Headframe
Encyclopedia
A headframe is the structural frame above an underground mine shaft
. Modern headframes are built out of steel, concrete or a combination of both. Timber headframes are no longer used in industrialized countries
, but are still used in developing nations
. Traditionally steel headframes are used when a drum hoist is employed, and concrete headframes are built for friction hoists, however a steel headframe can be used with a friction hoist for shafts with a smaller capacity and depth.
) does not exceed 50 m. Steel headframes are more adaptable to modifications (making any construction errors easier to remedy), and are considerably lighter, requiring less substantial foundations. As steel headframes are easier to design, they have the potential to utilize "off the shelf
" design tools. Construction of a steel headframe can be easily interrupted and restarted if necessary for statutory holidays or bad weather, where slip forming
concrete is not. Upon mine closure and mine reclamation
a steel headframe is easier to demolish and may have value as scrap metal
.
A recently erected steel headgear in the Zambian copper belt town of Chililabombwe
at the Konkola number 4 shaft, has total height of 81 metres to the top of the maintenance crane rail, with the centre-line of the head sheaves at 71 metres above collar, making it the highest steel headgear in Africa.
Concrete headframes require less maintenance and are less susceptible to corrosion than steel headframes. There is much less waste of concrete during construction of a concrete headframe than there is of steel in construction of a steel headframe. Concrete headframes provide an enclosure upon construction, whereas steel headframes require cladding
and insulation to protect from weather. Concrete headframes are less susceptible to vibrations, and sway less during high winds. Concrete is usually more readily available than steel (except in remote locations), and the price is predictable, whereas fabricated steel prices can be volatile.
in Britain are both examples of areas which are now associated with headframes due to the large number constructed to mine coal
during the Industrial Revolution
. Most of these headframes have now been removed although both regions have turned non-operating mines with headframes into national museums; the German Mining Museum in Bochum
and Big Pit National Coal Museum in Blaenavon
. Sporting teams from former coal mining regions such as Llanharan RFC
and Cilfynydd RFC
have headframes included in their club badges.
Shaft mining
Shaft mining or shaft sinking refers to the method of excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom....
. Modern headframes are built out of steel, concrete or a combination of both. Timber headframes are no longer used in industrialized countries
Developed country
A developed country is a country that has a high level of development according to some criteria. Which criteria, and which countries are classified as being developed, is a contentious issue...
, but are still used in developing nations
Developing country
A developing country, also known as a less-developed country, is a nation with a low level of material well-being. Since no single definition of the term developing country is recognized internationally, the levels of development may vary widely within so-called developing countries...
. Traditionally steel headframes are used when a drum hoist is employed, and concrete headframes are built for friction hoists, however a steel headframe can be used with a friction hoist for shafts with a smaller capacity and depth.
Benefits of steel headframes
A steel headframe is less expensive than a concrete headframe providing the height (defined as the vertical distance from the collar elevation to the center-line of the highest head sheavePulley
A pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...
) does not exceed 50 m. Steel headframes are more adaptable to modifications (making any construction errors easier to remedy), and are considerably lighter, requiring less substantial foundations. As steel headframes are easier to design, they have the potential to utilize "off the shelf
Commercial off-the-shelf
In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...
" design tools. Construction of a steel headframe can be easily interrupted and restarted if necessary for statutory holidays or bad weather, where slip forming
Slip forming
This article is about pouring concrete in moving forms. See Slipform stonemasonry for another type of slip forming.Slip forming, continuous poured, continuously formed, or slipform construction is a construction method in which concrete is poured into a continuously moving form...
concrete is not. Upon mine closure and mine reclamation
Mine reclamation
Mine reclamation is the process of creating useful landscapes that meet a variety of goals, typically creating productive ecosystems from mined land...
a steel headframe is easier to demolish and may have value as scrap metal
Scrap Metal
Scrap Metal were a band from Broome, Western Australia who played rock music with elements of country and reggae. The members had Aboriginal, Irish, Filipino, French, Chinese, Scottish, Indonesian and Japanese heritage. The band toured nationally as part of the Bran Nue Dae musical and with...
.
A recently erected steel headgear in the Zambian copper belt town of Chililabombwe
Chililabombwe
Chililabombwe is a city located in Zambia's Copperbelt Province. The name means 'place of the croaking frog'.The main economic activity is the mining of copper....
at the Konkola number 4 shaft, has total height of 81 metres to the top of the maintenance crane rail, with the centre-line of the head sheaves at 71 metres above collar, making it the highest steel headgear in Africa.
Benefits of concrete headframes
Cladding (construction)
Cladding is the application of one material over another to provide a skin or layer intended to control the infiltration of weather elements, or for aesthetic purposes....
and insulation to protect from weather. Concrete headframes are less susceptible to vibrations, and sway less during high winds. Concrete is usually more readily available than steel (except in remote locations), and the price is predictable, whereas fabricated steel prices can be volatile.
Symbolism
Headframes have become prominent features in historic mining regions. The Ruhr district of Germany and the South Wales ValleysSouth Wales Valleys
The South Wales Valleys are a number of industrialised valleys in South Wales, stretching from eastern Carmarthenshire in the west to western Monmouthshire in the east and from the Heads of the Valleys in the north to the lower-lying, pastoral country of the Vale of Glamorgan and the coastal plain...
in Britain are both examples of areas which are now associated with headframes due to the large number constructed to mine coal
Coal mining
The goal of coal mining is to obtain coal from the ground. Coal is valued for its energy content, and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United States,...
during the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...
. Most of these headframes have now been removed although both regions have turned non-operating mines with headframes into national museums; the German Mining Museum in Bochum
Bochum
Bochum is a city in North Rhine-Westphalia, western Germany. It is located in the Ruhr area and is surrounded by the cities of Essen, Gelsenkirchen, Herne, Castrop-Rauxel, Dortmund, Witten and Hattingen.-History:...
and Big Pit National Coal Museum in Blaenavon
Blaenavon
Blaenavon is a town and World Heritage Site in south eastern Wales, lying at the source of the Afon Lwyd north of Pontypool, within the historic boundaries of Monmouthshire. The town lies high on a hillside and has a population of 6,349 people...
. Sporting teams from former coal mining regions such as Llanharan RFC
Llanharan RFC
Llanharn Rugby Football Club is a rugby union club based in Llanharan, South Wales. Llanharan RFC were formally established in 1891-92 when Llanharan was little more than an agricultural hamlet. The earliest photograph on the club house wall is dated 1898...
and Cilfynydd RFC
Cilfynydd RFC
Cilfynydd Rugby Football Club is a Welsh rugby union club based in Cilfynydd in Pontypridd, Wales. The club is a member of the Welsh Rugby Union and is a feeder club for the Cardiff Blues..-Club badge:...
have headframes included in their club badges.