Results 51 - 60 of 74

• 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...
• Analytical Investigations of Electromagnetic Location Schemes Relevant to Mine Rescue: Part I - Executive Summary; Part II - Collected Reprints - Analytical Investigations of Electromagnetic Location Schemes Relevant to Mine Rescue
  12/2/1974 - Contract reports
  A summary of past analyses that are relevant to electromagnetic location in mine rescue situations. The analytical results indicated that detection of a trapped miner equipped with a special transmitter is feasible in most situations.
• Waveform Generator-Package and Receiver: Mancarried and Helicopter Receiver Portion
  11/1/1974 - Contract reports
  The report describes the design and building of 15 mancarried and 5 helicopter receivers that are used for trapped miner location during a mine disaster. Helicopters are equipped with six-channel receivers and used to detect transmitters carried by mine...
• 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.
• Electromagnetic Noise in Itmann Mine
  9/1/1974 - Contract reports
  Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Itmann No. 3 Mine, located near Mullens, West Virginia. The electromagnetic environment created by 250-volt dc and 550- and...
• Electromagnetic Noise in Lucky Friday Mine
  9/1/1974 - Contract reports
  Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating Hard-Rock Mine, Lucky Friday Mine, located near Wallace, Idaho. The specific measured results are given in a number of spectral plot...
• 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...