EVALUATING THE SAWABILITY OF ROCKS BY CHAIN-SAW MACHINES USING THE PROMETHEE TECHNIQUE

One of the most significant factors in the estimation of dimension stone quarry cost is the production rate of rock cutting machines. Evaluating the production rate of chain-saw machines is a very significant and practical issue. In this research, it has been attempted to evaluate and select the suitable working-face for a quarry by examining the maximum production rate in the Dehbid and Shayan marble quarries. For this purpose, fi eld studies were carried out which included measuring operational characteristics of the chain-saw cutting machine, the production rate and sampling for laboratory tests from seven active case studies. Subsequently, the physical and mechanical properties of rocks including: Uniaxial Compressive Strength (UCS), Brazilian Tensile Strength (BTS), Los Angeles abrasion, quartz content, water absorption percentage, porosity, Schmidt hardness and grain size for all sample measurements were studied after transferring the samples to a rock-mechanics laboratory. Finally, the sawability of the quarried working-faces was evaluated using the PROMETHEE multi-criteria decision-making (MCDM) model according to the physical and mechanical properties. The results of the study indicated that the number 1 and 5 working-faces from the Dehbid and Shayan quarries are the most suitable working-faces in terms of production rate with the maximum recorded production values (4.95 and 3.1 m2 /h), and with net fl ow rates (2.67 and -0.36) respectively.

A Reliable PSO-based ANN Approach for Predicting Unconfined Compressive Strength of Sandstones

Background: The reliable determination of geomechanical parameters of rocks such as Unconfined Compressive Strength (UCS) using laboratory methods is problematic and time-consuming. In this regard, the construction of reliable predictive models for assessing the UCS is of advantage. Objective: The main purpose of this work is to propose the use of a reliable PSO-based ANN approach for predicting the UCS of sandstones. Methods: For this purpose, laboratory tests were performed on 60 sandstone specimens. The laboratory tests comprise P-wave velocity, dry density, Schmidt hardness and UCS. Apart from the latter, the other laboratory tests were set as model inputs. Prediction performance of the constructed model was assessed according to the criteria including coefficient of determination (R2), Root Mean Squared Error (RMSE) and Variance Account For (VAF). Results: Results (R2= 0.974 and RMSE = 0.086 and VAF = 97.5) showed the reliability of the constructed PSO-based ANN model to predict UCS of sandstones. Conclusion: Hence, this study recommends utilizing PSO-based ANN as a feasible tool for assessing UCS of sandstones. Nevertheless, further research is suggested for model generalization purposes.

Mechanical properties of some building stones from volcanic deposits of mount Erciyes (Turkey)

Mount Erciyes is a huge stratovolcano of the Central Anatolian province in Turkey and it has produced calc-alkaline and pyroclastic rocks, which have been widely used as dimension stone in low-storied buildings and especially in historical monuments in the past. In the region there are some 205 quarries extracting volcanic rocks. In this study, the locations of these quarries and information on their annual stone production are evaluated. In order to assess the material properties of the Mount Erciyes volcanic products, petrographic analyses and a number of rock mechanical tests were carried out. Significant correlations were found between the properties of the rock samples. In particular, there is a significant relationship between thermal conductivity and some non-destructive measurement values such as P-wave velocity, Equotip and Schmidt hardness, and it is clear from the regression equations that these tests can be used as indicators for evaluating the Mount Erciyes products.

Correlation of physical and mechanical properties with ultrasonic pulse velocities of sandstones in Çenedağ, Kocaeli-Turkey

Correlation of physical and mechanical properties with ultrasonic pulse velocities (UPV) of sandstones in Çenedağ, Kocaeli-Turkey, NW was performed in this study. Physical and mechanical properties were defined and the relationships among the uniaxial compressive strength (UCS), porosity, void ratio, point load strength index Is(50),Schmidt hardness (RN) and bulk mass density by weight with ultrasonic pulse velocity of pink and cream colored sandstone unit of Lower Ordovician Çenedağ formation were investigated. In the scope of this research, 16 sandstone specimens were collected from various locations of Çenedağ formation in Çenedağ-Kocaeli, Turkey and laboratory experiments were implemented. Later, the statistical correlations were performed by regression analysis to evaluate the relationships between these properties and ultrasonic pulse velocity. Reasonably good correlations were determined between the UPV and physical and mechanical properties.