Institutt for geologi og bergteknikk Hovedoppgaver

2003 Brekke, Even: Energiuttak fra borehull i fjell. (B. Brattli) Energy Extraction from Boreholes in Hard Rock.

Bye, Trine Røisland: Storing of Water in Rock Caverns in Singapore. (E. Broch)

This thesis evaluates the potential for storing of drinking water in rock caverns in Singapore, and covers every aspect concerning cavern technology, i.e. planning, design and construction. The feasibility evaluation is primarily based on investigations carried out in the Bukit Timah Granite in an earlier feasibility study, and investigations in connection with an ammunition storage facility (UAF). These studies showed that the granite is a suitable material for cavern construction, which also was concluded from the earlier studies and the construction of the UAF. A total of 14 sites have been selected based on height requirements in three different rock formations; the Bukit Timah Granite, the Gombak Norite and the Jurong Formation. Detailed investigations in the Gombak Norite have been carried out, but available literature has however shown that the formation has similar properties as the Bukit Timah Granite. As for the Jurong Formation, the rock is competent for cavern development, but the costs will be higher. The technical feasibility, including planning, layout, design and cost are based on a typical facility storage with a storage volume of 112,000 m3. Cost estimations for both underground and above ground water facility are made, concluding that construction of underground caverns is preferable, especially considering the land premium that must be taken into consideration for an above ground water tank.

Cappelen, Paul Ingvard: Tildekking av forurensede sdimenter. (K.L. Sandvik) Capping of contaminated sediments. Sedimentation and bearing capacity of dredged material.

Capping is a new method for treatment of contaminated sediments in Norway. The goal is to isolate contaminated material and hinder the spreading of heavy metals and organic pollution from the sediment to the water column. The contaminated sediment can be capped in situ or dredged and deposited at a more suitable location before capping. In Norway, where there are deep fjords with low concentration of oxygen at the seabed, the dredged sediments can be deposited and capped to greater depths. A sedimentation test was designed to investigate the degree of mixing between fine grained dredged sediments from Bjørvika in the Oslo Fjord and coarser capping material. Crushed limestone and shell sand sieved through 2 mm sieves were used for capping. The laboratory tests showed that the capping material covered the sediments with water contents up to 300-350 per cent. At higher water contents the limestone and shell sand settled partly or fully through the sediment slurry. The main trend was that the shell sand was retained at the sediment surface earlier than the limestone. The rate of consolidation increased when mainly limestone, but to some extent also the shell sand, was mixed with the contaminated sediments. This was due to interaction between clay particles in the sediment and calcium carbonate in the capping materials. The water content was higher when the capping material was added at an early stage of the consolidation process. This shows that increased consolidation rate leads to higher water content in the final product. A load test with a circular lead was developed to measure the bearing capacity and the shear strength of the soft Oslo Harbour sediments. Four tests were performed on sediments without capping, with a two centimetre cap of shell sand and with a mixture of shell sand and sediment. No particular difference was obtained in the experiments with only sediment and with the shell sand-sediment mixture. Typical shear strength values of approximately 0,05 kPa were found. Capping with two centimetre shell sand increased the shear strength dramatically. The results show that capping of sediments with coarser material increase the bearing capacity and stability of the contaminated sediments. Although the methods used in the experiments were successful, they do not reflect real fjord or harbour conditions, and further investigations are recommended to obtain better knowledge.

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Chinh, Nguyen Huu: Engineering Geological Analysis of Sesan3 Hydropower Project, Vietnam. (B. Nilsen)

The purpose of this thesis has been to carry out engineering geological analyses of the planned underground excavations for the SeSan3 Hydropower Project in Vietnam. Feasibility studies for SeSan3 have recently been carried out by the Swedish consultant SWECO in co-operation with Vietnamese consultant PECC1. The planned project includes two approximately 80 m long and diameter 7 m lined headrace tunnels, an underground power house and 2 approximately 90 m long and diameter 7 m tailrace tunnels. Main emphasis have been placed on analysing the proposed tunnel alignments and power house cavern location and orientation, the power house design and geometry and the requirement/design of support and lining. Numerical modelling based on FLAC- 3D represents a major part of the analyses. Based on the analyses, recommendations have been made concerning design and further.

Dahl, Kjetil: Vurdering av sammenhenger mellom bergartsparametere og injeksjon ved (E. Broch) bygging av T-banetunnel. Evaluation of the Correlations between Rock Mass Properties and Grouting during Tunnel Construction.

Possible correlations between rock mass properties, consumption of grouting material and obtained water tightness for the subway tunnel between Ullevål stadion and Nydalen in Oslo have been studied. This is done as a parametre study of the different factors in the Q-system and their relevans for propagation and obtained tightness for standard grouting cements and one type of micro cement with varying water/cement – ratios and grout pressure. It is concluded that neither the Q-value itself nor any of the included factors can give a reasonably precise prognosis for the grout take. The RQD seems to be the one single factor that gives the best correlation.

Gjeldokk, Tore: Bly i overflatejord og elvesedimenter. (B. Brattli) Lead in Surface Soil and River Sediments.

Gjerde, Arild: Rogfast-tunnelen, ingeniørgeologisk analyse av trasé/linjeføring og (B. Nilsen) tverrsnittsutforming. The Rogfast Tunnel, Engineering Geological Analysis of Alignment and Geometry.

(in co-operation with the Public Roads Administration) For the Rogfast tunnel, a planned 24 km long subsea road tunnel under the Boknafjord in Southwest Norway, engineering geological analyses of the alignment and geometry have been carried out. If built, this tunnel, going down to a maximum depth below the sea level of approximately 360 meters, will be the longest and deepest subsea road tunnel in the world. The rock mass, consisting of Paleozoic phyllite and greenstone and Precambrian granitic gneiss, has been characterized based on available background material, site visits and laboratory testing. As part of the analyses, numerical modelling based on Phase2 has been carried out. It is concluded that the planned tunnel project is feasible with a minimum rock cover of 40-50 meters. For final design of alignment and geometry, more ground investigations are required.

88 Institutt for geologi og bergteknikk Hovedoppgaver

Godøy, Olaug: Tildekking av forurensede sedimenter, mobilitet til tungmetaller og PAH. (K.L. Sandvik) Capping of contaminated sediments, mobility of heavy metals and PAH.

Lately, environmental problems related to contaminated seabed sediments in Norwegian fjords have come to focus. Over a long period, environmental toxic spills have caused considerable hazards along the coastline in some areas, hence the sediments are very contaminated. Initiatives for preventing further spreading of pollution must be implemented. An economically effective alternative is to deposit the contaminated sediments under controlled conditions in the sea, and cover it with clean capping materials. An interaction between an anoxic sediment and an oxic capping material can cause chemical reactions leading to degradation of redox sensitive minerals (like oxides and FeSx), which can further lead to leaking of environmental toxics bound to minerals. On the other hand, a capping material can have positive effects regarding adsorption of heavy metals PAH. Leak- and oedometer tests have been performed to try quantifying leaking of redox sensitive metals, heavy metals and PAH from sediments, different capping materials, and a mix of these. The purpose of the test is to find an optimal design for the initiative due to type of capping material and thickness, even if it can not be concluded from the tests alone. The leak- and oedometer tests indicate that capping of contaminated sediments is a positive initiative in relation of leaking environmental toxics. A capping layer of only 1 cm thickness manages to keep the particles within the sediments, and only allows interstitial water to pass through. This result is positive as environmental toxics that are bound to particles do not disperse. The leaking of PAH is lower with an interaction between sediments and capping material than without. Some of the heavy metal leaking comes from the capping material itself. This specially applies immediately after capping. Nevertheless, a capping material will presumably have a positive effect regarding adsorbing the heavy metals from the sediments. Both limestone and gneiss are good alternatives as capping materials, though the total leaking from limestone is less than from gneiss.

Groth, Janne Bakke: Kjemisk nedbrytning av resirkulert tilslag. (B. Brattli) Chemical Degradation of Recycled Aggregate.

This Master of Science thesis is a part of a project aiming to evaluate chemical deterioration of recycled aggregate exposed to flowing water. The aim of the thesis is to do the necessary preparations to investigate the mechanical properties of recycled aggregate due to chemical deterioration. Accordingly, national and international literature on this subject is being studied. The deterioration process is explained, and the most important effects of chemical deterioration are described. Further, the recycled aggregate is documented by Norwegian and European Standard tests. The results of the tests show that the recycled aggregate satisfy the demands set by “Kontrollrådet for betongprodukter”, but the recycled aggregate consists of smaller particles than the demand for instance in Norwegian Standard NS 3420 H. To investigate the mechanical properties of the recycled aggregate it is necessary to build a full-scale experiment, but further testing in advance is demanded in order to clarify unknown factors, such as speed of reaction. The results of these tests will provide useful information about replacement of water, acid consumption and temperature dependence. The full-scale experiment is an accelerated laboratory experiment, and the effects of the accelerated exposure are estimated. The main principal for the full-scale experiment is that the recycled aggregate is being put in columns and exposed to flowing water of different qualities. The project will last for approximately 2 years. There will be taken water samples of the solution that has run through the recycled aggregate. The water samples will show the leaching from the recycled aggregate, but they will not describe the mechanical properties of the recycled aggregate. The water samples, however, will indicate the deterioration of the recycled aggregate. There will also be performed tests to document the properties of the recycled aggregate, as mechanical strength, density, water absorption and portion cement paste. These tests will show how the recycled aggregate reacts after being exposed to water. The tests are performed every 6. month, by removing one of the columns. The full-scale is designed and built during the work with the Master of Science thesis. There is also proposed a plan for sample procedures and routines for the running of the full-scale experiment.

89 Institutt for geologi og bergteknikk Hovedoppgaver

Gudmundsson, Hlynur: Analyse av utført injeksjon i Skaugumtunnelen. (B. Nilsen) Analysis of performed injectiont in the Skaugum tunnel. (in co-operation with Mika AS)

For the 104 m2/3.6 km long Skaugum railway tunnel, presently under excavation between Sandvika and Asker near Oslo, engineering geological aspects of grouting have been analysed. The extent of grouting in the tunnel has been mapped and described, and as-built results have been compared with pre-construction prognoses. Main emphasis has been placed on discussing the extent and effect of grouting versus the engineering geological conditions. Correlations between grouting results and classification parameters such as RQD and Q have also been discussed, and the usefulness of measurement while drilling (MWD) has been evaluated. Due to the very strict leakage criteria (maximum permissible inflow 4-16 l / min x 100 m), systematic grouting has been performed in the entire tunnel. It is concluded that the grouting has been mainly successful. To a great extent, this is believed to be result of the fact that grouting has been highly prioritized.

Hagen, Kjersti Fuglseth: Analyse av utført tettings-injeksjon i Lunner tunnelen. (B. Nilsen) Analysis of grouting carried out at the Lunner tunnel. (in co-operation with the Public Roads Administration)

For the 3.8 km long Lunner road tunnel, excavated as part of new Rv. 35 in Oppland (Southeastern Norway), and completed in October 2002, the effect of grouting has been analysed. Particular emphasis has been placed on discussing correlations between engineering geological conditions and extent /effect of grouting, the significance of grouting technique on grouting result, and the potential correlation between inflow in probe drillholes and the grout requirement. The extent of grouting carried out it the tunnel turned out to be considerably higher than originally estimated. It is concluded that to a great extent this is believed to be due to the fact that the joints in the rock mass were more open than expected. Finally, a comparison has been made between the grout requirement in the Lunner tunnel and the nearby Hagan road tunnel, which was excavated with a considerable smaller rock cover than the Lunner tunnel.

Haltbaakk, Jorunn: Organiske miljøgifter (musk og legemidler) i sigevann fra kommunale fyllinger (K.L. Sandvik) - adsorpsjon og nedbrytning i sandig akvifer under ulike redoksforhold. Organic compounds (musks and pharmaceuticals) in leachate from a municipal landfill – adsorption and degradation in a sandy aquifer under different redox conditions.

This thesis is a part of Jordforsks ongoing Strategical Institute Programme (SIP): “Binding and mobilisation of organic pollutants in soil and sediments; the importance for remediation processes”. The main purpose for this programme is to increase the knowledge around organic pollutants and how to reduce the negative effects different compounds has on the environment. These compounds can cause damage to human beings and the environment. One of the purposes of this programme is to study emission of organic from municipal landfills. The aim of this study was to investigate degradation and adsorption of a few organic pollutants from municipal landfills. To investigate these pollutants in a way where the results would also be valid in the field, and particularly in sandy aquifer, pilot model was developed. The model consisted of eight columns of stainless steel. The columns were connected to a reservoir of contaminated leachate which was spiked with the pharmaceutical Ipuprofen and the polycyclic musk compounds Tonalide ® and Galaxolide ®. These particular compounds were used as they have been given increased attention recent years. Research show that they are potentially hazardous and have a negative effect on the environment, the pollution being caused by sources such as leachates and disposal of drugs in waste landfills. The laboratory columns contained aquifer materials from a glacifluvial deposit nearby the actual landfill where the leachate was collected and is of same quality as the sandy aquifer beneath the landfill. A microbial inoculum was added to all columns to obtain similar hydraulic conditions. After some days 4 of the 8 columns were sterilized by y-radiation to obtain different conditions in the columns. The sterile columns were used to investigate adsorption of the added compounds while the non-sterile columns were used to investigate

90 Institutt for geologi og bergteknikk Hovedoppgaver

degradation. The columns were operated under upflow conditions (flow rate 0,87 ml/min) for 18 days. 200 litres anaerobic conditions in a nitrogen-tent and send to analysis of different parameters. In addition to degradation 2+/3+ 2- + and adsorption of the organic compounds focus was set on concentration of Fe , SO4 and NH4 in the columns. pH, conductivity and redox conditions was monitored. Potassium bromide was used as a tracer. The results are varying, but there are significant differences between the sterile and the non-sterile columns. Microorganisms occur naturally in leachate, and it can be concluded that both adsorption and degradation occurs in a contaminant plume even in a sandy aquifer. The retardation of a sandy aquifer is normally low, and the results show different rates in leaching for the sterile and non-sterile. The degradation of the organic compounds is to a large extent caused by microbial processes. It can be concluded that the results from this pilot model are valid in the field. Adsorption and particularly microbial degradation will occur in a sandy aquifer.

Hammer, Erik: En 3D seismisk undersøkelse av den sen Pliocene til Pleistocene prograderende (S.O. Johnsen) kilen utenfor Lofoten. A 3D-seismic stydy of the Late Pliocene to Pleistocene prograding wedge off Lofoten.

The study is mainly based on interpretation of 3D seismic data from the Røstbanken area, North-Norway. The main aim has been to interpret surface morphology and seismic stratigraphy in order to elucidate the Late Pliocene to Pleistocene evolution in this area. Eleven horizons were identified within the Pliocene – Pleistocene section. Hey display various surface features including, icebrtg plough marks, lineations, mega-scale glacial lineations, pock marks, recessional moraines, channels and glaciotectonic depressions. Several bright spots have also been identified, indicating the presence of gas in some areas. The horizons include the sea floor reflection in addition to ten buried horizons (A-J). The buried horizons represent upper bounding surfaces of Units (aA-jJ) indicating a westward progradation direction for Units aA and bB, and a shift to a general south-westward direction for the shallower Units cC to jJ are interpreted to have been deposited during advances of a local ice cap covering the Lofoten area. This imlies that the Lofoten area was an important source area during deposition of Units cC to jJ. The southernmost part of the study area was heavily influenced by the Trænadjupet Ice Stream during the last glacial maximum as indicated by the presence of mega-scale glacial lineations in this area. Onset of the final deglaciation occurred around 15-14 14C ka BP and three larger ice sheet re-advances are recognized during the general retreat of the ice front.

Haug, Tove Anette: Prøvepumping av løsmassebrønner for vurdering av grunnvannsuttak til (B. Brattli) smoltanlegg ved Røssåa. Terstpumping of wells in Glacial Deposits with Evaluation of Groundwater Extraction for a Fish Farm by the Stream Røssåa.

Two groundwater wells have been established by the stream Røssåa in a glaciofluvial fan that is mainly composed by sand and gravel. The wells will, together with water from Røssåa, cover the need of water for a fish farm owned by Statkraft. The desired maximum yield is set to 0,075 m3/s. Three pumping tests were conducted. One step-test in each well and in addition to this, well A was pumped with a constant yield for seven days. There were also performed size analyses of the formation samples.

The drawdown is influenced by the sloping water table with a gradient around 0,04, the partial penetration and the upward movement of the groundwater in the lower part of the fan. The coefficient of transmissivity, T1, for the step-tests, almost equals the result from the grain size analysis. T1 is probably reflecting the hydraulic properties of the soil that surrounds the wells. After a couple of hours of pumping well A, the drawdown curve changed path. It looked like the water table had met a negative boundary. The probable cause of this is when a well is surrounded by a sloping water table the cone of depression will not be the symmetrical. So when the well is pumped over a longer period, the area, which water is converging towards the well, will decrease. The coefficient of transmissivity, T2, which was calculated from the last part of the curve, will not be the correct one, but it will be used as an apparent transmissivity, which includes the hydrogeologic conditions of the aquifer when it is pumped over a long period of time.

91 Institutt for geologi og bergteknikk Hovedoppgaver

The capacities of the wells are high enough to cover the requirement of fish farm. By examining the well performance of each well, the drawdown that occurred under the pumping tests and the theoretical drawdown during maximum withdrawal, there seems to be two alternatives to the distribution of the extraction between the wells: 30% from well A and 70% from well B or just use well B until the requirement exceeds the capacity of well B, and then start pumping well A.

One water sample from each well that was taken during the pumping tests has. These samples have been analyzed for common cations and anions. Some samples taken in 2002 have also been analyzed. The groundwater is suitable both as drinking water and for fish farming, but the content of zinc exceeded the standard of secure health values for fish. It is uncertain if the source of the zinc is the deposit or the equipment used in the wells and under the tests. Further analyses of the water are therefore necessary.

T2 has been used to consider the effects of the ground water withdrawal. Neither settlement of the soil nor saltwater interference should be a problem, but the water supplies for the locals will decrease. It is difficult to determine whether the supply will go dry or just decrease.

By using the measured drawdown and calculations using Theis, Copper & Jacob and Neumans method, some of the assumptions are not fulfilled. As a consequence of not following the assumptions, the results from the calculations are just approximate. To achieve a result that is more accurate, it is necessary to perform pumping tests over a longer period of time. Then it is possible to get knowledge about variations over a year. With proper software, which can take into account all restrictions in the deposit, it is also possible to make better calculations.

Hopland, Knut Martin: Metodeutvikling for talkoppredning ved magnetseparasjon. (K.L. Sandvik) Development of Processes for Talc Benefication.

This report deals with 6 different local samples from a resource of talcrich steatite located in the northern part of Norway. These steatites contain approximately 3 – 5% oxides, among these magnetite is in majority. This mineral is not wanted when it comes to benefication of talc products, and the report touches the problems concerning the removing of this mineral. The investigations performed include crushing, sieving and magnetic separation using permroll separators. The focus on the performance of the separators and the possibilities of regulating parameters are also a main part of the report, as well as a thorough measurement of the magnetic induction. Results show that the 6 samples have many equalities, but also differences that lead to a variation in benefication. Complete results of benefication for all samples and their different fractions, together with a microscopy report from NGU, where the mineralogy is neatly presented are also included. Under influence of large magnetic induction, the benefication decreases, and the ideal induction for these samples proved to be in the amount of 0,426 tesla. Mass balance through the whole benefication process shows that the amount of fine material should be limited, cause the loss of these small size particles is relatively big for parts of the process. This should also be considered if a full scale production is to be launched. The quality of the products from the permroll separation turned out to be lower than 0,1 weight percent magnetite for the optimal parameters.

Humstad, Tore: Geotechnical evaluation of possible road tunnel project in Nuuk, West (E. Broch) Greenland.

The geology in the area relevant for a possible southwards extension of Nuuk, in West Greenland, has been investigated with respect to tunnelling. The main focus was given to the prospective Siorarsiorfik tunnel. This tunnel will be excavated through the tonalitic and granodioritic Nuuk gneisses, which are observed to have very high compressive strength of 130 – 170 MPa, medium drillability, and sound velocities of 5100 m/s. Observed Q values of 4.5 - 48 in the actual area, suggest rock mass with fair to very good sufficiency for tunnelling. Three

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alignments for the Siorarsiorfik tunnel are suggested at lengths varying from 600 to 1100 m. The constructional costs of these are estimated to be DKK 30 – 40 millions, that is DKK 34000 – 46000 per meter tunnel. Two different profiles are suggested. One of them includes extra space for a biking and walking path. The jointing in the investigated rock mss strongly depends on the NNE-SSW foliation of the rock. The strike of a major joint direction is parallel to this foliation. Due to folding of the rock mass, these joint planes dip at various angles and directions. A WNW-ESE joint direction is also prominent. However, the jointing is in general limited, as they divide the rock mass into 1 - 10 m3 blocks. Montmorillonite were found in the Nuussuaq tunnel, and is also believed to exist elsewhere in the area. There exist few major weakness zones in the area. Some scattered Quaternary deposits exist. None of these are believed to contain permafrost, despite the high air freezing indices. Locations for some entrances appropriate for subsea tunnels, are also found. The jointing was measured and, the rock quality of these is good to very good, according to the Q system. A seismic reflection line at the outlet of the Ameralik fjord, suggest the presence of a major lodgement moraine at the eastern side of the fjord threshold, and a terminal moraine at the western side. The thickness of these extends to approximately 50 m. Overlying clay deposits are probably less extensive. The depth of the bedrock table of the threshold, is believed smallest at the easternmost of the strait 110 – 130 m below sea level.

Huque, Asma: Sequence Stratigraphy of a Part of the Bengal Basin with Some Implications (S. Lippard) for the Hydrocarbon Potentiality.

A sequence stratigraphic analysis of a part of the Bengal Basin is made on two regional seismic sections collected from BOGMC. Four megasequences are recognized related to large scale basin development. Seventeen sequences are defined by unconformities. Six representative seismic facies are identified and used for depositional environment interpretation. Lateral facies change with the relative position and genetic systems tracts of the sequences and parasequence sets. They also vary with the presence or absence of parasequence sets within the same sequence. A relative sea-level curve prepared in this study shows general regression of sea-level in the Cenozoic which is similar with the published ‘global sea-level curve’. The present day Bengal Deep-sea Fan is a detached fan system from the prograding on shelf delta system. Paleochannels through the mid-shelf and near the slope indicate that they could have been the tributaries of ‘the Swatch of No Ground’ in the past. Change of shelf edge delta setting in to a low angle siliciclastic ramp setting occurred in the Oligocene-Miocene time with relation to the uplift of the Himalaya. Before the Himalayan orogeny the sediment source area was the Indian craton, after the Oligocene numerous rivers from the rising mountain contributed sediments in the Bengal Basin. The present day shelf break at about 250 km away from the shoreline could have been formed between late Miocene to early Quaternary. Potential stratigraphic traps are the topsets of lowstand deltas, offlap break of highstand deltas, lowstand wedges, channel-fill sands and the basin floor fans.

93 Institutt for geologi og bergteknikk Hovedoppgaver

Ingimarsson, Atli Karl: Ingeniørgeologisk prognose for Nordoyatunnilin på Færøyene. (E. Broch) Geotechnical Engineering Prognosis for Nordoyatunnilin in the Faeroe Islands

The rough topography of the Faeroe Islands is probably the main reason for the relative high rate of hard rock tunnel excavation in these islands for the last forty years. The geology of the islands is dominated by extrusive basalt rocks, which are 50 - 55 million years old, constituting a remarkably regular deposition with a moderate number of recorded tectonic events. The first subsea tunnel on the islands, Vágatunnilin, was excavated during 2000 - 2002, and another one, the 6.2 km Nordoyatunnilin, is currently being planned. A geotechnical engineering prognosis is made for Nordoyatunnilin, based on the experience from earlier tunnelling in the Faeroe Islands and similar rocks in Iceland. Field observations in numerous tunnels in the Faeroe Islands indicate, in general, a good rock quality for tunnelling in that type of rock mass, and necessary rock support is minimal. As a subsea tunnel in corresponding competent rock mass of compound lava flows, Vágatunnilin is providing the most important experience for this prognosis. The engineering geological preinvestigations for Vágatunnilin, and the resulting prognosis, are evaluated and compared to the later performed safety installations in the tunnel. The Q system, which is used for rock mass classification and design of the rock support, is assumed to be not fully suitable for the basalts. Therefore, it is only used to make instructive guidelines for an active design of necessary rock supports in Nordoyatunnilin. During the excavation, the decisions about the rock support will have to be based on the local geology, for each location in the tunnel. These decisions will further have to be based on an earlier experience. So are the predicted amounts of rock support for the tunnel as well, with the results from the engineering geological preliminary investigations taken into account. The tunnel will be excavated by drilling and blasting. The average progress is estimated to be 45 - 50 m/week on each working face. The tunnel project is expected to be accomplished with geotechnical project class 3 according to the Norwegian Standard NS 3480. The rock support is expected to consist of only scaling, bolts and shotcrete, with an average extent of respectively 12 m2, 3.2 bolts and 0.7 m3 per meter tunnel. Ahead of the face, probe drilling shall be used to expose possible weak rocks and water leaking zones. Only small and sporadic leakage is expected to occur in most of the tunnel, but that will not eliminate requirements for pregrouting. Based on demands for a maximum water leakage into the tunnel to be 300 l/min/km, the applied grouting mass is in average calculated to be 170 kg per meter tunnel. The grouting mass will mostly consist of rapid cement, but micro-cements should probably be used also. About 70 000 m2 of the tunnel surface is expected to be covered with mats of fireproof PE-lining for water sealing.

Jacobsen, Kine: Skråningsstabilitet og nedbørsutløste jordras langs Dovrebanen, Region Nord. (K. Rokoengen) Slope stability and precipitation induced landslides along the railways of Dovrebanen.

The purpose of Jernbaneverket’s (The Norwegian National Rail Administration) emergency plan is to prevent damages and accidents on trains caused by landslides during heavy rainfall. Landslides are often initiated during heavy rainfall and/or snowmelt. Data from recorded landslides along the railways and precipitation data from the Norwegian Meteorological Institute (DNMI) have been investigated with the intention of finding associations between precipitation and landslides and to evaluate variations in Norway. The data show partial associations, but no precise correlation can be identified from the available data. Studies of precipitation that have not resulted in landslides seem to support the assumption that a higher relative precipitation is required to get risk of landslide in areas with a low annual rainfall. In areas where the average annual rainfall is less than 600 mm, the threshold value might be increased beyond the 8% of the current emergency plan. The data further indicates that the threshold value may be increased to between 10 and 12% in areas with less than a 400 mm average annual rainfall. Draining and the use of vegetation are both alternative initiatives to the emergency plan. Draining reduces the risk of landslides by directing the surface water to trenches. Vegetation contributes to a reduction in erosion on slopes and reduces the groundwater level and pore pressure. A selection of vegetation with a variety of root systems is the most efficient way to attain an optimal binding effect within the soil. Alder, poplar, oak and elm are species that are recommended along the most vulnerable parts of the Dovrebanen railway.

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Johnsen, Iselin: Kvernede bildeke som gjenbruksmateriale i støyvoller. (T. Myran) Shedded tyres as recovered material in sound barriers.

Knudsmoen, Hanne: Analyse av nytteverdien av ingeniørgeologiske undersøkelser for (B. Nilsen) Jong-Asker-tunnelene. Analysis of the usefulness of engineering geological investigations for the Jong-Asker tunnels. (in co-operation with the National Rail Administration)

For the 104 m2 and 3.6/2.7 km long Jong-Asker railway tunnels, presently under excavation just West of Oslo, the usefulness of engineering geological investigations has been analysed. The pre-construction investigations for this tunnel project have been extensive, and during excavation, thorough mapping is carried out by engineering geologists. The correlations between investigation results and as-built geological conditions are discussed, as well as the practical use of pre-investigations results and the value of supplementary investigation during excavation. Due to the very strict leakage criteria of these tunnels (maximum permissible inflow 4-16 l / min x 100 m), particular emphasis in this thesis has been placed on investigations for prognosticating water inflow. It is concluded that the prognoses based on pre-investigations have correlated mainly quite well with the actual conditions.

Kvalheim, Endre/ Mork, Håkon: Brytningsmetode og økonomiske beregninger for Engebøfjellet. (A. Myrvang/K. Nielsen) Mining plans and costs connected to the eclogite deposit Engebøfjellet.

Lillebø, Trym Eirik: Miljøpåvirkninger og kostnader ved boring på Snøhvitfeltet. (K.L. Sandvik) Cost and Environmental Impact of Drilling at the Snøhvit Field.

Myhr, Kent Are: Støv i arbeidsmiljø og ytre miljø i Svea. (T. Myran) Dust in Working Atmosphere Environment in Svea.

Odong, Robert: Bujagali Hydroelectric Power Project in Uganda - A Case for Tunnelling (E. Broch) Option.

The thesis is aimed at analysing the Bujagali hydroelectric project on the river Nile by pulling it back to prefeasibility level. Four tunnels each 175 m2, measuring 6 km long are proposed as the alternative arrangement to offset the related impacts. Four equal size large Kaplan turbines of gross capacity of 266 MW are housed in shallow seated powerhouse cavern sited just below the intake of gross head 26.1 m at mean flow of 1200 m3/s giving a maximum head loss of 1.3 m. The maximum discharge in each turbine is 300 m3/s, leaving adequate remedial flow over the 10 m high concrete weir with only 75 m of crest length that also acts as a broad crested spillway for 10,000 yr flood of 4500 m3/s. Since the operation optimization is beyond the scope of this thesis, the total energy production per year is assumed to be in excess of 1500 GWh. On a very conservative basis, the civil cost is found to be USD 130 million which is 24% of the USD 550 million proposed by the private developer. The cavern/tunnels are designed based on the Norwegian tunnelling practice which emphasizes the importance of rock stress, weakness zones, water permeability and joint structures as factors to predict stability problems in the underground structures. Bieniawski’s RMR method of quantitative classification was ued as an empirical tool for estimating the rock support requirement in the cavern and tunnels. A fundamental assumption based on extrapolation is made upon the known set of drillholes to predict the geological conditions in the vicinity. For the little rock cover, existence of even moderate horizontal stress would greatly improve the technical feasibility of the project. Recommendation is made for further core drilling along the suggested tunnel and cavern alignment with the aim of establishing precise rock cover and rock stress sizes and directions.

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Ringdal, Anne-Christin K: En integrert rapport på kanalsystemer (S.O. Johnsen) An integrated report on channel systems

During last decades more and more attention has been brought to channel systems as their potential as reservoirs has become evident. The Ainsa area is probably one of the most studied outcrops in Europe and thus many opinions of the area has formed through time. It has been studied for decades by some of the worlds most dedicated sedimentologists with channels and channel related features as their field of interest. On the other hand, in the area of Block 25 offshore Angola the explorations have just started. In this study focus has been placed on the Quarry outcrop just south of the town of Ainsa located in the South- Eastern Pyrenees and on a channel system situated in the North-Eastern corner of Block 25, offshore Angola. The two channel systems that have been investigated are very different in size, but the geologic setting of the areas in which the systems are located have some similarities. The study of the channel systems is based on data gathered through field work and seismic data interpretation.

Raaness, Agnes M.: Mineralbalansen i prosessanlegget til North Cape Minerals på Stjernøy. (T. Malvik) The Mineral balance at the Processing Plant of North Cape Minerals at Stjernøy.

Sharma, Bishnu Prasad: Squeezing Assessment for the Melamchi Water Supply Tunnel. (E. Broch)

The proposed Melamchi Water Supply Project (MWSP) in Nepal includes a 26.3 km long water supply tunnel in metamorphic rocks, mainly migmatites, gneisses, quartzites and schists. The rocks in the Himalayas are generally weak, highly jointed, faulted, folded and tectonically disturbed. The overburden in the tunnel varies from about 75 m to about 1185 m. The main question for this thesis is an assessment for predicting squeezing conditions in Melamchi tunnel. The magnitude of tunnel convergence (% strain), and the extent of the yielding zone around the tunnel are estimated by using close form solution and Hoek-Marinos (2000) method. Both methods are developed for circular tunnel in hydrostatic stress conditions (i.e. stress ratio, k=1). However, Hoek-Marinos approach is applied for different in-situ stress conditions. Since the stress conditions are not known, the percentage strain and the plastic zone radius are calculated for different values of k for instance 1.25, 1.5, 2 etc. A brief discussion about estimating the rock mass properties is done. For the analysis, the rock mass properties are estimated by using software ‘RocLab’. The degree of squeezing is estimated for various sections in the tunnel. Empirical approach is also used to identify the squeezing conditions and a stability factor approach is used to define the degree of squeezing. Later, the sections showing the highest % strains and the yielding zone are brought into numerical modelling for further analysis. Phase2 is chosen as an appropriate numerical code for the problem. The models are run for different scenarios with varying input parameters to see the effect on principal stresses, strength factors and deformations for unsupported tunnel. The parametric study involves the different values of k, GSI, residual m and s parameters and dilation angles. One of the models is run by adding rock supports and the results are observed and compared with the results from unsupported conditions. The results from all methods including Phase2 are summarised and compared. It is found that the results from Hoek-Marinos method are very close to the Phase2 results. Finally, a brief discussion on monitoring methods is given, in conjunction with a short description of a case study. Some conclusions and the recommendations are made based on this study.

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Solberg, Inger-Lise: Geologisk utvikling og stabilitet langs Mortenelva i Målselvdalen, Troms. (K. Rokoengen) Geological development and stability along the Mortenelva river in the Målselv valley, Troms.

The Målselv valley lies 30 – 60 km proximal to the Younger Dryas ice marginal deposits in Bakkejord (Outer Malangen). During the deglaciation large volumes of sediment were deposited in the Målselv valley. Glaciomarine and glaciofluvial deposits represent the largest input, but large amounts of fluvial and marine sediments are also recorded. Fluvial erosion and landslides have formed the terrain along the Målselv river. Many of the landslides are quick-clay landslides. Three old landslides occurring in the central part of the Målselv valley have been dated to the period 2 – 5 ka BP. Mortenelva is a tributary to the Målselv river. Mortenelva meanders in the border area between a sand terrace in the east deposited during falling sea level, and an area of clay on the western side of the valley. Datings, sediment logging, drillings and investigations with GPR provide an indication as to how the sediments were deposited in the area. In 2000 there was a small landslide in the Mortenelva river. In the following year there was a larger landslide exactly in the same place. Stability calculations show that the area was not safe even before the initial landslide in 2000. What triggered the landslides can be a combination of different factors, but the most important factor was probably erosion by the river. In addition to these two landslides, three others have been reported during the last few years. This particular area is therefore the most active landslide area in the Målselv valley. NVE has constructed 10 protection installations against erosion along the Målselv river, but none has been built along the Mortenelva river. The risk for new landslides along Mortenelva is probably so great that it is recommended not to carry out any construction work near the river.

Stensland, Kjersti: Laboratoriestudium av kulemøllemetoden. (B. Brattli) A Laboratory Evaluation of the Ball Mill Method.

Unsgård, Guro: Radioaktivitet fra pukk brukt som bygningsmateriale. (T. Myran) Radioactivity from aggregate used as building materials.

Radon is a radioactive gas that can cause lung cancer at high concentrations. The levels of radon in Norwegian, Swedish and Finnish dwellings are higher than average, much due to the geological conditions in these Nordic countries. Alum shale, granite, and granite gneiss are rocks that contain high levels of naturally radioactive isotopes. These are all rocks found in great quantities in the Norwegian bedrock, and have a widespread use as aggregates. Radioactivity from aggregates used as building materials are given much attention because of an increasing awareness of the health hazard caused by radon. The opinions differ on what will be the best way of reducing this hazard. Some countries have introduced regulations controlling the content of radionuclides in building materials, which are too strict for Norwegian aggregates to pass. Other take a different approach, focusing on the construction of new dwellings rather than the contents of the building materials. Inexpensive preventive measures can be taken that are likely to reduce the indoor concentration of radon to an acceptable level. A procedure for documenting the radioactive content in aggregates is needed, in order to face the increasing requirements. This procedure would have to be able to separate the radiation from the radionuclides uranium, thorium and potassium. Analyzing samples of aggregate in a laboratory is one way of determining radioactive content. Another and better way would be to perform measurements in the field. This would capture local variations that are bound to occur, as both uranium and thorium are present only in very small amounts in the natural environment and are subject to irregular distribution.

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2004 Azad, Md Abdus Samad: Seismic and sequence stratigraphic correlation of Upper Tertiary sediments (M.B.E. Mørk) in mid-eastern Bangladesh, and petrography and diagenesis of reservoir Sandstones of the Salda Nadi gas field.

Main content: Seismic, wireline log and core data of the mid-eastern part of Bangladesh have been analysed to interpret the depositional environment of the Upper Tertiary sediments using a sequence stratigraphic approach. Sandstone samples from the Salda Nadi well 1 and 2 were studied by optical microscopy and supplementary methods to discuss petrography, provenance, diagenesis and reservoir quality. The composite seismic section and vertical litholog profiles reveal three major sequences that can be broadly correlated with the conventional lithostrati- graphic successions of Bangladesh; the Bhubon Formation, Boka Bil Formation and the Tipam Group.

Brandsegg, Kristian H.: Favorabilitetsstudie for olje- og gassfunn I Norskehavet. (R. Sinding-Larsen) Assessment of Favourability for Oil and Gas Discoveries in the Plays of the Norwegian Sea, Offshore Norway.

The objective of a petroleum exploration program is to define areas favourable for the discovery of commercial quantities of hydrocarbons. Mapping favourability for oil and gas discoveries by integrating diverse geoscience datasets has been attempted in this thesis by the use of systematic weighting of geologic factors. Two recently published methodologies with additional improvements have been used in the Norwegian Sea to quantify the favourability for the existence of new oil and gas fields. The methodology for delineating favourable areas is based upon a cell-by-cell basis where GIS is used to express different geologic factors as present or absent. Later the cells are weighted and probabilistically combined to form favourability maps. Discriminant analysis was introduced to separate dry cells from potential hydrocarbon bearing cells. Geologic variables are used to compute the favourability within a cell and statistical Krieging method is used to estimate a potential closure area. Regression of the existing discovery history in the Norwegian Sea is used to estimate reserves corresponding to this closure area. This study from the Norwegian Sea involves extensive use of GIS and geostatistics to compute influence zones that relate faults and structural boundaries to producible quantities of hydrocarbons. The petroleum data are organized in descriptive models and analyzed against the existing discoveries in order to evaluate the remaining potential of oil and gas in target areas. The study shows that statistical distributions based on geologic features can be used to map zones favourable for new discoveries and may help a company to allocate exploration effort to a region. The results imply that the proposed approach can outline favourable areas and is a methodology that includes the spatial nature of exploration variables. The methodology is capable of favourable mapping in both mature and immature areas with different levels of information. Even sparse information levels may indicate favourable areas if additional data from areas with a high levels of information are included. The study shows the capabilities of integrating geologic knowledge with GIS and geostatistics for fast and accurate evaluation of a study area.

Dahle, Halgeir: Analyse av skråningsstabilitet for Oppstadhornet. (B. Nilsen) Slope stability analysis for Oppstadhornet.

(in co-operation with NGU and International Centre for Geohazards) Oppstadhornet, a steep mountain on the Oterøya Island West of Molde, shows signs of partly collapse with initial sliding and formation of wide, open joints. As a following-up of earlier, detailed engineering geological mapping and testing, stability analysis of the steep Oppstadhornet slope has been carried out in this thesis work. Several alternatives for analyses have been discussed, and introductory empirical analyses have been done. Main emphasis has, however, been placed on numerical analysis based on UDEC-BB. Back calculation of the situation prior to initial sliding has been done as well as analysis of today’s stability situation. As an important part of the study, extensive parameter studies have been done. A main conclusion based on this work is that the mountain appears to be more stable today than prior to initial sliding.

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Ervik, Mari Nilsen: Observations of Ground Movements caused by EPB-tunneling in Singapore. (E. Broch)

Singapore in one of the most densely populated areas in the world. Underground development can solve a lot of problems in urban areas like this. In recent years, the government of Singapore has made comprehensive plans for underground systems. Among the projects going on today are the Circle Line, a new line in Singapore’s Mass Rapid Transit (MRT) system.

Construction in urban areas can be very complex. Ground movements are one of the biggest concerns. The Earth Pressure Balanced (EPB) shield machine is one method to excavate tunnels in soft ground. This method can provide stable excavation conditions and limit ground deformations in certain types of ground. There are various methods for predicting ground movements before tunneling, and various instruments to monitor and control the ground during and after construction.

The 1st Drive of Contract 822 of the Circle Line, Stage 2, was finished in the middle of January 2004. The ground conditions the tunnels went through were mostly Old Alluvium and Weathered Old Alluvium. The monitoring results showed no major settlements or heave at all, even under unexpected incidents. This confirmed the experience in previous tunneling in the same materials: Old Alluvium and Weathered Old Alluvium are very good ground conditions for EPB-tunneling.

Hansen, John Are: Paleogeografisk rekonstruksjon av Firkantenformasjonen (Paleosene) (S.O. Johnsen) I Reindalenområdet, Spitsbergen. Paleogeographic reconstruction of the Firkanten Formation (Paleocene) in the Reindalen area, Spitsbergen.

The Firkanten Formation was deposited in the early Paleocene in the Central Tertiary Basin of Spitsbergen, where it represents the basal formation of the Van Mijenfjorden Group. It rests unconformable above the lower Gretaceous Carolinefjellet formation and represents several episodes of delta progradation with an overall transgressive trend. Facies analysis and sequence stratigraphic correlation of six drill cores in the Reindalen area has revealed that the Firkanten here consists of at least eight sequences, bounded by subaerial unconformities or ravinement surfaces. The vertical stacking of these sequences has an overall transgressive trend and shows a gradual transition from an upper delta plain environment into a delta front (shoreface) environment with gradual eastwards onlap onto the basal unconformity. Deposition of the lowermost part of the Firkanten Formation was in this area largely controlled by the topography of the basal unconformity. During deposition of sequence 1 and 2, represented by a fluvial to upper delta plain environment in the study area, the paleodrainage direction had an approximately N-S trending lineation, following a topographic low in the westernmost part of the study area. As this topographic relief was smoothed out during the final stages of sequence 2, sedimentation was fully initiated in the area east and northeast of this low. A change in the paleodrainage direction also occurred at this stage and the deltas were after this building out towards the west-southwest form an area east-northeast of the study area. During sequence 3 there was still a topographic high, with exposure of the basal unconformity, located in the south-western most parts of the study are and this high probably separated the Svea from the Reindalen sub- basins. The topographic relief was however smoothed out during the early stages of sequence 4 and after deposition of sequence 4 the deltas were probably not longer constrained by the topography of the basal unconformity. After deposition of sequence 8 a rapid transgression occurred and the upper bounding surface of this sequence represents the boundary separating the Firkanten Formation from the prodelta/shelf facies of the Basilika Formation.

Hansen, Tom Frode: Analyse av rasutvikling og vannproblematikk i Svea Nord. (B. Brattli) Analyzing subsidence and water problems in Svea Nord.

Svea Nord is the name of one of the northernmost coalmines in the world and is owned by Store Norske Spitsbergen Grubekompani AS (SNSG). The mine is located to 78oN in the innermost part of the Van Mijenfjorden fiord in the central western part of Spitsbergen, Svalbard. Svea Nord is a longwall mine with an average annual production of 2 million tons of coal.

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Even though the mining so far has been mainly successful, water-problems are an increasing problem. Due to water inflow the summer of 2002 and 2003, the longwall machinery was not operable for weeks. A potential for a major water inflow in addition to this made it necessary to explain the water inflow in the mining area. The amount of water basically enters the mine in mining induced fracture in the overburden. In the summer of 2003 it was possible to observe large mining induced fractures at the Feiselen mountaintop, located vertically over the first mined panel. Fractures with a length of 200 – 300 m and an expected width of 1 – 2 m almost divided the mountain in two parts. To be able to explain the water inflow to the mine you have to understand the interaction between mining induced fractures of the rock mass, the source of water and its patterns of movement.

Collected and calculated data assumes a rapid development of subsidence and the dynamic subsidence constitutes a major part of the final subsidence. The rapid subsidence is mainly explained by a major fracturing of the overburden above the sides of the panel. The surface above the central parts of the panel will therefore subside rapidly. The fracturing can probably be explained by an interaction between the three factors: high rock quality, steep topography and a high stress regime with a large ratio between the maximum and the minimum horizontal stress value. The rock mass will probably fracture more violently in areas with steep topography than in more level areas.

The course of events during the water inflow the summer 2002 is according to today’s knowledge a typical example of a sudden inflow with rather large amounts of water: 1. Fracturing of the rock mass in a zone of 70 – 100 m above the seam, makes the water in the saturated rock mass migrating towards the longwall area. 2. A sudden violent fracturing along the sides of the panel penetrates a water-bearing channel in the surface and large amounts of water percolates to the fractured zone and down to the caving area. 3. A fold- and faulting zone is probably exposed to a certain form of reactivation and this cause an increased permeability in the area. From this course of events you can make the conclusion that the sudden water inflows in most cases is restricted to sudden violent fracturing, as long as there exists sufficient amount of water.

In an assumed graben zone in the northern part of the mining area there is low overburden (75 – 100 m) and there are probably occurring large amounts of water laterally or inside the covering glacier. Due to the low overburden it is possible that an estimated 70 – 100 m fractured zone reach the surface. This comes in addition to the contribution from fracturing along the sides of the panel. In the future this area will have a major potential for a major water inflow.

Helgason, Peder Eide: Fysikalsk-kjemisk drikkevannskvalitet i godkjenningspliktige grunnvanns- (B. Brattli) verk i Norge. Physio-chemical drinking water quality of groundwater works in Norway subject to certification.

In February and March 2004, water samples were collected from 351 groundwater wells distributed between 179 waterworks. The samples were analysed for 32 cations by ICP-AES, 7 anions by IC, and for pH, alkalinity, colour, turbidity and electrical conductivity.

Most of the wells were dominated by calcium and bicarbonate. 3% of the water samples were dominated by sodium and bicarbonate. These samples, which were all from bedrock aquifers, had a high pH value and are considered as mature groundwater. The high sodium content is probably the result of weathering processes. 20% of the samples were from immature groundwater dominated by sodium and chloride. These samples had a low pH value, and were from Quaternary as well as bedrock aquifers. Some of the samples were dominated by Ca- Cl2 og Ca-SO4.

The total ionic content in most samples was much lower than expected. This might be because of short groundwater residence time. The groundwater wells can also be influenced by surface water. The concentration of most anions and cations was highest in samples from bedrock aquifers. However, the concentration of nitrate, aluminium and copper was highest in samples from Quaternary aquifers.

The pH values of the water samples depended on aquifer type. Samples from Quaternary aquifers had a median value of 7.37, while samples from bedrock aquifers had a median value of 8.17. The samples from the coast of

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Western and Southern Norway had the lowest pH values. This may be due to lithological variations in soil thickness. Most parameters showed a similar pattern.

The hardness and the fluoride concentration in the water samples, seem to depend on the bedrock geology. Hard groundwater was most common in samples from the Caledonian mountain range, while the fluoride con- centrations were highest in samples from bedrock aquifers in granitic rocks.

The water samples seem to be moderately influenced by human activity. Nitrate concentrations were lower than in most European countries, but had a distinct correlation with potassium. Fertilizers on agricultural areas are therefore considered to be an important source of nitrate in the groundwater. Some samples with high concentrations of calcium and chloride, can be polluted by salts used for de-icing of roads.

35.6% of the water samples have a quality that fail to satisfy the present Norwegian drinking water regulations. The maximum concentration limit of manganese is most frequently exceeded, with 17% of the samples above the limit.

Huy, Le Quang: Engineering geological assessment of the dam site for the Quang Tri (E. Broch) multipurpose project in Viet Nam.

Quang Tri Multipurpose Project is located in the central part of Vietnam. Main objectives of the project are irrigation, power generation and flood control. The project consists of a dam and a spillway, and of headrace and tailrace tunnel and an underground powerhouse. The main dam with a maximum height of 85 m is positioned on a complex geological foundation consisting of granitic rocks and gneiss with good quality and relatively thin weathering cover on the left bank. On the right bank ancient soil strata are covered by different basalt flows with various degrees of weathering. These materials, combined with gneiss and schists underneath, make a mix of strong and weak rocks. Further from the river intensively weathered rocks developed on basalt and schists create an overburden up to 80 m thick. Three fault systems are found. An engineering geological evaluation of the dam site is carried out. Missing data are estimated, such as properties of intensively weathered rocks, joint strengths, strengths and deformations of rock masses, etc. Rock masses on the left bank and in the river bed are considered as good foundation, whereas the soil and rock masses on the right bank have various qualities, making a low quality foundation area. This leads to a proposal of a combination of a rockfill dam with central earth core, an earthfill dam and a transition between them. The rockfill dam may be located on strongly weathered rocks and the earthfill dam should on the intensively weathered rocks. Main measures to prevent leakage in the foundation are an integration of cutoff and grouting curtain. Consolidation grouting is necessary in the area of cutoff. An analysis has been done for rock slopes of the dam abutments and around inlet and outlet of diversion tunnels. Stable angles in construction case for each slope have been found. A preliminary design for diversion tunnels proves that the diversion tunnels must be positioned on the left bank. Two unlined tunnels, each with an area of 150 m2, are proposed. Support measures are predicted as mainly systematic bolts, supplemented by an optional layer of unreinforced shotcrete.

Kaldheim, Linda C.: Petrografi og diagenese av sandstein fra Lysingformasjonen, Norskehavet. (M.B.E. Mørk) Petrography and Diagenesis of Sandstone from the Lysing Formation, The Norwegian Sea.

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Kvitsand, Hanne M. L.: Grunnvannsforsyning til Turhaugen vannverk, Levanger kommune. (B. Brattli) Utredning av metoder for reduksjon av hardhet i grunnvann. Ground water supply to Turhaugen Water works, Levanger kommune. Reduction of hardness.

Asplan Viak AS has on behalf of Levanger kommune investigated the possibilities for upgrading Torhaugen waterworks in Åsen. Ground water supply was considered to be the best alternative and test well was established in a glaciofluvial deposit. Pumping from the test well has shown the aquifer’s capacity is big enough to cover the waterworks’ water requirement and that the ground water is of good quality. The concentration of calcium was however so high that any use of the water would imply disadvantages for the consumers. Possibilities for reducing the hardness are therefore evaluated, by investigating the effects of changing the dimensions of the test well and by considering methods for water softening.

The first period of test pumping was carried out by pumping from both of the well’s two infiltration filters. The dimensions of the well were then changed by installing a sealing plug underneath the upper filter to examine the effects this would have on ground water chemistry, retention time and exploitation capacity. Pumping test, water analysis and measurements of the ground water level was completed during both test periods.

The concentrations of soda and chlorine augmented during the 2. Pumping period due to larger advection caused by increased exploitation. The increase in concentration of sulphate was caused by greater infiltration of surface water during 2. Period, which in turn lead to enhanced weathering of pyrite. The alkalinity was reduced while the concentration of calcium was more or less the same. The ground water retention time was reduced and the exploitation capacity increased caused by a combination of increased exploitation and favoured ground water flow in the formation’s upper stratum. Reduction of retention time implies extension of the area of activity restrictions.

The test pumping showed that the calcium concentration was not reduced during pumping with the sealing plug. It is therefore necessary to treat the water before distribution to the consumers. Ion exchange is the most effective economical method for softening the water. For water supply to Torhaugen waterworks three ion exchange columns are needed for softening to acceptable hardness at 4 odH. The waste water’s salt content will result in an increase of the recipient’s natural salt concentration from ca. 6,7 mg/l to 6,9 mg/l.

Nesse, Elisabeth: Urban avrenning som mulig forurensningskilde fra Drammen og Lier (B. Brattli) til Drammensfjorden. Runoff from Urban Areas in Drammen and Lier as Possible Source of Contamination in the Drammensfjorden.

Ngo, Quang Huy: Central African Rift System, Origin of Development and Hydrocarbon (R. Sinding-Larsen) Potential.

Central African Rift System is often referred to as Central African Rift Subsystem (CAS). It is one of the two major parts that create the Western and Central African Rift System (WCAS) which extends 4000 kilometer from Niger to Kenya. The second part is usually called as West African Rift Subsystem (WAS). These subsystems are related genetically but separated physically. The CAS extends from Cameroon through southern Chad, Central African Republic into Sudan and part of Kenya. The most important Cretaceous-Tertiary rift basins that make up the CAS are the Bongor, Doba, Doseo, Salamat and Muglad.

Plate tectonic separation between Africa and South America has played an important part in the rift development. The gradual opening of the Central and South Atlantic oceans from around 130 Ma was responsible for two major phases of basin development in Central African Rift System, the Neocomian-early Aptian and mid Aptian-Albian episodes respectively. The CAS is considered as typical “plassive” type rift which evolved in response to the build-up of intraplate stresses. However, “active” rifting which involves magmatic activities may have a role in the process. The St. Helena hot spot may have weakened the lithosphere across the region at approximately 120 Ma.

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The Cretaceous-Tertiary rift basins of the CAS are extensional to transtensional and contain up to 7500 meters of predominantly Cretaceous continental clastics. Oil and gas discoveries have been made in most of these basins and production, in its starting stage, has already begun. Heavy to light oil and gas accumulations are situated in Lower and Upper Cretaceous fluvial to lacustrine sandstones reservoirs. The hydrocarbons are sourced from Lower Cretaceous shales and sealed by lacrustrine to flood-plain shale and mudstone, with traps in mainly faulted anticlinal closures. Structural styles vary from simple fault blocks to complex flower structures. Petroleum geology indicates that further potentially commercial volumes of hydrocarbons in these Central African Rift System basins remain to be discovered. Mean estimates of inplace and recoverable resources for the CAS using GeoX/Starter are around 3.98 and 1.51 billion barrels respectively. The Muglad basin alone accounts for more than sixty percent of these figures.

Nguyen, Tra My: A study of tunnels and underground powerhouse for the Huoi Quang (E. Broch) Hydropower Project in Vietnam.

Huoi Quang Project is located on Nam Mu River, Vietnam. Main objectives of the project are power generation and flood control. The project composes of a gravity dam, a spillway, and headrace and tailrace tunnel and a underground powerhouse. Maximum head is 150 mm discharge is 420 m3/s and installation capacity 3 x 180 MW.

Based on Norwegian approach in designing underground structures the tunnel, the pressure shaft and the powerhouse have been redesigned. The headrace and tailrace tunnels are optimized as unlined tunnels. The Q and RMR method is used to classify the rock mass and the tunnel support is designed based on this method.

Numerical models are established to evaluate virgin stress situation, stress after excavation of tunnel and to find the sound location for powerhouse. Recommendations are made in order to improve the models by taken into account some factors, which had not been involving in the created models. The factors are the water table, the excavation of the opening and the support methods.

Nilsen, Kristin Husebø: A geological investigation of the Tellnes deposit. (T. Malvik)

The Tellnes ore body is located in the southern part of Rogaland, Norway. A diamond drilling program was carried out in 2004 in the open pit mine and the area east of the pit. These two areas are divided by a crossing lineament. West of the lineament both the geology and how the ore behaves in the process are well known. East of the lineament the information is limited. This diploma thesis has compared these areas. The minerals in the eastern part of the ore body contain other minerals and has a different chemical content compared to the ore in the existing pit and in the crossing lineament.

Data from the geology and the chemical analysis of the cores from the diamond drilling are imported to the existing computer model of the Tellnes ore body. This existing model is evaluated according to how the new information corresponds to the accuracy of the existing model. The new data correspond quite well with the model in the area of the existing open pit mine and in the crossing lineament, but not so well in the area east of the lineament. In this area east of the lineament a new model was created using both old and new data of the boreholes. The new model shows that the ore body is closer to the surface compared to the old model. Furthermore, the new model shows a distinct layering of an upper layer and a deeper layer. The upper layer contains less TiO2, while the deeper layer is similar to the ore in the existing open pit mine and in the crossing lineament. This information indicates that the ore in the eastern area is younger than the western area of the Tellnes ore body.

Olsen, Morten C. Nøst: The Spreading of Heavy Metals from the Ordot Landfill to Biotic (B. Brattli) Species and Sediments in Local Rivers on Guam.

This thesis was undertaken to determine concentration of heavy metals in abiotic and biotic components in three rivers in close vicinity of the Ordot Landfill on the island of Guam in the Western Pacific Ocean. The Ordot

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Landfill is located near the village of Ordot in the central part of Guam, and has been operating as the island’s primary landfill for industrial and municipal waste since the end of World War II. There are no early records documenting the nature and quantity of hazardous wastes disposed of at the site, but it is known that the landfill has been the recipient of a variety of uncontrolled wastes, including munitions, polychlorinated biphenyl (PCB)- contaminated oils from transformers and spent industrial and commercial chemicals.

The Ordot Landfill lacks the conventional technology built in to modern day sanitary landfills, such as daily soil covers, impermeable membranes, and leachate collecting systems. As a result, several methane fires have occurred at the dump, which have required the temporary evacuation of nearby residents. Moreover, surface water idrainage and rainfall produce percolation of water through the trash prism and generates leachate streams down gradient of the landfill. The leachate is discharged into the Lonfit River, south of the landfill. Further south-east of the dump the Lonfit River merges with the Sigua River, which creates the Pago River. This river drains eastwards and emanates into the Pago Bay estuary on the eastern coast of Guam. The chemical composition of the discharged leachate and its impact on the local freshwater envisonment is largely unknown.

The Ordot Landfill has been suspected for contaminating the local environment and has received attention from the United States Environmental Protective Agency (U.S. EPA) since the beginning of the 1980s. The Guam Department of Public Works (Guam DPW) which is responsible for the operations at the Ordot dump, received orders to cease the discharge of leachate to the Lonfit Riber already in 1986, but this has not been accomplished, and the discharge has continued to contemporary times. In 2003 a lawsuit filed by the U.S. Department of Justice, on behalf of the U.S. EPA in August 2002, mandated the Government of Guam to close the landfill by the year of 2007. Little is known of the fate of the pollutants which have been released to the local surface watershed throughout the years.

Anually the freshwater rivers on Guam are also transporting large amounts of sediments from erosion and weathering processes of volcanic bedrock and soils to the shores around the southern part of the island. The impact of these sediments on the Pago Bay estuary and on the coral reef in Pago Bay is unknown. Little is also known of the levels of adsorbed heavy metals in the deposited sediments and the fate of these in the estuary.

During the period of August 2003 – March 2004 river sediment samples and biotic representatives of the freshwater fauna and flora were collected from a total of 15 sites. The locations of the sites were in the leachate streams, and in the Lonfit, the Pago and Sigua Rivers. Sediments were collected from all 15 sites, while biotic species were not represented at all locations. All sampling locations are described in detail in the thesis. The dominant biotic groups examined were fish, crustaceans, gastropods and aquatic weeds. All samples analyzed were following conventional wet oxidation procedures in hot mineral acids. Nine elements (Ag, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were analyzed by the use of flame atomic absorption spectroscopy (AAS), while the tenth element (Hg) was analyzed with flameless cold vapor AAS. The findings of the analysis have been evaluated and discussed in relation to possible sources of input. A detailed comparative analysis with findings reported by other researches of related species from elsewhere have also been executed.

In oveall, the sediment samples from the leachate streams showed increased levels of Fe, Mn, Zn and Hg compared to measured concentration in river sediments. However, when the findings in leachate and river sediments were compared to the established threshold values for the individual elements, Fe, Mn, Cr, Cu and Ni were found to be exceeding these values. Based on threshold values, most investigated river sites in the Lonfit and Pago Rivers could be described as moderately contaminated with respect to these elements. However, it was evident that the detected exceedances downstream of the landfill were strongly related to the background levels of these elements represented in the local geology and soils, and not primarily results of leachate discharge from the Ordot dump. Based on the findings from upstream and downstream rivers sediments in the Lonfit River, and the findings in the neighboring Sigua River, it could not be established that the landfill was contributing to significantly increased levels of heavy metals in the sediments of the Pago and Lonfit Rivers with respect to the ten elements investigated.

The analyzed specimens of fish and crustacerans did not exceed established food standards and guidance limits. These findings indicated that the levels of heavy metals in the investigated biotic species of fish and crustaceans are not in particular affected by the discharge of these ten metals from the Ordot Landfill, or from metals derived from the local geology and soils. The findings in gastropods indicated possible bioindicator potentials for Mn and Fe with Neritina Pulligera, and for Mn and Cu with Neritina variegata. However, these findings

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may also be a result of naturally occurring elements in the organism’s biochemistry and the actual reason for increased levels of those trace elements remains uncertain after this study. The aquatic weeds, Hydrilla verticillata, collected from one Pago River site had Fe/Mn ratios equivalent to levels which would indicate Mn- toxicity and Fe deficiency. Interesting enough, samples of Hydrilla verticillata from a further downstream Pago site had healthy Fe/Mn ratios.

Ecological and environmental observations are included in the present study, and discrepancies and uncertainties related to the research have been commented. Recommendations for future directions of continued research in the Lonfit and Pago Rivers and in Pago Bay have been suggested, and clean up alternatives related to the closure of the landfill are also presented.

Seim, Kai Inge: Minimalisering av krominnhold i endelig ilmenittkonsentrat ved (K.L. Sandvik) Titania A/S ved forbedret svakfelt magnet separasjon. Minimalisation of the chrome content of the final ilmenite concentrate by Titania A/S by improvements in low intensity magnetic separation.

The objective of this thesis is to evaluate present and future use of low intensity magnetic separation to minimize the chromium content of the ilmenite product from the Norwegian mine Titania. Ilmenite is there mined from the world largest titanium deposit in solid rock. The deposit has however, a content of 2% magnetite which hold 0,8 – 1% chrome. Removal of magnetite is therefore important.

The main goal has been to reduce the chrome in the concentrate by increasing the recovery of magnetite in the primary LIMS installation. Tests were done to pump part of the magnetite concentrate back to the primary separation stage. The hypothesis was that a higher magnetite loading on the separator would improve separation. The results were negative and showed that the content of magnetite in the non-magnetic discharge increased.

Another point was to investigate if the magnetite in the gravitational concentrate could be reduced significantly by further magnetic separation. A pilot test separator was placed after the spirals which produce this con- centrate. The results were positive and demonstrated that the magnetic content could be reduced.

As a part of a plan to improve the present flowsheet, a comparison of one Ø1200 counter-current separator with one con current was done. The result showed that the counter-current separator was equal or better than the con current.

Microscopic investigations were done on the magnetite which passed through the magnetic field in the primary circuit. Mostly locked particles of magnetite were found, but liberated particles occurred. The magnetite that was found in the gravitational concentrate was mainly liberated magnetite which was unexpected.

Shrestha, Pawan K.: Engineering geological analysis of underground structures at Middle (B. Nilsen) Marsyangdi Hydroelectric Project, Nepal.

Construction work for the Middle Marsyangdi project started in 2002 and is expected to be completed in 2006. Among the main underground excavations for the project are 3 large settling basins, each with width ~15 m, height ~ 30 m and length ~ 150 m, and a 5 km long headrace tunnel (the powerhouse is located on the surface). The bedrock in the area mainly consists of foliated quartzite, and the rock cover of the underground structures is relatively small. The purpose of this thesis has been to analyse the engineering geological aspects of the underground excavations of the project, with main emphasis on the large settling basins. Stability, cavern design and rock support requirement have be analysed with main emphasis on empirical analysis and numerical analysis based on the Phase2 FEM code.

Skjærpe, Ivar Martin: Paleocen sand distribusjon på Sørvestlandet Høyden. (S.O. Johnsen) Paleocene sand distribution on Sørvestlandet High.

The Sørvestlandet High lies up from the Central Trough in the southern part of the Norwegian sector. Wells drilled in the area show that shales predominantly comprise the Paleocene interval. This is not surprising

105 Institutt for geologi og bergteknikk Hovedoppgaver

considering that these wells are mainly drilled on pre Paleocene stratigraphic traps, mainly salt induced. As these structural highs made out the Paleocene bathymetry in the area, possible turbidite sands have eluded these areas and most probably deposited in near by rim synclines and basins.

The turbidite sand found in the Paleocene interval, in wells around the Gyda and Ula fields in the Central Trough could very well origin from the Norwegian continental shelf and not the East Shetland Platform and the Scottish Highlands as previously believed. Formation thickening up slope to the Sørvestlandet High, as well as obvious channel cuts are indications of this. It is possible, from this study, to be certain that the thickening on Sørvestlandet High is due to turbidites that are in connection with the ones found in the Central Trough. Seismic tm resolution, even on HFI reprocessed data, proved to low for convincing tracking up slope.

Secondary migration is a key issue for the Sørvestlandet High to be a prosperous area as the Mandal formation in the Upper Jurassic interval is immature here. Hydrocarbons are thought to have migrated from the kitchen area in the Central Trough. There are at least two good possibilities for the migration through the Gretaceous and into Triassic sands. The extensive faulting on the graben flanks is one possibility. However, we have strong indications of sealing in at least one location. The other suggestion is migration through micro-fractures associated with the vast numbers of salt diapirs in the area. This provides a multitude of potential pathways for the hydrocarbons.

The Depositional Models presented in the study reveals plausible distribution maps for Paleocene sands on Sørvestlandet High.

Tøndel, Tonje D.: Stratigrafi og diagenese i Lisburnegruppen, Endicott Mountains, arktisk (S.O. Johnsen) Alaska. Stratigraphy and Diagenesis of the Lisburne Group, Endicott Mountains, Arctic Alaska.

The Lisburne Group in Brooks Range, northern Alaska makes up a thick sequence (> 400 m) of laterally extensive carbonate deposits. It apparently developed along a southward passive continental margin, on a subsiding carbonate ramp. The Lisburne Group records cyclic stratigraphic successions, alternating from open marine to restricted lagoon facies. Facies stacking pattern suggests that a northward transgression onlapped terrigenous deposits of the Endicott Group.

The Wachsmuth Limestone is at least 300m thick and consists mainly of skeletal packstone and grainstone. The packstones and grainstones are poorly sorted, have a high abundance of disarticulated valves and moderate evidence of abrasion. The absence of carbonate mud indicates that most of deposition took place above wave base. The Alapah Limestone is finer-grained, consists of darker, more argillaceous mudstones and wackestones with a predominance of carbonate mud that indicates that most deposition took place below wave base.

Several stages of diagenesis occurred in the limestones. The first is a void filling fabric followed by micritic rim, followed by syntaxial cement, which is considered to be the first phase of sparry calcite cementation. The second phase is a blocky calcite cement which completely obliterates the available pore space with subequant crystals that are coarser than the first-phase cement.

Great dolomite concentrations are not common in the Lisburne Group of central Brooks Range. However, minor dolostone beds are seen. The dolomites are found both as matrix material and as replacement fabric, which result in crystalline rocks.

Westre, Kjetil: Overpalaeozoikum karbonatreservoargeologi med vekt på gzelintervallet på (M.B.E. Mørk) Finnmarksplattformen, Barentshavet. Upper Palaeozoic Carbonate reservoir geology focusing on the Gzhelian at the Finnmark Platform, Barents Sea

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