Core Drilling of Borehole ONK-PVA4 in ONKALO at Olkiluoto 2007

Transcription

1 Working Report Core Drilling of Borehole ONK-PVA4 in ONKALO at Olkiluoto 2007 Esa Pohjolainen October 2007 POSIVA OY FI OLKILUOTO, FINLAND Tel Fax

2 Working Report Core Drilling of Borehole ONK-PVA4 in ONKALO at Olkiluoto 2007 Esa Pohjolainen Suomen Malmi Oy October 2007 Working Reports contain information on work in progress or pending completion. The conclusions and viewpoints presented in the report are those of author(s) and do not necessarily coincide with those of Posiva.

3 CORE DRILLING OF BOREHOLE ONK-PVA4 IN ONKALO AT OLKILUOTO 2007 ABSTRACT Posiva Oy submitted an application to the Finnish Government in May 1999 for the Decision in Principle to choose Olkiluoto in the municipality of Eurajoki as the site of the final disposal facility for spent nuclear fuel. A positive decision was made at the end of 2000 by the Government. The Finnish Parliament ratified the decision in May The decision makes it possible for Posiva to focus the confirming bedrock investigations at Olkiluoto, where in the next few years an underground rock characterisation facility, ONKALO, will be constructed. The construction of the ONKALO access tunnel started in September As a part of the investigations Suomen Malmi Oy (Smoy) core drilled m long borehole ONK-PVA4 with a diameter of 75.7 mm in ONKALO in April-May A borehole was core drilled for long-term monitoring purposes in a place where no grouting is done. The deviation of the borehole was measured with the deviation measuring instrument EMS. The main rock types are diatexitic gneiss (DGN) and mica gneiss (MGN). The fractures are mostly filled. The average fracture frequency of the borehole is 1.1 pcs/m and the average RQD value is 99.4 %. Keywords: core drilling, borehole, diatexitic gneiss, mica gneiss, fracture, deviation measurements

4 REIÄN ONK-PVA4 KAIRAUS ONKALOSSA, EURAJOEN OLKILUODOSSA 2007 TIIVISTELMÄ Posiva Oy jätti valtioneuvostolle vuonna 1999 periaatepäätöshakemuksen, jolla se haki lupaa valita Eurajoen Olkiluoto käytetyn ydinpolttoaineen loppusijoituslaitoksen rakennuspaikaksi. Joulukuussa 2000 valtioneuvosto teki asiasta myönteisen päätöksen. Toukokuussa 2001 eduskunta vahvisti valtioneuvoston päätöksen. Periaatepäätöshakemuksen mukaisesti paikkatutkimukset keskitetään Olkiluotoon. Loppusijoituslaitoksen maanalaisen kallioperäntutkimustilan, ONKALOn, ajotunnelin rakentaminen aloitettiin Olkiluodossa syyskuussa Seurannalla pyritään myös selvittämään sementin vaikutusta pohjavesikemiaan eri etäisyyksillä tunnelista. Osana tutkimuksia Suomen Malmi Oy (Smoy) kairasi 15,00 m pitkän reiän (ONK-PVA4) ONKALOssa huhti-toukokuussa Reikä kairattiin pohjavesien pitkäaikaista monitorointia varten paikkaan, missä ei ole injektoitu. Reiän tarkoitus on tutkia rakentamisen aiheuttamia muutoksia pohjaveteen. Reiän halkaisija on 75,7 mm. Reiän taipumat mitattiin EMS -mittarilla. Pääkivilajeina esiintyvät diateksiittinen gneissi (DGN) ja kiillegneissi (MGN). Rakoilutyyppinä täytteiset raot ovat yleisimpiä. Kallion rakoluku on keskimäärin 1,1 kpl/m. RQD-luku on keskimäärin 99,4 %. Avainsanat: kairaus, kairanreikä, diateksiittinen gneissi, kiillegneissi, rako, sivusuuntamittaus

5 1 TABLE OF CONTENTS ABSTRACT TIIVISTELMÄ 1. INTRODUCTION Background Scope of the work DRILLING WORK AND TECHNICAL DETAILS OF THE BOREHOLE Diamond core drilling Deviation surveys Location and deviation Construction of the upper part of the borehole GEOLOGICAL LOGGING General Lithology Foliation Fracturing Fracture frequency and RQD Weathering Core orientation ROCK MECHANICS The rock quality SUMMARY REFERENCES APPENDICES 7.1 List of core boxes List of lifts Deviation surveys, list, EMS Petrographical description Degree of weathering Foliation List of fractures Fracture frequency and RQD Core orientation Q-classification PHOTOS... 45

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7 3 1. INTRODUCTION 1.1 Background In 1999, Posiva Oy submitted an application for the Decision in Principle to Finnish Government for a construction permit to build a final disposal facility for spent fuel at the Olkiluoto area in the Eurajoki municipality. In December 2000, the Finnish Government made a positive policy decision and in May 2001, the parliament ratified the Decision in Principle. The Decision in Principle makes it possible to concentrate the research activities at Olkiluoto, Eurajoki. One part of the research is to build an underground rock characterisation facility, ONKALO. The construction of the ONKALO access tunnel started in September Posiva Oy contracted (order number ) Suomen Malmi Oy (Smoy) to drill a borehole in the ONKALO. The identification number of the borehole is ONK-PVA4. A borehole was core drilled for long-term monitoring purposes in a place where no grouting is done. The objective with the borehole is to monitor the influences of construction at ONKALO. A borehole was core drilled in April-May Scope of the work The aim of the work was to drill a borehole related to the investigation programme on the influence of grouting in groundwater chemistry and monitor the influences of construction at ONKALO. The core samples were logged according to the geological instructions of Posiva. To maximise the recovery yield of an undisturbed and continuous core, triple tube coring technique was used. In addition to the drilling, work included core logging, borehole deviation surveys and reporting. This report documents the work and sampling done during the drilling of the borehole. Depth measurements are from the tunnel floor surface unless otherwise stated.

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9 5 2. DRILLING WORK AND TECHNICAL DETAILS OF THE BOREHOLE 2.1 Diamond core drilling The diamond drilling was done in April-May The borehole was started at tunnel floor. First the casing was drilled to the depth of about one metre into the bedrock. After the casing was drilled, diamond core drilling continued normally. Borehole was core drilled with a hydraulic Diamec U6 drill rig. NQ3 -triple tube core barrel and NQ-drill rods were used in drilling. Borehole diameter with NQ3 -triple tube core barrel is 75.7 mm and drill core diameter is 50.2 mm. After finishing the work, the casing was left in the borehole. After drilling, the Posiva Oy measured the amount of water flowing from borehole, which was under 10 mm/h. The cutting area of the diamond bit of the triple tube core barrel is larger than that of the double tube core barrel. In the triple tube core barrel the third, innermost, tube is of split type. The innermost split tube containing the sample is removed from the core barrel with the aid of a piston working on water pressure. In this way the sample may be removed from the core barrel as undisturbed as possible. Drilling team in a shift consisted of a driller and an assistant. Geological logging was done by geologists Esa Pohjolainen and Vesa Toropainen and the final report was compiled by Esa Pohjolainen. Drill core samples were placed in wooden core boxes immediately after emptying the core barrel. In total, four wooden core boxes were used during this drilling work. Start and end depths of the core in each core box are presented in Appendix Wooden blocks separating the different sample runs were placed to core boxes to show the depth of each lift. The core drilling included six sample runs or lifts. Depths of lifts are presented in Appendix Deviation surveys To trace the borehole accurately the dip and the azimuth of borehole were measured with EMS downhole deviation survey tool. Measuring interval was three metres.

10 6 EMS device measures the borehole dip with an electronic accelerometer and the azimuth relative to the magnetic north with a three component fluxgate magnetometer. According to the manufacturer, provided there are no magnetic anomalies, the accuracy of the azimuth is ± 0.5 degrees and the accuracy of the dip is ± 0.2 degrees. The azimuth is given to the magnetic north and the declination. There may be some local variations in the declination. Used declination in EMS calculations is 4.0 degrees. 2.3 Location and deviation The bedrock surface of the tunnel floor was used as the reference level for depth measurements. The initial dip of borehole is downwards, about -60 degrees from horizontal. The coordinates of the boreholes in the Finnish coordinate system are shown in Table 1. The collar coordinates were measured by the Posiva. The coordinates at the end of the borehole are based on the EMS data. The results of the EMS surveys are listed in Appendix 7.3. Table 1. Coordinates of the borehole. Station (m) X Y Z Construction of the upper part of the borehole The borehole was collared with 89/78 mm acid-resistant steel casing to the depth about one metre from the tunnel wall surface. When the borehole was finished, the casing was left in the borehole.

11 7 3. GEOLOGICAL LOGGING 3.1 General Handling of the core was based on the POSIVA work instructions POS Core handling procedure with triple tube coring (in Finnish). Drill core samples were placed in about one metre long wooden core boxes immediately after emptying the core barrel. Core boxes were covered with damp proofing quality aluminium paper so that the aluminium surface was against the core. Also the wooden blocks separating the different sample runs were covered by aluminium paper. Drill core was handled carefully during and after the drilling. Core was placed in the boxes avoiding any unnecessary breakage. The core logging of ONK-PVA4 followed the normal Posiva logging procedure, which has been used e.g. in pilot hole drilling programmes at Olkiluoto. Geologists Esa Pohjolainen and Vesa Toropainen carried out the geological core logging. From the core samples the lithology, foliation, fracturing, fractured zones, weathering and rock quality were mapped. All core boxes were photographed (colour) both dry and wet. Core photographs (wet) are presented at the end of the report. List of core boxes lists the start and end depths of the core in each core box (Appendix 7.1). List of lift depths is given as it has been marked on the spacing wooden blocks separating different sample runs in the core boxes. If the length of the core in the core barrel indicated that sampling depth was different from the depth recorded during drilling, the true sample depth has been corrected on the spacing block. Therefore, the sample run depth means the sample depth. The drilling depth might be deeper than the sampling depth if the core lifter slips and part of the core is left in the borehole and is not retrieved until with the next lift. 3.2 Lithology The lithological classification used in the mapping follows the classification by Mattila (2006). In this classification, migmatitic metamorphic gneisses are divided into veined- (VGN), stromatic- (SGN) and diatexitic gneisses (DGN). The non-migmatitic metamorphic gneisses are separated into mica- (MGN), mafic- (MFGN), quartz- (QGN) and tonalitic-granodioritic-granitic gneisses (TGG). The metamorphic rocks form a compositional series which can be separated by rock texture and the proportion of

12 8 leucosome. Igneous rock names used in the classification are coarse-grained pegmatitic granite (PGR), K-feldspar porphyry (KFP) and diabase (DB). The ONK-PVA4 drill core consists mostly of diatexitic gneiss (87.4 %). A section of MGN (12.6 %) occurs between m. The DGN is irregularly and weakly or moderately banded. The leucosome proportion in DGN varies between %, most of the rock being ca. 60 %. The feldspars are slightly kaolinitized and epidotized between m. The lithology recorded from the core is presented in Appendix Foliation Measurements on foliation were carried out in variable intervals from the core sample. A total of six observations on foliation were made. The classification of the foliation type and intensity used in this study is based on the characterisation procedure introduced by Milnes et al. (2006). Foliation type was estimated macroscopically and classified into five categories: MAS = massive GNE = gneissic BAN = banded SCH = schistose IRR = irregular The gneissic type (GNE) corresponds to a rock dominated by quartz and feldspars, micas and amphiboles occur only as minor constituents. Banded foliation type (BAN) consists of intercalated gneissic and schistose layers, which are either separated or discontinuous layers of micas or amphiboles. Schistose type (SCH) is dominated by micas or amphiboles, which have a strong orientation. The intensity of the foliation is based on visual estimation and classified into the following four categories: 0 = Massive or irregular 1 = Weakly foliated 2 = Moderately foliated 3 = Strongly foliated

13 9 The two variables (type and intensity) can be combined in a matrix, which is constructed to reflect the mechanical properties of the rock. Massive (MAS) corresponds to massive rock with no visible orientations and irregular (IRR) to folded or chaotic rock. The foliation type in the predominant rock type, DGN, is banded (87.4 %). A section of MGN between m consists of gneissic type (12.6 %). The most common foliation direction is towards southeast (150/40) as shown in Figure 3-1. Figure 3-1. Measured foliation orientations of ONK-PVA4 on an equal area lower hemisphere projection. Contours presented are 2, 5, 10, 20 and 30 %. 3.4 Fracturing The fractures were numbered sequentially from the top to the bottom of the borehole. Fracture depths were measured to the centre line of the core and were given with one centimetre accuracy. Each fracture was described individually and attributes include orientation, type, colour, fracture filling, surface shape and roughness. The J a (joint alteration) and J r (joint roughness) parameters for the Q-classification were also collected for each fracture. The abbreviations used to describe the fracture type are in accordance with the classification used by Suomen Malmi Oy (Niinimäki 2004), Table 3-1.

14 10 Table 3-1. The abbreviations used to describe the fracture type (Niinimäki 2004). Abbreviation op ti fi fisl grfi clfi Fracture type open tight, no filling material filled filled slickensided grain filled clay filled The fractures, which had a fracture filling and a clear colour but the core was intact across the fractures, were classified as filled. Filled fractures with intact surfaces were described as closed or partly closed. In these cases in the remarks column has been written closed or partly closed, which indicates that the fracture is healed or partly healed and its permeability is poor in its natural state. The thickness of the filling was estimated with an accuracy of 0.1 mm. The recognition of fracture fillings is qualitative and visually estimated. Where the recognition of the specified mineral was not possible, the mineral was described with a common mineral group name, such as clay and sulphides, in accordance with the fracture mineral database which Kivitieto Oy and Posiva Oy have developed (Table 3-2). Abbreviations were used during the loggings. Table 3-2. The list of the mineral abbreviations. Abbreviation Mineral Abbreviation Mineral AN = analcime NA = nakrite KS = kaolinite + other HB = hydrobiotite clay minerals BT = biotite PA = palygorsgite LM = laumontite HE = hematite CC = calcite PB = galena MH = molybdenite IL = illite CU = chalcopyrite SK = pyrite MK = pyrrhotite IS = illite + other clay minerals DO = dolomite SM = smectite MO = montmorillonite KA = kaolinite EP = epidote SR = sericite MP = black pigment KI = kaolinite + illite FG = phlogopite SV = clay mineral MS = feldspar KL = chlorite GR = graphite VM = vermikulite MU = muscovite KM = K-feldspar GS = gismondite ZN = sphalerite

15 11 The fracture surface shapes and roughness are classified using modification of Barton s (Barton et al. 1974) Q-classification (Table 3-3). In addition to this, the fracture morphology and fracture alteration were also classified according to the Q-system (Grimstad & Barton 1993). Fracture roughness was described with the joint roughness number, Jr (Table 3-4) and the fracture alteration with the joint alteration number, Ja (Table 3-5). Table 3-3. The fracture surface shapes and roughness (Barton et al. 1974). Fracture shape Planar Stepped Undulated Fracture roughness Rough Smooth Slickensided Table 3-4. The concise description of joint roughness number J r (Grimstad & Barton 1993). J r Profile i) Rock wall contact ii) Rock wall contact before 10 cm shear. 4 SRO Discontinuous joint or rough and stepped 3 SSM Stepped smooth 2 SSL Stepped slickensided 3 URO Rough and undulating 2 USM Smooth and undulating 1,5 USL Slickensided and undulating 1,5 PRO Rough or irregular, planar 1 PSM Smooth, planar 0,5 PSL Slickensided, planar Note 1. Descriptions refer to small scale features and intermediate scale features, in that order. J r No rock-wall contact when sheared 1 Zone containing clay minerals thick enough to prevent rock-wall contact 1 Sandy, gravely or crushed zone thick enough to prevent rock-wall contact Note 1. Add 1 if the mean spacing of the relevant joint set is greater than Jr = 0,5 can be used for planar slickensided joints having lineation, provided the lineations are oriented for minimum strength.

16 12 Table 3-5. The concise description of joint alteration number J a (Grimstad & Barton 1993). J a Rock wall contact (no mineral filling, only coatings). 0,75 Tightly healed, hard, non-softening impermeable filling, i.e. quartz, or epidote. 1 Unaltered joint walls, surface staining only. 2 Slightly altered joint walls. Non-softening mineral coatings, sandy particles, clay-free disintegrated rock, etc. 3 Silty or sandy clay coatings, small clay fraction (non-softening). 4 Softening or low-friction clay mineral coatings, i.e. kaolinite, mica, chlorite, talc, gypsum, and graphite, etc., and small quantities of swelling clays (discontinuous coatings, 1-2 mm or less in thickness. Rock wall contact before 10 cm shear (thin mineral fillings). 4 Sandy particles, clay-free disintegrated rock, etc. 6 Strongly over-consolidated, non-softening clay mineral fillings (continuous, <5 mm in thickness). 8 Medium or low over-consolidation, softening, clay mineral filling (continuous <5 mm in thickness) Swelling-clay fillings, i.e. montmorillonite (continuous, <5 mm in thickness). Value of J a depends on percentage of swelling clay-sized particles, and access to water, etc. No rock-wall contact when sheared (thick mineral fillings) Zones or bands of disintegrated or crushed rock and clay. 5 Zones or bands of silty- or sandy-clay, small clay fraction (non-softening) Thick, continuous zones or bands of clay. During the fracture logging the surface colour was registered, the colour often caused by the dominating fracture filling mineral or minerals, e.g. chlorite (green) or kaolinite (white). Existence of minor filling minerals usually causes some variation in the colour of the fracture surface. These shades were described e.g. as reddish or greenish. Tight fractures had typically only a slightly different shade from the host rock colour. In the fracture mapping a total of 17 fractures were recorded, Appendix 3.3. There are 13 filled fractures (76.5 %), three tight fractures (17.6 %) and one filled slickensided fracture (5.9 %). Of the 13 filled fractures, two are closed fractures and one is partly closed fracture. The frequencies of fracture surface qualities and morphologies and both joint roughness and joint alteration numbers are shown as histograms in Figures 3-2, 3-3, 3-4 and 3-5. The fractures are mainly undulated by shape (Figure 3-2). Most of the fractures have rough profile (Figure 3-3) and have high joint roughness number (Figure 3-4), indicating a high friction in the fracture surface. Low joint alteration numbers (Figure 3-5) also support this conclusion. The fracture fillings are mainly calcite, pyrite and kaolinite.

17 13 Minor occurrences of chlorite and clay minerals were also recorded. A slickensided surface contained calcite and clay material. Fracture shape stepped undulated planar Figure 3-2. Histogram of fracture shape. Fracture roughness rough smooth slickensided 0 Figure 3-3. Histogram of fracture roughness.

18 14 Joint roughness number ,5 1 1, Figure 3-4. Histogram of joint roughness number. Joint alteration number , Figure 3-5. Histogram of joint alteration number.

19 15 During the drilling, total three of qualified orientation marks were made. One (2.36 m) of these marks was discarded because of contradiction in comparison with other two marks. Still, 98.3 % of the whole drill core was orientated. The base line drawn from these marks onto the drill core acted as a ground for the measurements from the sample. From the oriented drill core sections core alpha and beta angles of every fracture were measured (Figure 3-6, Appendix 3.3). Each alpha and beta value was recalculated to real dip and dip directions using drill hole orientation and hole deviation survey data. The most common fracture direction is towards northeast (025/70). There is a minor fracture direction towards northwest with steep dip (325/88). The directions have been corrected using the directional survey data of EMS instrument. Fracture orientation is shown on an equal area lower hemisphere projection in Figure 3-7. Figure 3-6. The fracture orientation measurements from orientated core. The core alpha ( ) angle measured relatively to core axis. The core beta ( ) angle measured clockwise relatively to reference line looking downward core axis in direction of drilling. Figure modified from Rocscience Inc. Borehole orientation data pairs, Dips (v ) Help.

20 16 Figure 3-7. Fracture orientation data of all the oriented fractures on an equal area lower hemisphere projection. Contours presented are 2, 4, 6, 8, 10, 12 and 14 %. 3.5 Fracture frequency and RQD Natural fracture frequency, break frequency and RQD were logged on full metre depth intervals. Break frequency is the number of core breaks within one metre interval. Drilling, core handling, core discing and natural fractures cause breaks. Fracture frequency is the number of natural fractures within one metre interval. If the break frequency is higher than the natural fracture frequency the core must have been broken during the drilling or core handling accidentally or by purpose. If the natural fracture frequency is higher than the break frequency the fractures must be cohesive enough to keep the core together. RQD gives the percentage of over 10 cm long core segments, which are separated by natural fractures, within one metre interval. The average fracture frequency of the borehole is 1.1 pcs/m and the average RQD value is 99.4 %. Fracture frequency and RQD are shown graphically in Figure 3-8 and also presented in Appendix 3.7.

21 17 Fracture frequency and RQD Fractures/metre RQD NAT FRACTURES pieces/m RQD % 0 Figure 3-8. Frequency of natural fractures and RQD along the ONK-PVA Weathering The weathering degree of the drill core was classified according to the method developed by Korhonen et al. (1974) and Gardemeister et al. (1976) and the abbreviations are presented in Table 3-6. Table 3-6. The abbreviations of the weathering degree. Abbreviation Rp0 Rp1 Rp2 Rp3 Description of weathering type unweathered slightly weathered strongly weathered completely weathered Most of the drill core is unweathered, having only slightly pinitized cordierite grains. Only the rock section between m is slightly weathered, where occur some kaolinitization and epidotization of feldspars. The weathering degree along the ONK- PVA4 is presented in Appendix 3.9.

22 Core orientation The depth of each run where the core has been orientated has been recorded. Also the start and end depths and the length of the orientated part of the sample have been marked. If the mark has been rejected, there is a comment of this in the list. Core orientation was carried out by lowering a hinged marking spike in the hole with a wire. The spike lies against the bottom of the hole and makes a mark at the bottom of the hole. In the next run the mark will be at the upper end of the core sample and the sample may be orientated utilizing the directional information of the hole. Orientation of samples was utilized in determining the direction of fractures and other linear features in the core. The aim was to orientate as much core as possible in order to measure geological features. In ONK-PVA4, three orientation operations were carried out. One (2.36 m) of these marks was rejected because of contradiction in comparison with other two marks. In total, meters (98.3 %) of orientated sample was collected. The results are shown in Appendix 3.6.

23 19 4. ROCK MECHANICS 4.1 The rock quality The rock quality is classified using Barton s Q-classification (Rock Tunneling Quality Index, Barton, 1974 and Grimstad & Barton, 1993) during the core logging. The Q- classification was used as basis for the rock mechanical logging. The core was visually divided into sections based on the Q-value, the lengths of which can vary from less than a metre to several metres. In each section the rock quality is as homogenous as possible. The roughness and alteration numbers are estimated for each fracture surface and for each section the roughness and alteration numbers are calculated (average, median and lower and higher quartiles) and the median value is used in the Q-quality calculations. The roughness and alteration numbers are listed in the fracture table, Appendix 3.3. RQD is defined as the cumulative length of core pieces longer than 10 cm in a run divided by the total length of the core run. Q-value is calculated by equation (Barton, 1974 and Grimstad & Barton, 1993): Q RQD J * J J n r a J w * SRF Some constant values have been used. All fractures, which are closed, are classified in joint alteration (J a ) as number These closed fractures are counted as well in RQD value. In calculations joint water (J w ) and stress reduction factors (SRF) are assumed to 1. Results (Q) are presented in Appendix 4.1. According to Barton s Q-classification, the rock quality in ONK-PVA4 is very good. The rock section is composed of diatexitic gneiss (87.4 %) and mica gneiss (12.6 %), which are very intact containing just a few fractures.

24 Figure 4-1. Description of RQD and joint set number J n (Grimstad & Barton 1993). 20

25 21 5. SUMMARY Finnish parliament has ratified the Decision in Principle (the final disposal facility for spent nuclear fuel at Olkiluoto, Eurajoki) in May The decision makes it possible for Posiva Oy to concentrate its site investigations for the underground final disposal facility for spent fuel at Olkiluoto in Eurajoki. Within the next few years, an underground rock characterisation facility, ONKALO, will be built at Olkiluoto. As a part of these investigations, Suomen Malmi Oy drilled a borehole ONK-PVA4 in ONKALO for long-term monitoring purposes in a place where no grouting is done. The deviation of the borehole was measured with EMS -deviation survey tool. The ONK-PVA4 drill core is composed of diatexitic gneiss (87.4 %) and mica gneiss (12.6 %). The DGN contains biotite-rich schlierens and large amounts of cordierite grains, which are pinitized with a variable degree. A section of MGN occurs between m. The DGN is irregularly and weakly or moderately banded and most of its length in the core is very intact. The leucosome proportion in DGN varies between %, most of the rock being ca. 60 %. The rock is mostly unweathered or only slightly weathered. The feldspars are slightly kaolinitized and epidotized between m. The foliation type in the predominant rock type, DGN, is banded (87.4 %). There is a section of gneissic type in MGN between m. Filled fracture is the most common type of fracture. In the fracture mapping a total of 17 fractures were recorded. There are 13 filled fractures (76.5 %), three tight fractures (17.6 %) and one filled slickensided fracture (5.9 %). Of the 13 filled fractures, two are closed fractures and one is partly closed fracture. The average fracture frequency of the borehole is 1.1 pcs/m and the average RQD value is 99.4 %. The fractures are mainly undulated by shape and rough by profile. The fracture fillings are mainly calcite, pyrite and kaolinite. According to Barton s Q-classification, the rock quality of the ONK-PVA4 is very good.

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27 23 6. REFERENCES Barton, N., Lien, R. & Lunde, J Engineering classification of rock masses for the design of tunnel support. Rock Mechanics. December Vol. 6 No. 4. Springer Verlag. Wien, New York pp. Barton, N. & Choubey, V., The shear strength of rock joints in theory and practice. Rock Mechanics 1, s Springer-Verlag. Gardemeister, R., Johansson, S., Korhonen, P., Patrikainen, P., Tuisku, T. & Vähäsarja, P Rakennusgeologisen kallioluokituksen soveltaminen. (The application of Finnish engineering geological bedrock classification, in Finnish). Espoo: Technical Recearch Centre of Finland, Geotechnical laboratory. 38 p. Research note 25. Grimstad, E. & Barton, N Updating of the Q-system for NMT. Proceedings of Sprayed Concrete, December Fagernäs. Norway ISRM Suggested Methods for Determining the Uniaxial Compressive Strength and Deformability of Rock Materials. In Rock Characterization Testing & Monitoring. Oxford, Pergamon Press. s ISRM Suggested Method for Determining Point Load Strength. International Journal Rock Mech. Min. Sci. & Geomech. Vol. 22, no 2. S Korhonen, K-H., Gardemeister, R., Jääskeläinen, H., Niini, H. & Vähäsarja, P Rakennusalan kallioluokitus. (Engineering geological bedrock classification, in Finnish). Espoo: Technical Research Centre of Finland, Geotechnical laboratory. 78 p. Research note 12. Kärki. A. & Paulamäki, S., Petrology of Olkiluoto. POSIVA Posiva Oy, Eurajoki. Mattila, J A System of Nomenclature for Rocks in Olkiluoto. Eurajoki, Finland: Posiva Oy. Posiva Working report

28 24 Milnes, A. G., Hudson, J., Wikström, L. & Aaltonen, I Foliation: Geological Background, Rock Mechanics Significance, and Preliminary Investigations at Olkiluoto. Working Report Posiva Oy, Eurajoki. Niinimäki, R Core drilling of Pilot Hole OL-PH1 at Olkiluoto in Eurajoki Eurajoki, Finland: Posiva Oy. Posiva Working report , 95 p. Pohjanperä, P., Wanne, T. & Johansson, E Point load test results from Olkiluoto area Determination of strength of intact rock from boreholes KR1-KR28 and PH1. Working Report Posiva Oy, Eurajoki. Saltikoff, B Mineraalinimisanasto. Espoo, Geological Survey of Finland. Report of Investigation N:o 11 (in Finnish). 82 pages. ISBN

29 List of core boxes, ONK-PVA4 25 Appendix 7.1 BOX M FROM M TO NUMBER m m

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31 List of lifts, ONK-PVA4 27 Appendix 7.2 LIFT NR LIFT DEPTH LENGTH REMARKS m m Start of drilling

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33 Deviation surveys, list, EMS, ONK-PVA4 29 Appendix 7.3 EMS-survey Suomen Malmi Oy P.O.Box 10 FIN ESPOO Client: Posiva Hole No: ONK-PVA4 Diameter: NQ3 Site: Olkiluoto X: Lenght: 12 Project No: Y: Azimuth: Z: Dip: Station Northing Easting Depth Dip Azimuth

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35 Petrographical description, ONK-PVA4 31 Appendix 7.4 M FROM M TO ROCK TYPE LEUCOSOME % DESCRIPTION m m DGN 60 Irregularly and moderately banded diatexitic gneiss containing ca % leucosome. Some parts are more intensively banded, especially mesosome-rich parts. The DGN contains biotite-rich schlierens and large amounts of cordierite grains, which are pinitized with variable degree. Some sillimanite in biotite-rich parts. Disseminated pyrite in some places MGN 0 Uniform and massive MGN section. Main minerals are feldspars, biotite and quartz DGN 60 Weakly and irregularly banded diatexitic gneiss containing ca % leucosome. Some pinitized cordierite in leucosome, also small amounts of apatite and garnet in places.

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37 Degree of weathering, ONK-PVA4 33 Appendix 7.5 M FROM M TO WEATHERING Remarks m m DEGREE Rp0 Some pinitized cordierite Rp1 Kaolinitization and epidotization of feldspars Rp0 Some pinitized cordierite

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39 Foliation, ONK-PVA4 35 Appendix 7.6 M FROM M TO ELEMENT DEPTH DIP DIR DIP ALPHA BETA FOLIATION FOLIATION METHOD ROCK TYPE REMARKS m m m ( ) ( ) TYPE INTENSITY BAN 2 DGN FOL BAN 2 Sample DGN FOL BAN 2 Sample DGN FOL BAN 2 Sample DGN FOL BAN 2 Sample DGN FOL BAN 2 Sample DGN GNE 1 MGN BAN 1 DGN FOL BAN 1 Sample DGN

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41 List of fractures, ONK-PVA4 37 Appendix 7.7 FRACTURE DEPTH CORE ALPHA CORE BETA CORE GAMMA CORE DIR CORE DIP COLOUR OF FRACTURE THICKNESS OF TYPE FRACTURE FRACTURE Jr Ja CLASS OF THE REMARKS NUMBER m ( ) ( ) ( ) ( ) ( ) FRACTURE SURFACE FILLING FILLING (mm) SHAPE ROUGHNESS 3 1 FRACTURED ZONE white KA 0.2 fi undulated rough ti planar rough ti undulated rough white KA, SK, CC 0.3 fi undulated rough white KA, SK 0.4 fi undulated rough light brown SK 0.5 fi undulated rough closed light brown SK 0.4 fi undulated rough closed, branched ti undulated rough light brown SK 0.1 fi planar rough light brown SK 0.1 fi planar rough light brown SK, CC 0.2 fi undulated rough light brown SK 0.3 fi undulated rough light gray CC, SK 0.3 fi planar rough light, green CC, SK, KL 0.4 fi planar rough light brown SK, CC 0.9 fi planar rough partly closed light gray CC 0.1 fi stepped rough 4 1 intersected by previous fracture gray CC, SV 0.7 fisl undulated smooth 2 3

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43 Fracture frequency and RQD, ONK-PVA4 39 Appendix 7.8 M FROM M TO ALL FRACTURES NAT FRACTURES RQD Remarks m m pieces/m pieces/m % Two of the four natural fractures are closed One of the two natural fractures is partly closed

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45 Core orientation, ONK-PVA4 41 Appendix 7.9 MARK NR MARK DEPTH M FROM M TO LENGTH REMARKS m m m mark rejected

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47 Q-classification, ONK-PVA4 43 Appendix 7.10 M FROM M TO LENGTH OF > 10 cm Number of RQD RQD Jn Jr Ja Q PRIME Q PRIME CLASS OF THE CORE Q PRIME REMARKS m m SECTION cm fractures % >10 profile median median NUMBER CLASS FRACTURED ZONE LOSS (m) URO Very Good

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