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Part 15

Part 15 of Wonders of World Engineering was published on Tuesday 8th June 1937, price 7d.

Part 15 includes a photogravure supplement showing the Romance of African Copper, which illustrates the article on this subject.

The Cover

“The cover this week’s Part was made from a photograph supplied by the United States Bureau of Reclamation. It gives a striking view of one of the cableways used for transporting material during the building of the Boulder Dam, which was described in part 2.”

One of the cableways used for transporting material during the building of the Boulder Dam

Contents of Part 15

Tunnelling the Hudson (Part 2)

The Craft of the Welder

Lifting Span and Swing Bridges

Romance of African Copper

Romance of African Copper (photogravure supplement)

Building Dover Harbour

The Trans-Siberian Route (Part 1)

Tunnelling the Hudson (Part 2)

The story of the thirty year struggle to complete the Hudson Tunnel beneath the Hudson River, New York. The chapter on this subject is by David Masters, and is concluded from

part 14. This is the third article in the series Below the Surface.

(Pages 433-436)

Lifting Span and Swing Bridges

THE task of building a bridge or viaduct across a waterway frequented by small craft only is generally much easier for the engineer than when the waterway is used by large ships. In such conditions, to provide headroom for ships with a fixed deck bridge when the banks of the waterway are low is almost always out of the question. For one thing it would involve long and costly approaches to reach the desired height. With a low approach, then, some other method has to be adopted. The bascule bridge and the transporter bridge, described in the chapter beginning on page 381, are two types of bridge suitable for the purpose, although they have their limitations.

Examples of two other types are here shown. The upper illustration shows one of the eleven vertical lift bridges across the Welland Ship Canal, in Canada. As its name implies, the deck of this bridge is lifted bodily up out of the way when a vessel has to pass. This particular

bridge is situated at the city of Welland and has a 30-feet roadway. When closed the deck is only 15 feet above the water level, but when it is open it is about 111 feet above the water level. There is a clear channel 200 feet wide to be spanned and the length of the bridge, measured between the bearings, is over 231 feet. The deck is suspended at

the ends by wire ropes passing over large pulleys at the top of the guiding towers, counterweights inside the towers being attached to the other ends of the ropes.

The total weight of the lifting span and counterweights is 2,300 tons. The operating machinery is carried in a cabin situated centrally on the lifting span. Winches pay out and take in wire ropes and are driven by electric motors. The current for these is picked up by a shoe

travelling on conductor wires stretched vertically down the front of the towers. A petrol engine is fitted for use in the event of current failure.

The bridge shown in the lower illustration is of an older type, although it was completed in 1936. A span in the deepest part of the waterway is pivoted on a vertical axis so that it can be swung round to a position at right angles to the roadway and so leave a clear passage for ships at either side.

The bridge shown crosses the River Forth at Kincardine, Scotland, and its total length, with

its approach spans, is over half a mile. The swing span is 364 feet long and when it is open

there are two navigational openings each 150 feet in width; when closed there is a clear

headroom of 30 feet, at high water. The weight of the swing span is 1,600 tons and is taken

on sixty rollers arranged in a circular path. The control cabin is at the centre of the swing

span and the operating machinery is situated in the central pier. The machinery consists of

two 50 horse-power motors, driven by a 160 horse-power oil engine. Photoelectric cells, the

operation of which is described on page 390, indicate when the swing span is in correct

alignment with the approach roads. The roadway is 30 feet wide.

This is the eighth article in the series on Modern Engineering Practice.

 (Page 442)

The Craft of the Welder

Modern industrial welding is a constructional method practised in workshops all over the world. Three principal welding systems are in use, the electric, the oxy-gas and the thermit process. Electric welding may call for temperatures as high as 7,500 degrees Fahrenheit. This chapter is by F E Dean, and is full of interesting explanations of the various welding processes that are used. The principle of electric resistance welding was discovered by accident when Professor Elihu Thomson was giving a lecture in the United States on electricity. One of the fascinating processes described is the metallization process, by which the most delicate of substances can be coated without injury. In this way it would be possible to put a glove of molten steel on the human hand without burning the skin.

(Pages 437-441)

Romance of African Copper:

Photogravure Supplement

“IN OPEN MINES, where copper-bearing ores are near the surface, steam shovels load the ore into railway trucks. The trucks are then hauled to the crushing plant where the ore is crushed and ground to a fine powder before treatment for the extraction of the copper.”


(Page 445)

Building Dover Harbour

The exposed position of Dover made the building of its huge naval harbour a tremendous feat of engineering, calling for much daring and high organizing skill. Harbour building is one of the most interesting feats of the civil engineer. He has the sea to contend with, and the sea is a formidable opponent. One of the largest, and certainly one of the most important examples of harbour building is the National Harbour at Dover. Eleven years were occupied in this work, and the cost of it was about £4,000,000. The position of Dover made the work all the more difficult, because the port is so situated that it is exposed to the full fury of all gales ranging from extreme west to extreme east. In all about two and a half miles of breakwater and sea wall were built. The work is described in this chapter by Harold Shepstone. The harbour was opened by King George V (then Prince of Wales) on October 15, 1909. There is accommodation, in the enclosed water area of 610 acres, for a fleet of large warships and their attendant craft. The harbour works included the extension of the Admiralty Pier, which is used by the regular cross-Channel packets, to double its previous length, thus making it 3,200 feet long. An area of twenty-one acres, too, was reclaimed from the foreshore.

(Pages 453-458)

The Trans-Siberian Route (Part 1)

Despite enormous difficulties imposed by the nature of the country, which included steppes, rivers, lakes, mountains and desert, engineers at last succeeded in linking East and West with a steel highway across the largest stretch of unbroken land in the world. The article is by

C Hamilton Ellis and is concluded in part 16. It is the fifth article in the series on

Railway Engineers at Work.

(Pages 459-460)

You can read more on the Trans-Siberian Railway in Railway Wonders of the World.

Building Dover Harbour

“OUT INTO THE CHANNEL. The Admiralty Pier was extended seawards in the same way as the east arm and south breakwaters were built. On either side of the line of the future wall platforms were mounted on piles to hold the gantry and other cranes. On one of the gantries was mounted a temporary lighthouse which thus advanced as the wall was built.”

(Page 456)

The Ruashi Copper Mine

“A LARGE OPEN COPPER MINE in the Belgian Congo. The Ruashi Mine, which is not far from the “Star of the Congo” and Elisabethville, was opened in 1922. This mine is an excellent example of the system of open working used when the copper ores are to be found near the surface. When the ores are at a greater depth shafts have to be sunk.”

(Pages 446-447)

Romance of African Copper:

Photogravure Supplement


“THE CONCENTRATOR PLANT at the N’Kana Mine, in Northern Rhodesia. The ore is first crushed to a powder and is then put in a vat of water. The water is agitated and a frothing oil is added. A film of oil adheres to the particles of copper and air bubbles form on the copper, causing it to float to the surface and leave the worthless matter suspended in the water.”

(Page 448)

Building Dover Harbour

“LOWERING A CONCRETE BLOCK to the bed of the sea along the line of one of the breakwaters in Dover Harbour. The breakwaters were built of huge concrete blocks, laid on the sea bed and not on a foundation of rubble. The sea bed was first cleared to bedrock with the help of divers working in diving bells such as that shown on the platform to the left.”

(Page 453)

Romance of African Copper

The riches of the Copper Belt in Katanga, Belgian Congo, and of the copper mines in Northern Rhodesia have been won by the efforts of explorers, railway pioneers and mining engineers, who have built up an important industry in a district remote from the rest of civilization. One of the chief virtues of copper as a metal is that, except for silver, it is the best conductor of electricity. Its use, therefore, in this electric age, is extensive for engineering purposes. For thousands of years, however, copper was used as a precious metal and for decorative purposes. The word is derived from the name of the island of Cyprus, where the Romans obtained their copper ore. One of the richest copper-bearing districts in the world is the Katanga Copper belt in the Belgian Congo. Here are numbers of rich copper mines, and in this chapter Sidney Howard describes how the copper is extracted from the ore in the African mines. The chapter is illustrated with a photogravure section.

(Pages 443-452)

The N’Kana Copper Mine, Northern Rhodesia

“THE N’KANA COPPER MINE, in Northern Rhodesia, consists of a vertical central hoisting shaft more than 1,000 feet deep and a smaller but deeper vertical shaft for advance work. Adjoining the central shaft are the buildings, shown above, which house the concentrator and the crushers. The concentration process separates the copper from the worthless matter.”

(Page 443)

Modified Tunnelling Shield

Modified Tunnelling Shield

“MODIFIED FORM OF SHIELD, showing moving cantilever platform. The shield measured

19 ft 6 in inside the tail piece, and was advanced by sixteen 8-in hydraulic jacks. The pressure developed in the jacks corresponded with the amount necessary to force the shield forward, and varied according to the nature of the soil. The shield used by S. Pearson & Sons had been designed to deal with silt only. To make it suitable for working in rock an apron was built extending 6 feet in front of the face of the cutting edge.”

(Page 434)

Oxy-Acetylene Welding

Oxy-Acetylene Welding

OXY-ACETYLENE WELDING upon the cylinder block of a motor car engine. The operator is performing the delicate operation of welding a crack in a valve setting. In this process he works with a blowpipe which is fed with oxygen and acetylene - the two separate pipes can be clearly seen - and he uses the fierce flame to fuse into the casting the feed rod seen in is left hand. After the seat has been welded it is machined to match the other seats. The oxy-acetylene process is used principally for welding cast iron, but is extensively used also for welding steel, aluminium and other metals.”


(Page 439)

Electric welding

Electric Welding

ELECTRIC WELDING AT THE LNER SHOPS, DONCASTER. The operator, protected with helmet, gauntlets and apron, from the fused and superheated globules of metal, is at work on one of the locomotives of the London and North Eastern Railway.”


(Page 441)

The Kincardine swing bridge across the River ForthThe N’Kana Copper Mine, Northern RhodesiaSteam shovels load copper ore into railway trucksThe Ruashi Copper MineThe Ruashi Copper MineThe concentrator plant at the N’Kana Mine, in Northern RhodesiaBuilding Dover HarbourExtending the Admiralty Pier, Dover

Across the River Tom

“SIX STEEL SPANS carry the Trans-Siberian railway across the River Tom, 103½ miles along the route from Obi. The river here is 1,680 feet wide, and the six spans of 280 feet rest on masonry piers. The piers are reinforced by triangular buttresses pointing upstream, to break up ice that floats downstream in winter.”

(Page 460)