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4 Execution4.1 Percussion drilling of borehole section 0–100 min KFM06CThe percussion drilling operations included:• preparations,• mobilization, including lining up the machine and measuring the position,• drilling, measurements, and sampling during drilling,• finishing off work,• data handling,• environmental control.The four first items are treated in the present section (Section 4.1), whereas the last twoactivities, together with the corresponding items for core drilling, are presented in Sections 4.3and 4.4.4.1.1 PreparationsThe preparation stage included the contractor’s service and function control of his equipment.The machinery was obliged to be supplied with fuel, oil and grease exclusively of the typesstated in SKB MD 600.006, see Table 1-1. Finally, the equipment was cleaned in accordancewith the cleaning instruction in SKB MD 600.004, see Table 1-1, for boreholes of SKB chemicaltype.4.1.2 MobilizationMobilization onto and at the site included preparation of the drill site, transport of drillingequipment as well as of sampling pots for soil and drill cuttings, hand tools and other necessaryoutfit. Furthermore, the mobilization included cleaning of all in-the-hole equipment at level twoin accordance with SKB MD 600.004, lining up the machine and final function control.4.1.3 Drilling, measurements and sampling during drillingThe percussion drilling started with drilling through the overburden during simultaneous casingdriving and subsequent gap injection. These activities followed the principles described inSections 3.1 and 3.2. The borehole was drilled and cased with Ø i 310 mm casing to 12.00 m.During pilot drilling fractured and unstable rock occurred and the drilling was interrupted at61.20 m whereafter the entire borehole was cement filled. After setting of the cement, drillingcontinued and the borehole was extended to 100.40 m with the pilot bit.For stabilization of the entire percussion drilled part, the borehole was reamed to 248.7 mmdiameter and 100.35 m length, and a stainless steel Ø i 200 mm casing was then installed to100.12 m lenght.Before installing the casing, the borehole was cleaned from drill cuttings by a “blow out”with the compressor working at maximum capacity during 30 minutes. This also served as ahydraulic capacity test of the borehole, as the recovery of the groundwater table was registered23
after the compressor had been turned off. The results were used as a rough capacity test of thepercussion drilled part of the borehole, used on-site i.e. for preparation of the gap injection ofthe casing, see below.In order to seal water-yielding fractures in the percussion drilled section, the gap between thecasing and borehole wall was grouted using the packer technique illustrated in Figure 3-2.After grouting, the recharge of water into the borehole ceased completely.Measurements and sampling while percussion drilling (and immediately after drilling) wereperformed according to a specific measurement-/sampling programme, which was applied inassociation with the Ø 162 mm drilling sequence. The measurement-/sampling programmeperformed was in accordance with SKB MD 610.003, see Table 1-1, and included:1) Sampling of drill cuttings at every third metre. Each sample consists of three individualsamples collected one per metre. The samples were stored in a plastic bottle marked witha sample number. Ocular inspection and a preliminary description of the mineral contentwas made on-site as a basis for classification of the rock type.2) Manual measurements of the penetration rate at every 20 cm.3) Observation of the flow rate (if any) at every 20 cm. When a significant increase of theflow rate was noticed, it was measured using a graduated vessel and a stop-watch.4) Observation of the water colour at every 20 cm.5) Measurement of the electric conductivity of the groundwater at every three metres.After completion of drilling with the Ø 162 mm drill bit, deviation measurements were made.Results from the remaining measurements and observations are presented in Chapter 5.4.1.4 Finishing off workFinishing off work included measurements of the final diameter of the drill bit after reamingto Ø 248.7 mm. The borehole was secured with a lockable stainless steel flange. The drillingequipment was removed, the site cleaned and a joint inspection made by SKB and thecontractor.4.1.5 NonconformitiesNone.4.2 Core drilling of KFM06CThe core drilling operations included:• preparations,• mobilisation, including lining up the machine and measuring the position,• drilling, measurements, and sampling during drilling,• finishing off work,• data handling,• environmental control.The first four items are presented in Section 4.2, while the last two activities are referred toin Sections 4.3 and 4.4.24
Page 5 and 6: Contents1 Introduction 72 Objective
Page 7 and 8: 1 IntroductionSite investigations a
Page 9 and 10: Figure 1-2. Borehole locations at a
Page 11 and 12: 3 EquipmentTwo types of drilling ma
Page 13: 3.3 Core drilling equipment3.3.1 Th
Page 17 and 18: • Two - 22 mm diameter hoses at a
Page 19: A log-file name, a time- or depth-i
Page 23 and 24: 4) The outer support casing was rem
Page 25 and 26: However, borehole measurements in K
Page 31 and 32: 5.4.3 Registration of drilling para
Page 33 and 34: 1200Rotation Speed1000800rpm6004002
Page 35 and 36: 16010090807014012010080605040306040
Page 37 and 38: After an almost continuous increase
Page 39 and 40: The results concerning organic cons
Page 42 and 43: Elevation66997669986699967000670011
Page 44 and 45: As seen in the diagram, the maximum
Page 46 and 47: 5.4.14 Recovery measurements after
Page 48 and 49: Appendix AWell Cad-plot of the perc
Page 50 and 51: 90100100.35100.40102.080.1620.0860.
Page 53 and 54: 53054055056057058059060061062063064
Page 55 and 56: 82083084085086087088089090091092093

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