Iron Grit Research Articles

The Gault Clay–Folkestone Beds junction in West Sussex, Southeast England

The Iron Grit, a limonitic sandstone developed at the base of the Gault between Midhurst and Washington, is suggested to be a primary deposit which accumulated in lagoonal conditions on the flanks of the newly emergent Portsdown Swell. The underlying Folkestone Beds have a coarsening-upwards profile combined with upward decrease in amplitude of cross-bedding and pass upwards into parallel laminated sands directly beneath the Iron Grit, a sequence interpreted as representing a beachface profile. The Iron Grit represents a drop in sustained depositional energy and removal from the beachface environment. SEM studies of quartz grain surface texture demonstrate an increase in impact textures upwards in the Folkestone Beds, but a decrease in the Iron Grit. Heavy mineral suites of the Folkestone Beds are characteristic for the Weald, but the suite in the Iron Grit is deficient in kyanite. The wide variety of mineral species confined to the Iron Grit illustrates protection from intrastratal solution by early cementation. The iron is suggested to have originated from weathering on the emergent land area. The Portsdown Swell uplift is related to a mid-Leymeriella tardefurcata phase of regional tectonism.

PVC melt stability relationship to impurity chemistry of carbon black

A major concern for processing Polyvinylchloride filled with enough carbon black to make an electrically conductive plastic is maintaining sufficient compound melt stability for molding. Selective removal of various heteroatoms and impurities (e.g. oxygen, sulfur and inorganic salts) from carbon black indicates that excessive concentrations of either surface oxygen or iron grit adversely affects the melt stability of polyvinylchloride.

Reversals of Natural Magnetization within the Iron Grit of Sussex

Summary Normal and reversed natural remanent magnetizations of a band of iron grit, usually less than 3 in thick and found north of the South Downs in Sussex, formed layers which slanted close to the horizontal. No significant physical or chemical difference between normal and reversed parts of the grit was detected. The nature of the evidence obtained makes it practically impossible in this case to decide between a field reversal and a self reversal theory.

NEWS OF INDUSTRY

Tunnel Cleaning Contract. We are informed that Coating Contractors Ltd. have completed a contract in Wales for the blast cleaning (Fig. 1) and coating of the steel linings and penstocks at Blaenau Ffestiniog and Cwm Rheidol hydro‐electric projects. About three miles of tunnel lining, measuring 9 ft 6 in diam, were involved. Fifty‐two tons of chilled iron grit were used to remove, by blast cleaning, 37 tons of rust and millscale, and the cleaned surface was protected with 52 tons of Adcora Pervon polyurethane pitch coating. The work was carried out for the Central Electricity Generating Board.

Waukegan Filtration and Pumping Plant

The City of Waukegan has awakened to the advantages of its location on the Great Lakes and the possibility of rapid increases in population and commercial importance. Many of its citizens have come to realize that living conditions are important factors in expansion and, of these, that a good water supply is a prime condition. To this end an up-to-date system of water supply was authorized by this city, the main portion of which, the filtration and pumping plant, is now in successful operation. The plant is situated on a peninsula at the north entrance to Waukegan Harbor. For a practical as well as artistic effect, the front faces the south, where it can be plainly seen from sea and shore. At present a 24-inch inlet main, installed several years ago, extends in an easterly direction into the lake, the outer end being about 3,000 feet from the shore in a depth of water about 25 feet. As the deep water is in a south easterly direction it was decided, on grounds of permanency and reliability, to construct a shaft south of the south Government Pier, it being provided with two openings, one connected to the present 24-inch inlet pipe and the other available for connection, should it be deemed advisable to install a second inlet main extending farther into the lake. This shaft is connected by a tunnel running under the harbor entrance, to the wet-well shaft in the plant. An emergency intake is provided for use in case of trouble in the present intake. The plant is designed on the duplex plan, so that when required either half may be run. Arrangements are provided to permit crossing over units of each half. The raw water pumps discharge through two parallel Venturi meters, one for each side, into cast iron grit chambers, from which the water flows into the primary aerator channels.