Results 251 - 260 of 262

• Technical Bulletin Pager Phones: Installation
  4/1/1975 - Contract reports
  The pager phones used in many underground coal mines are battery-operated, party-line telephones with provisions for loudspeaker paging. The system is two-wire, non-polarized, and is operated by self-contained batteries. A description of the many teleph...
• Technical Bulletin Pager Phones: Circuit Protection
  1/1/1975 - Contract reports
  Wires leading to or from underground facilities can develop hazardous voltages because of lightning exposure. The locations of many mine portals are particularly susceptible to lightning effects. The application of protective devices to limit this poten...
• Research and Development Contract for Coal Mine Communication System: Volume 2 - Mine Visits
  11/1/1974 - Contract reports
  Eight coal mines were visited to determine their communications usage and requirements. Volume 2 details the eight mine visits, along with the conclusions reached following each visit and the final conclusions reached.
• Research and Development Contract for Coal Mine Communication System: Volume 1 - Summary and Results of System Study
  11/1/1974 - Contract reports
  Eight coal mines were visited to determine their communications usage and requirements. Volume 1 summarizes the entire report and includes both a dissertation on the strengths and weaknesses of various available communication techniques and a set of re...
• Research and Development Contract for Coal Mine Communication System: Volume 3 - Theoretical Data Base
  11/1/1974 - Contract reports
  Eight coal mines were visited to determine their communications usage and requirements. Available equipment was surveyed and evaluated to determine its applicability to the needs of the mines. Volume 3 contains all information used in predicting the per...
• Research and Development Contract for Coal Mine Communication System: Volume 4 - Environmental Measurements
  11/1/1974 - Contract reports
  Eight coal mines were visited to determine their communications usage and requirements. Volume 4 describes the propagation measurements made in selected mines during the project, along with findings resulting from these measurements.
• Time and Amplitude Statistics for Electromagnetic Noise in Mines
  9/1/1974 - Contract reports
  The time and amplitude statistics necessary to adequately describe electromagnetic (EM) noise in mines are illustrated through computer soft- ware techniques. They are 1) Allan Variance Analyses (AVA), 2) Interpulse Spacing Distributions (ISD), 3) Pulse...
• Mine Communications: An Overview of the Bureau of Mines Communications Research
  6/1/1974 - Conference papers
  Since 1969, the Department of Interior, Bureau of Mines, has carried out communications research. Research has been directed toward developing emergency and nonemergency mine communications. This paper gives an overview of the progress made in the last ...
• Mine Communications: Proceedings: Bureau of Mines Technology Transfer Seminar, Bruceton, Pa, March 21-22, 1973
  1/1/1974 - Information Circulars
  The Technology Transfer Seminar on Mine Communications held on March 21-22, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pennsylvania, presented information about recently developed equipment, instruments, and techniques for use ...
• Communication Systems Research At Bruceton Safety Research Mine
  1/1/1972 - Conference papers
  An environment monitoring and communication system has been installed in the Bruceton Mine, and research is under way to improve mine safety. Standard day-to-day mine communications are available, along with additional systems installed to permit experi...