The SlideMinder wireline extensometer was developed by Call & Nicholas Instruments, Inc. in 2003 to be a cost effective and user-friendly method of gathering highly accurate slope monitoring data for engineering and safety purposes.

In addition to the SlideMinder wireline extensometer, Call & Nicholas Instruments, Inc. provides a wide range of geotechnical instrumentation such as Goniometers, Manual Extensometers, Slope Stability Prisms, and Slope Stability Prism Targets.

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CNI provides a complete geotechnical testing laboratory capable of performing soil and rock testing in support of engineering programs. The laboratory is staffed by five full-time personnel with over a combined 35 years’ worth of experience in soil and rock testing. CNI’s nonproduction laboratory allows for our engineers to work hand-in-hand with our laboratory technicians to ensure testing programs are uniquely catered to each engineering program and testing results are of the highest quality.

Having our laboratory close-at-hand allows immediate feedback and strong communication between engineer and laboratory technician. Unique samples that many other laboratories would simply discard due to complicated preparations, are prepared and tested by our laboratory under the scrutiny of our engineers to ensure the time and money spent to obtain those samples is rewarded with first-class data.

Our laboratory is equipped with fully automated testing devices. Testing is performed in accordance with the American Society of Testing and Materials (ASTM), the International Society for Rock Mechanics (ISRM), and the British Standards (BS). Our laboratory also has a United States Department of Agriculture soil permit required in order to import foreign soils for testing purposes.


Our laboratory is equipped with:

  • Five small-scale direct-shear machines
  • One large-scale direct-shear machine
  • One 300,000-lbs load frame
  • One 60,000-lbs load frame
  • Instrumentation for strain measurements
  • Full machine shop for sample preparation
    • Two rock-core saws
    • One automated rock-core grinder
    • HQ and PQ-sized core drills
  • A 1,080 sq ft long-term storage warehouse

Testing Capabilities Include:

  • Moisture content (ASTM D2216)
  • Density (ASTM D7263)
  • Proctor compaction (ASTM D698)
  • Specific gravity (ASTM D854)
  • Slake durability (ASTM D4644)
  • Atterberg limits (ASTM D4318)
  • Cone penetrometer (BS 1377-2)
  • Sieve analysis (ASTM D422)
  • Hydrometer analysis (ASTM D422)
  • Small-scale permeability (ASTM D2434)
  • Small-scale direct-shear (ASTM D3080)
  • Small-scale fracture shear (ASTM D5607)
  • Large-scale direct-shear (ASTM D3080)
  • Point load (ASTM D5731)
  • Unconfined compressive strength (ASTM D7012)
  • Brazilian disk tension (ASTM D3967)
  • Undrained/unconsolidated triaxial strength (ASTM D7012)

CNI utilizes a system of continuous solid fiberglass rod to precisely install instrumentation in boreholes of any inclination between vertical and horizontal. Installations can be done in any kind of drill hole.

  • A high-strength fiberglass rod is used to place sensors inside boreholes.
  • Vibrating Wire Piezometers (VWP), Time Domain Reflectometer (TDR) cable, or any other borehole instrumentation can be installed to the required depth
  • Installation capability up to 5000 feet (1524 m) deep
  • Rapid installation using the continuous carrier rod – over 1000 ft (328 m) per hour
  • More reliable than other methods due to the high tensile strength of the carrier rod, reduced material handling, and absence of joints
  • Install capabilities in conventional rotary, RC, and NQ or larger core holes

Our Installation Services Include:

  • A full range of services including drill hole and piezometer planning, VWP and data logging equipment installation, and long-term monitoring
  • Installation by experienced CNI engineers who provide close supervision of all aspects of the installation, including hole grouting and completion
  • Comprehensive borehole logs and installation notes are provided
  • Services available 24 hours a day, 7 days a week