Etibakır Küre İşletmesi Yeni Maden Sahasının Jeolojik Ve Jeomekanik Yer Altı Modellemesi

Abstract

Kastamonu ilinin Küre ilçesinde Etibakır A.Ş.& Cengiz Holding tarafından işletilen Küre havzasında bulunan cevher sahasında yapılan sondajlar ile yeni bir cevher varlığı tespit edilmiştir. Maden rezervinin bir kısmı üretim faaliyeti tamamlanmış olan Bakibaba açık ocağının altında bulunmaktadır. Bakır rezervi 700 m kotu ile 270 m kotu arasında yer almaktadır. Bu çalışmada Bakibaba açık ocağı ve çevresinde cevher arama amaçlı yapılmış olan 123 adet sondaj verisinden faydalanılmıştır. Bu sondajlardan oluşturulan 33 adet jeolojik kesit değerlendirilmiş ve Etibakır A.Ş. tarafından 700 m, 600 m, 500 m, 470 m,400 m, 300 m ve 270 m olarak belirtilen yeraltı üretim katlarına karışılık gelen derinlikler için cevher geometrisini gösteren kat haritaları oluşturulmuştur. Yeraltı ocak tasarımında faydalanılmak üzere 700 m, 650 m, 600 m, 550 m, 500 m, 470 m, 450 m, 400 m, 350 m, 300 m ve 270 m kotları için jeolojik ve jeomekanik kat haritaları hazırlanmıştır. Cevherin ve yan kayaçların her bir üretim katı ve ara kat için üç boyutlu jeolojik modellemesi yapılmıştır. Jeolojik modelde öncelikle cevher geometrisi çıkarılmış daha sonrasında cevher-yan kayaç ilişkisi gösterilmiştir. Cevher Liyas yaşlı Küre formasyonuna ait bazaltik kayaçlar içerisinde disemine olarak ve bazaltlar ile siyah şeyller arasında da masif olarak bulunmaktadır. Cevherin yayılımı kuzeydoğu güneybatı yönündedir. Bu çalışma sonucunda 700 m ve 270 m kotları arasında kalan bölge için cevher geometrisini, cevher-yan kayaç ilişkisini gösteren 11 adet jeolojik kat haritasının birleştirilmesi ile yeraltının üç boyutlu jeolojik modeli elde edilmiştir. Jeolojik kat haritalarının yanı sıra her bir üretim katı ve ara katlar için cevher, taban taşı, tavan taşı ve yan kayaçların sağlamlık derecelerini gösteren jeomekanik kat haritaları oluşturulmuştur. Jeomekanik değerlendirme için öncelikle RQD verilerinden faydalanılarak arazinin RQD dağılım haritası oluşturulmuştur. B-131, M-261 ve M-262 araştırma kuyularından üretim katlarına karşılık gelen derinliklerden numunler alınarak mekanik ve fiziksel özellikleri belirlenmiştir. Numuneler üzerinde tek eksenli basınç, endirek çekme ve üç eksenli basınç deneyleri yapılmıştır. Arazi için Müller, RMR, Q ve İTÜ, MJKM Vardar kaya sınıflamaları yapılmıştır.Yapılan kaya sınıflamalarına göre çalışma alanı genel olarak zayıf ve orta kaya niteliğindedir. Kayanın in-situ parametrelerini belirlemek için İTÜ, MJKM Vardar sınıflaması, Hoek-Brown yenilme kriteri ve Leon Hipotezi uygulanmıştır. Arazinin RQD, RMR değerleri için üretim katları ve ara katlar için 11 adet dağılım haritası oluşturulmuştur. Daha sonrasında RQD, RMR ve dayanım özelliklerinin bir arada değerlendirildiği jeomekanik kat haritaları oluşturulmuş ve zayıf zonlar belirtilmiştir. Sonuç olarak oluşturulmuş olan jeomekanik modelde arazinin siyah şeyllerin bulunduğu batı kesimleri çok zayıf kaylardan oluşmkatadır. Arazinin doğu bölgesinde bulunan bazaltlar cevherleşme dolayısıyla yoğun hidrotermal alterasyona uğradıkları için zayıf niteliktedir.

Küre copper mine area have been an important place since ancient times for mining operations. In particular around the Bakibaba mine area the presence of over 2 million tons slag, and old gallery of old supports proofs old mine operations.Mine area was purchased in 2004 by Cengiz Holding. Between 2005-2009, 2,527,173 tons of ore produced open pit mine production activity in the Bakibaba open pit and production has been completed. A new ore have been identified with the drillings in Kastamonu, Küre, Bakibaba mine area. Some parts of mineral reserve loceted under Bakibaba open pit region and copper reserves is located in the region between of 270 m to 700 m level. Geological units in the study area are Liassic Küre Formation basalts and black shale. Copper mineralization in Küre mine area takes place in Küre formation of basaltic rocks. As the ore are massive and disseminated in basalts. Mineralization in the region as a result of intense hydrothermally altered basalts. For remove the new copper mine decided to build deep shaft on east of the Bakibaba open pit. In addition to this lowest elevation in the study area is 1000 m and the highest elevation of 1260 m. 700 m, 600 m, 500 m, 470 m, 300 m and 270 m elevations were determined as a layer of underground mining By Etibakır Inc. For the design of the underground quarry both engineering geology and rock mechanics and geological features should be identified. In underground mining galleries, ventilation shafts, ramps, shipping routes and all engineering designs, such as production floors of the geometry of the ore, the ore-wall rock association, ores and rocks stability is very crucial. Construction elements that make up the operation of the underground mining of ore rock to put the relationship under appropriate conditions, the ore position, shape, size, hydrogeological data, mineralogical properties of rocks, faults, discontinuities, underground cavities, such as the many geological data utilized to determine the regions where it crushed zones. In this study, geological and geomechanical layer maps were created of the area which located between 700 m to 270 m. And then three-dimensional modeling made of the ore and the side rocks in order to take advantages for the underground mining activities. Model of the geological structure of the land was formed and created the model to see the extent of the ore. In this study underground mining method selection of the factors that affect the geometrical properties of the bed, geological conditions and geotechnical properties were determined. 33 number of cross section images data that were created with 123 drill holes which have been utilized. The geological datas were related to each other thanks to data of boreholes. Showing the extent of the ore to depths corresponding to the firstly layer of the production layer maps. Then, for a better view of the relationship between the ore-wall rock which are the intermediate layers of 650 m, 550 m, 450 m and 350 m and the production layers geological maps were formed. Also, 11 maps are prepared in 1/2000 scale in 400 m * 700 m which cover an area of 28 000 m . As a result of this study layers between elevations of 700 m and 270 m for the region, the geometry of the ore, the ore-wall rock geological layer of 11 maps showing the relationship of the three-dimensional geological underground modelings. These modelings were made with the help of 11 maps. The ores are usually associated with faults along the black shale-basalt contacts that are always involved in this case the sequence of basalt ores. Ores have been disseminated in altered basaltic rocks around the location of massive ore bodies. The contact zones of disseminated ore has different spills. The geological modeling of ore is seen that the NW-SE extension. Descend to 270 m the upper elevations of northeast is spreading to the southwest. The black shales which has bed quality rock in the western region of the land. Besides, basalts are in the parts of eastern region. The black shale forms a boundary almost all depth of with ore. In addition to the geologic model of area geomechanics maps were prepared for each production and middle layers in Bakibaba. Geomechanics model were created with maps for each layer on the ore, base stone, roof stone and the side of rocks which shows the degree of stability of rocks. Firstly RQD data was used to determine the geomechanical proporties of study area. For each production layers was created for RQD distrubition maps. RQD values are generally between 25% - 60%. Some parts of area are fractured however in some parts are highly fractured. Weak and strong zones are shown us for the specified depths on three-dimensional geomechanical model. Core samples were taken from depth of production layers in B-131, M-261 and M-262 research wells to determine the mechanical properties of area. Mechanical properties of rock were determined by rock mechanics testing. Triaxial compression strength, indirect tensile strength and uniaxial compression strength values were determined by laboratory testing. Also elastic parameters were determined with tensile-deformation graphics. Mohr envlopes were drawn by results of triaxial compression tests and then cohesion and friction angles values were found. According to the data of the M-261 well, the well has average 42,31 MPa uniaxial compressive strenght and fair strenght rocks. Very low uniaxial compression strenghts have been obtained from the shallow parts of the well. According to the data of M-262 well uniaxial compressive strength data rocks are poor and fair strength. Obtained from the testing for three wells and maximum compressive strength 94.57 MPa, while the lowest value is 6.37 MPa. Cohesion values varies in direct proportion to the uniaxial compressive strength. Underground rock explosions, roof falls, understanding of problems such as openings, closings and control of strength the heels of the rock at the side of the excavation to be carried out with sufficient information about the strength and deformation behavior of rock. Therefore, stress-strain graphs were created with the uniaxial compressive strength values. Merger of increased micro-discontinuities and fracture causes to translation on main discontinuity. Physical properties which are saturated unit weight, dry unit weight, porosity, water absorption and the vacancy rate values were determined. In this study, Müller rock mass classification, Q rock classification and RMR rock mass classification were made: For the classification of Müller, discontinuity measurements were made the surface. The most important feature of the Müller rock classification is to taking into account the size of system. According to Müller classification rock setting is weathered rock. According to the Q classification of rock setting is weak and very weak. RMR value of the side is generally between 40-60 on levels. Particularly middle and poor quality rocks are seen in the area. There are very poor rocks especially in west part of area. Stone is derived from laboratory tests, the mechanical properties of the rock do not apply to the numerical values of rock. These values must be reduced according to the environment condition of discontinuities, the type and anisotropy of rock. To determined the mechanical properties of the rock, the results of in-situ measurements, similar experiences and empirical formulas are used in environments previously acquired. In order to find the parameters of rock mass, İTÜ, MJKM Vardar classification and Heok-Brown failure criterion was used. According to Heok-Brown failure criteria, obtained very high values. Therefore, cohesion values were calculated with the Leon hypothesis. Leon hypothesis and the İTÜ, MJKM Vardar classification results are close to each other. In study area, RQD, RMR values distribution maps were created 11 number of maps for intermediate leyars and production layers. Then, RQD, RMR, and evaluated a combination of strength were created geomechanical layer maps. Weak and strong reagion were shown on maps. Conseqently, all results of geologic and geomechanics data correlated each other. The design of the underground quarry should be avoided the western regions where black shales are found. Rocks in the northern part of the land is well qualified than other regions.