2 edition of How leakage of current from an electric shot-firing circuit causes misfires found in the catalog.
How leakage of current from an electric shot-firing circuit causes misfires
Lee Clyde Ilsley
|Contributions||Hooker, Alva Britt, 1886- joint author., Zellers, Donald Henry, 1904- joint author.|
|LC Classifications||TN1 .U6 no. 471|
|The Physical Object|
|Pagination||ii, 16 p.|
|Number of Pages||16|
|LC Control Number||30026355|
C O N T E N T S PAGE NO. 1ST CLASS (METALL – RESTRICTED)- Explain the terms planning, organizing and control. How an effective manager of a large opencast mechanized mine can skillfully plan, organize and control activities in day-to-day as well as long term basis A large mechanized working is advancing towards a village. current level to initiate electric blasting caps. Current levels above or below the recommended firing level can further increase the scatter in delay cap firing times. Extremely high currents can speed up delay firing times; Near the minimum firing current.
the coal mines regulations, S.R.O dated the 24th October, – In exercise of the powers conferred by section 57 of the Mines Act, (35 of ) and in supersession of the Indian Coal Mines Regulations, , the Central Government hereby makes the following Regulations, the same having been previously published as required by. Good Practice Guidlines | Personal Protective Equipment na.
MINING HAZARDS DATABASE. This Excel workbook applies to Hazards in Coal Mining Operations and their Methods of Control The data in this workbook was compiled by assessing the hazards that could exist in each coal mining activity or element, the mechanisms driving those hazards and controls needed for those mechanisms. The original data came from multi 3/5(1). Free essays, homework help, flashcards, research papers, book reports, term papers, history, science, politics.
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Download PDF Electric Shot Firing In Mines Quarries And Tunnels book full free. Electric Shot Firing In Mines Quarries And Tunnels available for download and read online. How Leakage of Current from an Electric Shot-firing Circuit Causes Misfires.
In fact, a definite minimum quantity of electrical energy is required to fire a detonator, and in practice, a current of amp for 50 milliseconds is required, although in multi-shot-firing the minimum recommended current for the firing of detonators is in the order of amps at 42 volts with a circuit resistance of 30 ohms.
Electric power transmission plants and the use of electricity in mining operations / (Sacramento, Calif.: State Office, A.J. Johnston, Supt. State Printing, ), by Thomas Haight Leggett, A. Book producer Johnston, and California. State Printing Office. Book producer (page images at. How leakage of current from an electric shot-firing circuit causes misfires / (Washington, D.C.: U.S.
Bureau of Mines, ), by L. Ilsley, Donald Henry Zellers, Alva Britt Hooker, and United States. Bureau of Mines (page images at HathiTrust). Common causes of misfires in electric shot firing circuits include the following: > Dirty connections > Faulty exploders > Voltage reduction when firing from the mains > Current leakage caused by: damaged insulation on detonator leading wires - unprotected joints touching conducting strata or a wet face > Exceeding the maximum number of.
How leakage of current from an electric shot-firing circuit causes misfires / C Acrolein as a warning agent for detecting leakage of methyl chloride from a multiple refrigeration system / Falls of roof and coal in the Book cliffs and Wasatch plateau coal fields of Utah /.
Circuit used with an ignitron to deliver a pulse of current of amperes in the forward direction, from the igniter to the mercury, to start a cathode spot and to control the time of firing.
Misfires with Electric Shot Firing: In electric shot firing faulty connections, detonators left-off unconnected, lead wires becoming bare during stemming internally shot-circuited cable / damage. radio-frequency current in an electrical firing circuit is very real, and without doubt can result in extreme consequences.
The hazard is associated with the use of electric detonators and arises when the lead wires to the detonator are unwound and extended into a configuration that resembles and behaves as a dipole receiving aerial,File Size: 20KB.
In wet work, or only slightly damp work wliere the rock or earth contains mineral salts, there may have been enough leakage of current from the cir- cuit to cause the caps in the mid- dle of a series to misfire. Too many electric blasting caps may have been connected in one series, resulting in current leakage from center caps.
Shot firing cables should be tested for any breaks or defect in insulation between conductors by means of ohmmeter before each blast to avoid misfires and. Mines Safety and Inspection Regulations Part 1 — Preliminary. Citation. These regulations may be cited as the Mines Safety and Inspection Regulations 1.
Commencement. These regulations come into operation on the day on which the Mines Safety and Inspection Act comes into operation 1. Terms used in these regulations. Mines Safety and Inspection Regulations Part 1 — Preliminary.
Citation. These regulations may be cited as the Mines Safety and Inspection Regulations 1. Commencement. These regulations come into operation on the day on which the Mines Safety and Inspection Act comes into operation 1.
Terms used. Full text of "SP Handbook on Construction Safety Practices" See other formats. The Engineer-in-Charge shall also be informed by the agent of all cases of misfires, their causes and steps taken in that connection.
General Precautions For the safety of persons red flags shall be prominently displayed around the area where blasting operations are to be carried out. Not taking proper precautions while electric shot-firing.
Well insulated cable of sufficient length is used by shotfirer. Accidental blast of explosives 1 4 14 Due care is taken to protect shot firing cable from coming in contact with any power or lighting or other electric apparatus.
and the 'word "Duplicate" shall be stamped across every such copy. Certificate to be delivered to the manager. - The holder of an Overman's, Sirdar's, Engine Driver's and Gas testing Certificate shall require to deliver such certificate to the manager of the mine where he is for the time being employed in the capacity which requires the possession of the said certificate, and.
(a)(1) The provisions of this Part 77 require that certain examinations and tests be made by a certified person.
A certified person within the meaning of these provisions is a person who has been certified in accordance with the provisions of paragraph (b) of this § to perform the duties, and make the examinations and tests which are required by this Part 77 to.
"Blasting Circuit." A circuit used to initiate expl9sive materials. "Blasting Machine." An electrical device designed to fire electric det-onators.
"Blasting Mat." A heavy mat of woven rope, steel wire, or chain, or improvised from timber, logs, brush, or other materials placed -over. THE COAL MINES REGULATIONS, S.R.O dated the 24th October, – In exercise of the powers conferred by section 57 of the Mines Act, (35 of ) and in supersession of the Indian Coal Mines Regulations.
(a) all alternating current circuits installed in a quarry operation, on a part of a dredge other than a floating treatment plant, and in an underground mine; and (b) all circuits providing alternating current supply to portable, mobile or moveable apparatus.
Penalty: See regulation (2) The earth leakage protection device must —.Misfires. How often do misfires occur (percentage of shots)?
What are the primary causes of misfires: current leakage due to damp conditions or wet-drilling? - incorrect operation of the exploder?
- cable damage? - incorrectly connected circuits (short circuited detonator, loose or dirty connections, omitted detonators)?(a) in relation to every circuit in which alternating current at a voltage exceeding 1, volts is used, effective means is provided for automatically cutting off the supply of electricity from that circuit, with the leakage trip level set as low as is reasonably practicable, but in any case set no higher than 10 percent of maximum current for.