MOLES SWEEP SIX FROM BLASTERS

THE BUREAU OF RECLAIMATION PERFERS USING MOLES-- BORING MACHINES FOR TRANS-MOUNTAIN TUNNEL EXCAVATION-- FOR THE FOLLOWING REASONS: (1) THE RATE OF EXCAVATION IS FASTER, (2) FEWER PERSONNEL ARE REQUIRED DURING EXCAVATION, (3) LESS OVERBREAK OF THE NEWLY CUT SURFACE--ABOUT 5%, (4) LESS NEED FOR SUPPORTS BECAUSE THE EXCAVATED CIRCULAR SECTION IS MORE NEARLY SELF- SUPPORTING, (5) LESS DISTURBANCE OF SURROUNDING ROCKS, AND (6) EXCAVATION IS SAFER BECAUSE NO BLASTING IS REQUIRED. EQUIPMENT MANUFACTURING INDUSTRIES AND CONSTRUCTION CONTRACTORS ARE BEING ENCOURAGED TO TRY NEW INNOVATIONS ON EQUIPMENT OR METHODS IN ORDER TO REDUCE COSTS AND INCREASE EFFICIENCY. THUS, A NUMBER OF TUNNEL SITES AND THE RESPECTIVE EQUIPMENT AND METHODS, INCLUDING THE SITE CONDITIONS, ARE CITED AS EVIDENCE OF THE SUPERIORITY OF MOLES. FOR THE NAVAJO INDIAN IRRIGATION PROJECT BY A MOLE, THE BETTI-1, WHICH IS 64 FT. LONG AND WEIGHS 280 TONS, WAS BUILT BY THE HUGH B. WILLIAMS MANUFACTURING CO., DALLAS, TEXAS, AT AN ESTIMATED COST OF BETWEEN $750,000 AND $1 MILLION. OUT OF 194 WORKING DAYS THE MOLE WAS IN OPERATING CONDITION 165 DAYS WITH 14 DAYS NEEDED FOR MAINTENANCE AND REPAIRS. AN AVERAGE OF 208 CUBIC YDS. WAS EXCAVATED PER 8 HOUR SHIFT AND 3,127 CUBIC YDS. PER 5 DAY WEEK. THE BLANCO TUNNEL, PART OF THE SAN JUAN-CHAMA PROJECT IN COLORADO, USED MODEL 104-120 BORING MACHINE MADE BY JAMES S. ROBBINS & ASSOCIATES, INC., SEATTLE, WASHINGTON, AT A COST OF ABOUT $330,000. THE AVERAGE VOLUME EXCAVATED FOR DRILLING MAINLY THROUGH SHALE PER SHIFT WAS 1,931 CUBIC YDS. OSO TUNNEL, ALSO A PART OF SAN JUAN-CHAMA PROJECT, WAS DRILLED BY MODEL 104-121A, BY THE SAME MANUFACTURER AS THE BLANCO TUNNEL, AT A COST OF ABOUT $375,000 FOR THE MACHINE. LIKEWISE, THE DRILLING WAS THROUGH SHALE. THE AZOTEA TUNNEL, ANOTHER TUNNEL OF THE SAN JUAN- CHAMA PROJECT, USED THE SAME BORING MACHINE THAT THE OSO TUNNEL USED, ONLY AT A COST OF ABOUT $400,000 FOR THE MACHINE FROM THE SAME FIRM AS ABOVE. RIVER MOUNTAIN TUNNEL ON THE SOUTHERN NEVADA WATER PROJECT UTILIZED A BORING MACHINE MANUFACTURED BY JARVA, INC., SOLON, OHIO, AT A COST OF APPROXIMATELY $500,000 FOR THE MACHINE.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/2642359
• Authors:
  • Bellport, B P
• Publication Date: 1972-5

Media Info

• Features: Photos;
• Pagination: p. 23-7
• Serial:
  • Constructor
  • Volume: 54
  • Issue Number: 5
  • Publisher: Associated General Contractors of America
  • ISSN: 0162-6191

Subject/Index Terms

• TRT Terms: Boring; Costs; Drilling; Excavation and tunneling; Personnel; Shale; Tunneling machines; Tunnels
• Subject Areas: Bridges and other structures; Construction; Finance; Highways; Society;

Filing Info

• Accession Number: 00215570
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 2 1973 12:00AM