Bir altın madeninde yeraltı üretim geometrilerinin ve tahkimat sisteminin jeoteknik esaslara göre belirlenmesi
Determination of underground production geometries and support system in a gold mine according to geotechnical principles
Yazar: FATMA ZEHRA TOKER
Danışman: DOÇ. DR. CÜNEYT ATİLLA ÖZTÜRK
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Maden Mühendisliği Ana Bilim Dalı / Maden Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2024
Konu: Maden Mühendisliği ve Madencilik = Mining Engineering and Mining

Özet:
Altın, dünya ekonomisinde önemli rol oynayan değerli bir metaldir. Yeraltı madenciliği bu metali elde etmenin en yaygın yöntemlerinden biri olup üretimin güvenli ve sürdürülebilir bir şekilde yürütülebilmesi için kaya mekaniği ve jeoteknik prensiplerin dikkate alınması çok önemlidir. Bu bağlamda yeraltı maden işletme yöntemine uygun olarak ihtiyaç duyulan üretim geometrilerinin jeoteknik yapıya uygun şekilde belirlenmesi, doğru zamanda yerleştirilen doğru tahkimat sisteminin kullanılması ve arazi kontrol prensipleri aynı şekilde büyük önem arz etmektedir. Bu çalışmada, bir yeraltı altın madeni üretim yönteminin kaya mekaniği ve jeoteknik ilkeleri doğrultusunda değerlendirilmesi yapılarak, madencilik faaliyetlerinin güvenli ve sürdürülebilir bir şekilde yürütülmesine katkıda bulunulması amaçlanmıştır. Gizlilik esasları sebebiyle sahaya ilişkin veriler, tez kapsamında kısmi olarak paylaşılmıştır.
Çalışma kapsamında öncelikle bir altın madeni bölgesinde yer alan çalışma alanının jeolojik yapısı, bölgesel jeoloji ve yapısal jeoloji açısından değerlendirilmiştir. Bu bağlamda, ilk olarak çalışmada yeraltı açıklıklarının tahkimatı ve üretim boyutları parametrelerinin belirlenmesi üzerine çalışılmıştır. Tahkimat tasarımları üretim galerileri için gerçekleştirilmiştir. Her litoloji için 5 m açıklıklar dikkate alınarak Q değerlerine göre tahkimat sınıfları belirlenmiştir. Sonrasında, yeraltı tasarımı üzerinden litolojiye ve açıklığın kullanım amacına uygun olarak tahkimat tasarımları gerçekleştirilmiştir. Analitik çalışmalar ile üretim galerilerinde 1 no'lu tahkimat sınıfı uygulaması sonucu elde edilmiştir.
Yeraltı madencilik faaliyetlerinde optimum üretim ve güvenlik faktörleri göz önünde bulundurulduğunda, tahkimat uygulamalarının yanı sıra üretim boyutlandırmaları da stabiliteyi sağlama aşamalarından biridir. Bu çalışmada, altın madeni yeraltı çalışmaları kapsamında üretim geometrileri jeoteknik yapıya göre boyutlandırılmıştır. Ara katlı dolgulu üretim yöntemi dikkate alınarak, analitik çalışmalar ile üretim bacasının tasarımı ve boyutlandırılması gerçekleştirilmiştir. Q değeri dikkate alınarak, farklı pano boyları için her bir litolojik birim değerlendirilmiştir. Bu çalışmada, 30 m, 50 m, 80 m, 100 m, 150 m ve 200 m pano boyları üzerinde çalışılmıştır. Ayrıca, üretim uzunluğuna karar vermek için de benzer bir çalışma yapılmıştır. Bu değerlendirmeler sonucunda, 50 m pano uzunluğu ve 5 x 5 m üretim açıklıkları için 15 m üretim uzunluğu ve üretim yüksekliği uygun görülmüştür.
Bu sonuçlara bağlı kalarak oluşturulan nümerik analizler, yeraltı altın madeni üretim faaliyetlerinin güvenliğini ve verimliliğini artırmak amacıyla gerçekleştirilmiştir. RS2 programı kullanılarak yapılan bu analizlerde, seçilen üretim yöntemi, üretim bacalarının boyutları ve tahkimat sistemlerinin performansı detaylı bir şekilde incelenmiştir. Nümerik analizler, kaya kütlesindeki gerilme ve deformasyon dağılımlarını, tahkimat sistemlerinin dayanıklılığını ve potansiyel tehlikeleri simüle ederek, üretim sürecinin güvenli ve sürdürülebilir bir şekilde yönetilmesine olanak tanımıştır. Bu sayede, madencilik faaliyetlerinde karşılaşılabilecek riskler minimize edilerek, optimal üretim koşullarını sağlayacak senaryolar türetilip çalıştırılmıştır.

Abstract:
Gold is a valuable metal that has major significance in the global economy. Underground mining is a common technique for extracting this metal, and it is crucial to incorporate rock mechanics and geotechnical concepts to ensure safe and sustainable production. In this context, it is equally important to determine the production geometries required for underground mining operations based on the geotechnical structure, utilize the appropriate support system at the correct timing, and follow to the principles of ground control. The research aims to improve the safety and sustainability of mining activities by evaluating an underground gold mining production technique based on rock mechanics and geotechnical concepts. Due to confidentiality concerns, only a portion of the data related to the field has been disclosed in the thesis.
The research evaluated the geological composition of the region, in relation to both regional geology and structural geology. The geotechnical database was established through comprehensive geotechnical drilling and rock mechanics experiments conducted in the ITU Mining Engineering Department's laboratories. These drilling operations, with a total length of 3090 meters, provided critical data on the underground geotechnical conditions. Analysis of the lithological distributions highlight the dominance of the volcanoclastic unit in the field.The rock mechanics experiments included tests to determine intact rock properties, such as unit volume weight, elastic modulus, cohesion, internal friction angle, and tensile strength. Additionally, underground face mapping forms were used to obtain Q, RMR, and Q' values. These values were crucial for assessing the quality and stability of the rock mass in various sections of the mine. The Q values, which represent the rock mass quality, the Rock Mass Rating (RMR), and the Q' values, a modified version of the Q-system, were all derived from detailed face mapping and field observations. 
Within this particular context, the study was primarily concerned with the determination of the appropriate dimensions for production layouts. Support designs were created specifically for the purpose of production galleries. The support classes for each lithology were derived based on the Q values, considering 5 m openings. Support designs were subsequently implemented to align with the objectives of lithology and to enhance transparency in the underground design. The designs in support class number 1 have been developed in the production galleries.
When optimum production and safety factors are taken into account in underground mining activities, arbitration practices as well as production dimensioning are one of the stages to ensure stability. In this study, the production geometries were dimensioned according to the geotechnical structure. The design and dimensioning of the production basin has been carried out with analytical studies, taking into account the stability graph method. Each litological unit was evaluated for different panel lengths, taking into account the Q value. In this study, 30 m, 50 m, 80 m, 100 m, 150 m and 200 m panels were studied. A similar study has also been conducted to determine the length of production. As a result of these evaluations, a production length of 15 m and a production height of 5 x 5 m were found to be suitable for the 50 m panel length and production openings.
Based on these findings, numerical analyses have been carried out to improve the safety and efficiency of underground gold mining activities. Numerical analyses using the RS2 program, have enabled the production process to be managed safely and sustainably by simulating the distribution of tension and deformation in the rock mass, the durability of the control systems and the potential hazards. 
Numerical analyses conducted using the RS2 program simulated the effects of the support system on the rock mass, evaluating various production sequences and stope spacing scenarios. These analyses are critical for assessing the effectiveness of different design and operational strategies aimed at enhancing safety and efficiency in underground mining.
The results indicate that, in the existence of support system, deformations around the gallery decreased from 6.8 cm to 1.3 cm, representing a reduction of approximately 80%. This significant finding clearly demonstrates the effectiveness of the support system in ensuring the stability of underground galleries. Particularly, the substantial reduction in deformations when support is applied underscores its vital role in maintaining the safety of mining operations. When evaluating production sequences, it was observed that the model where production starts from the middle of the stope exhibited lower maximum displacement values. This finding justifies information from the literature and provides an important reference point for determining the optimal production sequence. Starting production from the middle of the stope minimizes the impact of induced stresses, thereby reducing deformations around the gallery. This strategy enables a more controlled and safer progression of the production process. In scenarios involving stope spacing, it was determined that a 15-meter spacing resulted in lower displacement values compared to a 5-meter spacing, providing safer working conditions. The lower deformations observed at the 15-meter spacing indicate its advantages in terms of operational safety and efficiency. This spacing facilitates a more even distribution of stresses on the rock mass, thereby reducing the risk of deformation.
In light of these results, it has been determined that the optimal solution involves starting production from the middle of the stope and maintaining a stope spacing of 15 meters. This strategy ensures both safe working conditions and increased operational efficiency. However, considering different scenarios and parameters, the scope of the study can be expanded and supported by more detailed analyses. For instance, taking into account different rock mass properties, variable support systems, and alternative production sequences would provide a more comprehensive and holistic approach.
In the context of underground mining, validating analytical studies with numerical analyses is of paramount importance. Analytical methods provide initial estimates and conceptual models that guide the design and planning stages. However, these methods often rely on simplifications and assumptions that may not fully capture the complex behaviors of rock masses under various stress conditions. Numerical analyses, on the other hand, offer a more detailed and precise representation of the underground environment by incorporating real-world data and sophisticated computational techniques. By validating analytical results with numerical simulations, it can be ensured that the design parameters are robust and reliable, thereby minimizing risks associated with unforeseen ground behaviors. This combined approach enhances the accuracy of stability assessments, optimizes support systems, and ultimately contributes to safer and more efficient mining operations. Such rigorous validation processes are essential for addressing the inherent uncertainties in underground mining and for achieving sustainable and resilient engineering solutions.
In conclusion, this study presents significant findings aimed at enhancing safety and optimizing production conditions in underground mining operations. Numerical analyses conducted using the RS2 program evaluate the effectiveness of support systems and production strategies, providing valuable insights for safer and more efficient mining operations. These findings serve as a guide for future research and applications in the field of underground mining.