its surroundings and tunnel length, and then the required fresh air for the mine is tried to be found. However, this is both laborious and difficult to update.In our country, recycled or advanced longwall method is applied in underground coal enterprises in general. In these methods, a single-entry turning 'U' type ventilation system is used, fresh air enters the panel from the material gallery, and the contaminated air gets out of the transportation route and is connected to the main ventilation gallery.Although there is no limit on the maximum air velocity in longwalls in underground coal mines, air speed should not exceed 8 m/s on main airways, inclined and straight roads and should not be less than 0.5 m/s in any case. High air speed negatively affects worker health and the quarry climate. As a general rule, it is recommended that the settled dust swirl with increasing air velocity and keep it within the limits of 1-3 m/s and not exceed 4 m/s, in case of the possibility of mixing in the mine air again.The VENTSIM program calculates the air flows for each gallery using the Kirchoff Laws in its complex mine structure. The mine map, which was designed with the help of Sketch Up program, was transferred to the VENTSIM program and optimum clean air calculations were made by taking into consideration different cross-sectional areas, various working conditions and dust concentrations. Computer aided ventilation analysis is of great importance for all closed businesses in terms of both worker health and safety and accident risks. In this way, material losses are prevented by design and calculations. Effective planning is essential to prevent deaths due to insufficient air and hazardous gases.