BS-3618-11-1967.pdf

BRITISH STANDARD BS 3618: Section 11: 1967 Glossary of Mining terms Section 11: Strata control Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 This British Standard, having been approved by the Colliery Requisites Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on 29 December 1967 © BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference CRE/17 Draft for comment 66/18815 ISBN 0 580 34516 5 Co-operating organizations The Colliery Requisites Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government department and scientific and industrial organizations: Association of Mining Electrical and Mechanical Engineers* British Electrical and Allied Manufacturers Association British Iron and Steel Federation Electric Cable Makers Confederation Federation of Associations of Mining Equipment Manufacturers Institution of Electrical Engineers Institution of Mechanical Engineers Institution of Mining Engineers* Mechanical Handling Engineers Association Ministry of Power* National Association of Colliery Managers* National Coal Board* The Government department and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: University of Birmingham University of Leeds University of London University of Newcastle-upon-Tyne Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 © BSI 02-2000i Contents Page Co-operating organizationsInside front cover Forewordii Section 11. Strata control1 Figure 1 Subsidence terms8 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 ii © BSI 02-2000 Foreword In preparing this glossary the object has been to standardize and to co-ordinate the technical terms in current use in mining in the United Kingdom. Although the majority of the terms are necessarily concerned with coal mining, account has been taken of certain terms used in other forms of mining and of quarrying. During the long period which has elapsed since the publication of the last authoritative mining glossary1), many new terms have come into use. The need for the present glossary has arisen from the widely varying interpretation and use of such new terms, and the prevalent use of more than one synonym, some purely local in origin, to indicate specific meanings. The glossary will initially be issued in a number of sections, according to subject matter, and will include terms relevant to the following fields of mining: Planning and Surveying; Ventilation; Boring and Exploration; Drainage; Geology; Drilling and Blasting; Electrical Engineering and Lighting; Winning and Working; Transport; Shafts and Associated Equipment; Strata Control. i) Where two or more terms are in use the term which is favoured is given first and printed in heavy type. It is hoped that such preferred terms will gradually displace the non-preferred terms. Where the use of any term is considered to be undesirable it is marked “deprecated”. ii) Taking a broad view of the various sections of this glossary, only terms which have a specific meaning in mining have been included and, generally, where a technical term has an accepted meaning in other fields of engineering it has been omitted; the few exceptions are terms which are of particular and fundamental importance in mining. iii) Purely local terms are not defined, but those of sufficient importance are included as non-preferred terms alongside the preferred synonyms. iv) Obsolete terms are excluded. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) “A glossary of the mining and mineral industry” by A.H. Fay, U.S. Bureau of Mines, Washington, 1920. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 © BSI 02-20001 Section 11. Strata control TermDefinition abutmentThe region adjoining an excavation which is normally subjected to increased stress as a consequence of the redistribution of load. This may be at the front of, or at the sides or rear of a working face. advance pack BUTTRESS PACK A small pack built in advance of the gate side pack to limit the spreading of the adjoining caved waste towards the roadway in a longwall face. anti-flushing shieldsA curtain of bars, plates or chains on the waste side of powered supports to hold back the material which flushes or falls from the caved waste. anti-slewing strutsBars fitted between powered supports to prevent slewing of the supports on gradients. arch girder RING, deprecated A rolled steel section bent into the form of an arch and normally in two or more lengths joined together to form a support for the roof and sides of a roadway. articulated archAn arch in which the component lengths are hinged together. articulated barSee link bar. backfill1. Material which is used to fill the void following extraction of mineral. 2. Overburden replaced after opencast extraction of mineral. 3. Loose material placed behind the shaft wall or the lining of any other excavation. backward hading breaksBreaks whose planes are inclined from the normal to the plane of the seam, towards the goaf. barA support set parallel to the roof. barrier pillarsPillars or strips of coal or other mineral suitably dimensioned and disposed, left unworked for the purpose of dividing a seam or mine into separate working panels or districts. bar slide bracket systemA system of support in which roof bars are slid forward on brackets attached to adjacent parallel bars, props being then set to the newly advanced bars. bar slide headA device at the top of a support enabling the support to remain set to the roof while the bar above it is released and slid forward to a new setting position. bar slide head systemA system of support in which roof bars are moved forward through bar slide heads, the props continuing to carry load. bed separationThe moving apart of stratified beds caused by excavation. breaking-off lineThe support line at the rear edge of a longwall face along which the roof is induced to break. breaking-off propsProps set alongside the edge of the intended goaf or of a ripping, to determine the line of break. breaksThe fractures that develop in the roof, floor or sides of an excavation, due to deformation of the surrounding strata. bump CRUMP A sudden and heavy release of strain energy in the major body of rock surrounding a mine working, resulting in displacement of the strata. buttress packSee advance pack. cambered girderA curved roof bar set in a roadway with its convex surface to the roof. cantilever barA roof bar projecting forward to support the roof beyond the propped area. capSee lid. capsuleSee hydraulic load cell. catch prop JACK PROP, deprecated A supplementary prop not forming part of the planned support system. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 2 © BSI 02-2000 TermDefinition cavingThe process of permitting the roof or hanging wall to collapse into the space from which coal or mineral has been excavated. chockStrong roof support consisting of layers of hardwood or a steel structure. (See also hydraulic chock.) chock propA heavy duty prop normally erected to induce caving or to provide additional support in a roadhead. cleavage1. In a crystalline material one or more series of parallel planes along which the mineral tends to split. 2. In a rock, definite parallel closely spaced planes along which it may split, and which may be highly inclined to the bedding planes. cogA roof support built from interlaced layers of wood and usually filled with dirt. competent bedsBeds which have physical characteristics such that they respond to tectonic forces by folding and faulting, rather than by crushing and flowing. (Competent beds are relatively strong and incompetent beds relatively weak.) convergenceMovement of roof and floor towards each other after removal of mineral. The rate of convergence is measured as either: 1) the convergence for a given advance of the face, or 2) the convergence in a given time. convergence recorderA device for measuring and/or recording the amount by which roof and floor approach each other. coupled barSee link bar. creepThe property of certain rocks of undergoing progressive deformation with time when subjected to sufficiently high constant stress. crownThe top of a roadway or arch girder. crumpSee bump. crush blockA block of soft material inserted between a support and the roof, or floor, between two members of a support system, or incorporated within a brick wall, to permit yield and so reduce deformation of the support. depth pressure SUPERINCUMBENT LOAD An assumed pressure due to the overlying strata. In Coal Measures strata normally taken as 1 lbf/in2 (0.007 kgf/mm2) per foot of depth. dint1. A place where material is removed from the floor of a roadway to increase height. 2. To cut away the floor to make height. dome theoryThe theory of rock mechanics which suggests that a wide excavation underground produces a surrounding dome shaped region within which the rock is broken. draw roofSee following roof. drummyThe hollow sound emitted when loose rock forming part of the roof, floor or sides of an excavation is struck. dummy gate DUMMY ROAD, deprecated A road which is formed but not maintained behind a long-wall face, to provide material for building intermediate packs. dynamometer propA prop which is capable of indicating or recording the load which it is carrying. early bearing propA yielding prop which is designed to accept its maximum load soon after it is set (cf. late bearing prop). epicentreIn mining, the place of origin of a rock burst. fallLoose material which has fallen from the roof or sides of an excavation. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 © BSI 02-20003 TermDefinition flat jackA hydraulic pressure device used to impose measured load on a support or rock in situ. floor boltSee rock bolt. floor penetrationThe penetration of loaded supports into the floor of the seam. floor strengthSee load bearing capacity. flushing1. The displacement of loose material from the waste to the supported area. 2. The crumbling of the roof or sides around the supports in an excavation. following roof DRAW ROOF RAMBLE, deprecated A layer of roof which falls as coal is excavated, or soon after. forepolingThe use of girders or bars projecting forward in cantilever as temporary supports beneath newly exposed roof. forepoling bracket HORSEHEAD BRACKET A bracket used for the attachment of a forepole to a permanent support, and designed to permit a girder to be slid forward as excavation proceeds. forward (front) abutmentPressure abutment in advance of a working face. (See abutment.) forward hading breaksBreaks whose planes are inclined from the normal to the plane of the seam, towards the face. frame supportA support consisting of a base frame, two or more legs and a roof bar. friction capA replaceable cap, made of material having a high coefficient of friction, which is fitted to the prop head. friction propA roof support, the yield of which is controlled by a device depending for its operation upon friction between parts of the prop. front abutment pressureSee abutment. goafSee Winning and Working section. goal post supportA frame support having two legs set usually at the ends of the bar. gutterThe narrow extension in height of a roof fall. harmonic extractionThe working of one or more coal seams by means of a special layout and time sequence of extraction, the aim being to lower the overlying surface with minimum of flexure, causing thereby a minimum of damage. head treeSee lid. heave1. Upward movement of the floor. 2. See Geology section. holing spragSee nog. horsehead bracketSee forepoling bracket. horsehead girderA girder used for forepoling in a roadway. hydraulic chockA large diameter hydraulic prop for heavy duty. hydraulic load cell CAPSULE, deprecated A load measuring device with a hydraulic system of load indication. hydraulic propA roof support dependent for its erection and yield under load on a hydraulic system embodying a hydraulic pump and relief valve. hydraulic stowingFilling or partly filling of a goaf with waste material transported underground in a hydraulic suspension. immediate roofIn coal mining, the roof immediately above an excavation which is carried by the supports (cf. nether roof). jack propSee catch prop. key supportsSpecial supports installed at intervals and used to regulate the position of other powered supports on an inclined longwall face. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:14:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3618:Section 11:1967 4 © BSI 02-2000 TermDefinition laggingConcrete, steel or timber, etc., placed between or behind permanent roadway supports. lamellar propFriction prop with a number of laminated members affording several friction surfaces. lateral roof movementRelative movement along the plane of the seam, between the roof and floor in longwall working. late bearing propA yielding prop which is designed to accept its maximum load late in its loading cycle. leg1. A prop in a powered support unit. 2. The lower member of a roadway arch. lid CAP HEAD TREE, deprecated A compression piece usually of wood placed between a prop and the roof, or between a prop and a bar. link bar COUPLED BAR ARTICULATED BAR, deprecated A roof bar which is capable of being coupled in line to another bar and is held in position against the roof by means of a wedge or a shoe. load bearing capacity (1) FLOOR STRENGTH ROOF STRENGTH The inherent resistance of the mine floor or roof to penetration by supports. load bearing capacity (2)The resistance offered by a roof support at its point of yield or failure. load sheddingIn a support, a sudden and unintentional loss of resistance to load. mechanical stow