Read/Download - SKB
Read/Download - SKB
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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 <strong>SKB</strong> 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 <strong>SKB</strong> 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