Crown Pillar Optimization for Surface to Underground Mine Transition in Erzincan Bizmisen Iron Mine

Legal license boundary restrictions and economic considerations for extraction of vein type iron orebody in Erzincan/Bizmişen area of Turkey limit the overall production by open pit mining. Based on overall Stripping Ratio (OSR) assessments, ore production is decided to proceed by open pit mining to a certain depth and continue with a cut and fill type underground mining operation. A crown pillar is to be designed in the transition region from surface to underground operations. Crown pillar dimensioning effects the overall ore recovery in such small-scale ore bodies. Proper dimensioning has to ensure the stability of open pit mine slopes and underground mine structural units as underground mining progresses to upper levels. Dimensional optimization of the crown pillar is performed by empirical, deterministic and numerical modeling approaches. First, scaled span method was employed to estimate the safe crown pillar thickness providing the required service life. Later, rigid analysis method was used to check shear type failure from the abutments. Finally, 2D finite element modeling analysis was used to ascertain the stable crown pillar thickness. Input parameters of numerical models were produced from geotechnical site investigation work and laboratory experiments. Disturbance effect of surface mine production blasting on the slopes of rock mass above the underground workings was taken into account in deciding on the rock mass properties

Slope stability risk assessment on structures of a nearby residential area around a surface lignite mine in Bursa-Turkey

Slope failures may cause production interruption and equipment loss in addition to the potential danger for personnel. A potential instability in parts of the slopes near residential areas may result in damage on the surface utility structures as well as legal issues. In Orhaneli Surface Lignite Mine, Altintas village is located close to the existing southwest slope of Panel SA-6 in Sagirlar Sector. South-east slope which is also near Altintas village had some slope stability problems. Safe and uninterrupted future production in Sagirlar SA-6 panel and assessment of the preventive measures to protect the structures of Altintas Village are the main targets in this work. Potential for a possible slope failure and its effects on structures of Altintas village are assessed and some remediation measures are proposed. Remediation suggestions are predicted to increase safety against effects of a potential slope failure. Potential risks are evaluated by means of comparing safety factors which are determined by modeling the different slope geometries and preventive measures with a program using limit equilibrium methods. Slope stability analyses in this work are conducted by Rocscience SLIDE program which is a method of slices program based on the limit equilibrium techniques. Optimum slope geometries for different production directions and alternatives are investigated and alternative solutions for the improved safety of mine operations and nearby structures of Altintas Village are assessed

An Investigation of Rock Properties and Environmental Safety Aspects for the Design of an Underground Asphaltite Mine in Southeast Turkey

The paper describes the findings of research which was concerned with the possible development of an underground mine at Harbol vein in the Cizre-Silopi area. The mechanical and physical properties of asphaltite and the surrounding rock units are determined and their cuttabilities assessed. The liability of asphaltite to spontaneous combustion is examined and the volume and composition of gases stored in the asphaltite are determined. The environmental effects of self heating and gas emissions are discussed and recommendations are made