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ABSTRACT The bore holes are usually analyzed by RQD method in the rock engineering practice. The limitation of this method mentioned by several authors: for example, RQD=0% (where the joint intercept (distance between the joint in the drill cores) is 10 cm or less), or RQD=100%, the RQD gives no information of the core pieces. It does not matter whether the discarded pieces are earth-like materials or fresh rock pieces up to 10 cm length. At the beginning of 2003, more than 3,000 meter long boreholes were analyzed parallel by two different methods: the traditional RQD and the C-method, introduced by Hansagi. According to the results, in case of very good or very poor core drill, the C method shows the jointing patterns better than the RQD method. The goal of this paper is to present the C-method and their advandages/disadvandages. Linear regression was found between the values between 10%< RQD< 90%, but the C value is much more sensitive, than the RQD. 1 INTRODUCTION In geotechnical engineering it is very important to know the surrounding soil and rock masses. In rocks the most useful are the rock mechanic properties. To get these drills should be made and the core should be gained from it intact. By getting a piece of the rock as it was in the original stat we can examine the jointing, the in fills, the weathering and a lot more. For the strength of the rock and deciding about the level of support the knowledge of the jointing is the most relevant. The RQD and the C methods are to make this property numerical. After presenting the two methods, the comparison is based on the drill data of preliminary exploration of the site of the Radioactive Repository at Bataapati. The data was given by Mecsekerc Ltd. RQD and C was always calculated at every drill.The calculationswere made by the same person therefore the subjective mistake can be regarded as constant. After several investigations the Central Hungarian Móragy basin was chosen for low and medium radioactive waste final disposal facility. The average high of the hilly land, which is covered by mostly forest, is around 260–280 above sea level while the deepest points of the valleys are approximately 160–170m above sea level. The strata of the area can be easily described although highly jointed by tectonic influenced. The main stratum is the Palaeozoic granite from the carbon time. The upper part of this stratum (more than 10 meters) is differently weathered. Above this about 50–60mthick Pleistocene loess can be found (Galos et al. 2002). The allocated area (approximately 300×600 m) firstly was investigated with geophysical methods before the bores were carried out till different depth (300–500 m). In this comparison more than 3,000 meters of core from 20 drills are used to make the statistics to show the relation ofthem clearly.