ABSTRACT: A plant will be constructed between the Alipasa and Sarıkısık feldspar open-pit mines in Karpuzlu-Çine(Aydın) to conduct the works of crushing-grinding and flotation. An investigation was carried out to determineengineering geological conditions at and below the plant-site using scan-lines, geophysical measurements, and threeinclined borehole data. Geological structure and ground conditions including geotechnical data such as discontinuityfrequency and spacing, RQD% and CR% acquired from the drill hole exploration and geophysical survey aredetermined. Along the inclined drill holes, true discontinuity spacing values computed for each core run representthe most intersected discontinuities. In these calculations, determination of the acute angles between the axes ofdrill holes and strikes of the discontinuity sets are important as much as the investigation of fracture distributions inthe subsurface. For this reason, the stereographic projection techniques were used to determine the true acute anglein this work. The purpose of the investigation is to identify and mitigate difficulties caused by ground conditions.The rock conditions comprise heavily jointed and weathered metamorphic rocks and the ability of these to supportthe foundations is considered. It was determined that the bearing capacity values obtained from the geotechnicalcomputations considering RQD values agree with the ones acquired from the geophysical measurements, except theweakness zones (sheared zones). It was also determined that the values of allowable bearing pressure based on thegeotechnical works are more conservative than the ones from the geophysical measurements. When all results areconsidered, the ratio between the allowable bearing capacity (qa) values acquired from geotechnical and geophysicalmeasurements is close to 0.65.