The National Major Dam Walls dataset presents the spatial locations; in point and polygon format, of all known major dam walls within Australia.

On May 3rd, and again on June 1st, the author visited the Cotter dam to investigate a reported loss of water from the fault on the northern side of the wall. This report gives an account of these visits, together with the author's observations and conclusions in relation to the reported water loss.

The geophysical survey described in this report was undertaken at the request of the Snowy Mountains Authority for the purpose of investigating possible sites for the proposed Spencer's Creek dam. The area surveyed is about two miles above the junction of Spencer's Creek with the Snowy River, about six miles east of the summit of Mt. Kosciuszko, and at an average elevation of about 5,700 feet above sea level. The specific information sought by the survey comprised the following: depth and nature of the bedrock, contours of the bedrock surface, nature of the overburden, and in particular, variations in physical properties occurring either horizontally or vertically. The seismic refraction method was used in the survey. This report gives an account of the geophysical survey and its results.

A site for a National Park Reserve is proposed at the head of the Tidbinbilla River, and a Zoological Park is planned, within the city limits, between Yarralumla Nursery and the Molonglo River. The Department of the Interior has requested geological information on these sites with special reference to supply of building stone. The geology of the proposed sites is described in this report. Possible sources of building stone in the vicinity of these sites are considered.

An examination of a small area flanking the Molonglo River at Acton was undertaken at the request of the Department of Works and Housing. The construction of the weir across the river within the area examined to raise the water level to 1825' is proposed, and the geological investigation was carried out in connection with this proposed work. Aspects of general geology and engineering geology are discussed. A geological plan and sketch sections are included.

On 29th September, 1948, the writer, assisted by K.R. Fleischman, spent one day examining the rocks of the Cotter River Valley in the neighbourhood of the dam and mapping geological features which would have a bearing on the proposed extensions. Representative rocks were collected from the quarries on the right bank of the River below the dam. The mapping was done by chain, compass and Abney level. Aspects of general geology and engineering geology are discussed in this report. Two accompanying geological plans are included.

The four field parties and the Airborne Geophysical Section continued operations in the area during the quarter ending 30th September, 1953. This report provides a summary of the geological and geophysical operations carried out during this period, and an overview of the staff and housing situation.

At the request of the Tasmanian Hydro-Electric Commission a geophysical survey was carried out along a tunnel line at Trevallyn, a suburb of Launceston, North Eastern Tasmania. The excavation of the Trevallyn tunnel is part of the Hydro-Electric Trevallyn Power Development project to utilise the water of the South Esk river for generation of electric power. The construction works are already well advanced. A dam is being built on the river at the Second Basin. Water from the catchment will be diverted through a tunnel two miles long to a power station situated at sea level on the Tamar River. A locality map is given in Plate 1. Three geophysical exploration methods, electrical, seismic and gravitational, were used to locate deeply weathered and fractured zones in the dolerite bedrock, through which the tunnel is being driven.

An investigation into the possibility of providing additional water supplies to the township of Tennant Creek was carried out by the Department of Works and Housing. A request was made to the Bureau in March, 1947, to carry out a geological examination of possible dam sites in the Tennant Creek area. A preliminary inspection of two possible sites was made on 5th June, and a detailed plane table survey of both sites was carried out on 6th and 7th July, 1947. The location, access, topography, general geology, engineering geology, and recommendations for future investigation and work are discussed in this report.

The overburden (or non-scheelite bearing rocks overlying the ore-bearing rocks) at the mine of the King Scheelite N.L. at Grassy include: 1) A layer of windblown sand ranging in thickness up to 30 feet; 2) An irregular layer of non-mineralised rocks occurring in the north-western part of the present workings; 3) Non-mineralised rocks conformably overlying the lode in the southern part of the workings; 4) Overburden dumped on the southern side of the open cut. The problem of the dumping of the overburden is involved in that of the selection of a suitable site for the treatment plant. Under the proposed scheme to increase production a new site will have to be found for the treatment plant that is to be erected.