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NAD approaches each project as a collaborative team effort working closely with the client to minimize the inherent risks of subsurface construction and maximizing the construction dollar.

NAD's process delivers optimum efficiencies and reduces risk
  • Rock grouting and compaction grouting expertise allows greater access to the rock formation through unconsolidated materials.
  • Shaft development is performed ahead and independent of any underground work keeping projects isolated from underground operations.
  • Fully developed shafts are lined according to application and material efficiencies. Final liners available in steel, concrete or composite materials.
  • On site equipment and expertise to expedite site prep

Project Execution 
  • Pre-Excavation Grouting Techniques Enhance Ground Stability
  • Surface Casing Provides Access Through The Overburden
  • Pilot Hole Development:
    • Controls Vertical Alignment
    • Verifies Pre-Excavation Grouting Program
  • Shaft Reaming Process Utilizes Reverse Circulation Drilling
  • Shaft Lining Is Installed Safely From The Surface
  • Tremie Grouting Of Annulus Secures Lining In Its Final Position
Large Diameter Shaft Solutions
Blind Bore Drilling

NAD provides the global market with shafts approaching 20' (6m) in diameter and 2000' (600m) deep. This unrivaled expertise is used to meet the growing demands for larger diameter ventilation and access shafts for sewer systems, tunnels, infrastructure, and raw water intake.

  • Competitive advancements in reverse circulation technology maximize safety and minimize cost
  • Appropriate ground stabilization reduces surface and strata related risks
  • All work safely conducted at the surface
Small Diameter Shafts Solutions
Blind Bore Drilling

NAD's small diameter shafts provide underground operations with the shortest possible route for utilities, such as electrical power, pneumatics (air) and communications.

Ground stabilization for shaft development is self-performed by NAD's in house team which eliminates the need for additional subcontractors and reduces costs. Analysis, design and execution for our clients site-specific task are performed in house, in real time.

Vibratory Pile Hammer

NAD's 390-Ton Driving Force Vibratory Pile Hammer Installing 16.5' Diameter Surface Casing

  • 390 - Tons Driving Force
  • 17.5' Diameter Casing Capacity
  • 14,000 in-lbs Eccentric Moment
  • 1,400 VPM Frequency
  • 1' Amplitude
  • 300 Ton Clamping Force
  • 150 Ton Pull Capacity
  • 62,000 lbs. Weight
Raise Bore Drilling

When schedule and geological conditions require an alternative to conventional shaft sinking, industry professionals in mining and civil construction trust NAD. Vertical, or nearly vertical, openings used for ventilation,man ways, and ore and waste transportation for operating mines
Shaft development for civil construction projects.

  • Vertical deviations of no more than 1%
  • Surface and underground setup provided
  • Reduced disturbance of surrounding rock in unstable or frozen ground conditions, raise boring dramatically lowers the cost and expedites completion of the raise
  • Minimal environmental disturbance
  • Limited interruptions to traffic or services

NAD provides a wide range of shaft development options, please call for current diameter and depth specs