Yang, Chan-Kyu (Korea Research Institute of Ships and Ocean Engineering) | Hong, Keyyong (Korea Research Institute of Ships and Ocean Engineering) | Choi, Hark-Sun (Korea Research Institute of Ships and Ocean Engineering)
The brief description of titanium-magnetite placers in the shelf of the Far- Eastern Seas is adduced. The appraisal of world and home experience of mining marine deposits is made. A new technological scheme of titanium-magnetite sands mining excluding disturbances of the sea ground is offered.
The Far-Eastern seas shelf is rich in alluvial deposits. Titanium-magnetite iron, vanadium, gold, tin ores and other rare and precious metals are their components. The strict observance of ecological demands excluding negative influence of mining works on fauna and flora of water area is the main technological and technical and economic principal in working out of technological approach in the design of mining-marine enterprises carrying out ~ of marine deposits.
CONDITIONS OF TITANIUM-MAGNETITE SANDS OCCURENCE
Examination of geological and economic study and comparative estimation of 1 metal content in placers of the Far-Eastern and Arctic shelf zones shows that those areas were weakly explored. Metal content of the deposits was determined in the process of search works in the beach and under-water shelf slopes of the Far-Eastern seas. The most prospective titanium-magnetite deposits are situated in Kamchatka, Kuril Islands, in western shelf of the Tartar strait, in Primorskiy territory. Productivity of under-water slope along that orebearing beach area of those deposits is different. Deposits of under-water slope propagate from the shore to the depth of 50m. Thickness of deposits varies from 4 to 16m. They are covered with overburden of 2-20m thick. New large deposit of marine vanadium titanium magnetite placers in the Tartar strait is particularly prospective. It was determined in the process of magmatic formations exploration in the middle part of the Eastern Sikhote-Alin volcanic belt by officials of the Academy of Sciences.
The Norwegian continental shelf, which covers an area of more then 1 mill km3, is subdivided into 3 separate petroleum provinces • The North Sea • The Norwegian Sea including the Jan Maven Ridge • The Barents Sea including the islands of Spitsbergen The geological characteristics, petroleum potential and teleological challenges vary within these areas. Exploration for hydrocarbons offshore Norway started in the North Sea 30 years ago and moved into areas in the Norwegian Sea and the Barents Sea in 1980. New large areas were opened for exploration in deep waters (1000-2000m) in the Norwegian Sea in 1994. Exploration in these areas will start hi 1997 and industry interest is high. A total of 520 wildcat wells have been drilled and almost 200 discoveries have been made on the Norwegian continental shelf. This gives a very high success rate (40%), which is a direct consequence of efficient exploration strategies employed over time. important elements here are: * sound balance between high and low risk exploration (no discoveries made where probability of discovery is lower titan 10%) • Sequenced approach h~ tile drilling of new prospects • Liberal data exchange policies • Extensive technological and operational cooperation between oil Companies
The total recoverable discovered and discovered and undiscovered Norwegian petroleum potential amount to approximately 12.5 billion Sm3 o.e. with an upside potential of 16 billion Sm3 (fig. 2). only 15% (2 billion Sm3 o.e. ) of these resources are so far produced. Discovered resources amount to approximately 9 billion Sm3 oil equivalents, including a potential for the improved recovery of oil and gas of almost 2 billion Sm3.
A series of centrifuge model tests are carried out to study the bearing behaviour of long flexible piles subjected to horizontal impact loads. The piles are modelled along with a fine grained sand. As model piles, aluminium pipes with an external diameter of 30 mm and a length of 695 mm are used. A free-head and a fixed-head supporting system for the pile head are considered. In these tests pile displacements at its top level, at the ground level and at its tip are measured. In addition, the applied load and the bending moment distribution along the embedded pile length as well as the wave propagation within the surrounding soil are recorded. In this paper the results of one free-head and one fixed-head pile test concerning the deflection and the bending moment distribution are presented. The time history response of both systems and the bearing behaviour of the pile-soil interface are found to be absolutely different.
The design and the performance of pile foundations under extreme dynamic loadings has a major influence on the feasibility, design, cost and reliability of a construction. Foundation performance consists of the ability of a system to sustain imposed loadings and maintain deformations within tolerable limits. Large bored piles constructed for structures such as, berthing structures, harbour dolphins and bridge piers in the environs of traffic- or waterways will serve not only as a structural element for the portion projected over the ground surface but also as a foundation to the structure. Concerning such pile constructions, the loading case due to horizontal impact has to be taken into account for the determination of the bearing behaviour of the pile-soil interface (Figure 1). The current state-of-practice for the design of horizontal impact loaded piles is fundamentally empirical.