Archive for the Category ◊ GPS Monuments ◊

Deeply Anchored GPS Monuments

EarthSafe has constructed GPS monuments throughout remote regions of California, Nevada, Utah, Arizona, Oregon and Washington. These sites range from sea level to over 10,000 feet in elevation. Soil types encountered have been varied from poorly consolidated Miocene beach sand to hard rock. The technical difficulty of these sites includes hardwired to a local power and phone source to fully telemetered sites with cell phone modem, solar power and relay antenna stations.

GPS Monument construction was based on the original Scripps design. The construction methods and techniques used by the Frank Wyatt team were observed first hand in 1995, during the construction of the deeply anchored GPS monument at Table Mountain, CA. This design was modified to meet the specifications of each individual client.

Customized Hydaulic Crawler Drill Rig
Customized Hydaulic Crawler Drill Rig
Versatile on all types of terrain, including here in Mineral, Nevada


A hydraulic crawler drill rig was employed in the field for GPS monument construction due to its agility and maneuverability on all types of terrains and space constraints. If needed, all borings could be done from one position. This is a necessity at remote sites where level space is limited, vehicle access is restricted or native vegetation is to be preserved. With our experience and specialized equipment, we were able to construct monuments at sites most optimal for science, not for the convenience of the construction crew.

Ideal sites are rarely on level ground. Regardless of how level the site is, the crawler drill can place the monument legs accurately within precise specifications for direction and angle allowing the antenna to be mounted level.

Drilling on Uneven Ground
Drilling on Uneven Ground
Regardless of how level the site is, legs can be placed accurately within precise specifications for direction and angle allowing the antenna to be mounted level.


Equipment

EarthSafe used a customized IngersollRand Hydraulic Crawler drill rig equipped with downhole hammers. DTH hammers enable drilling in any terrain while maintaining accurate angles. The DTH hammers were powered by an IngersollRand VHP 400 Air Compressor rated to deliver 400 cubic feet of air per minute at a pressure of 200 pounds per square inch. This provides air pressure to clear a 6 inch diameter hole to a depth of 50 feet, at elevations up to 10,000 feet above sea level. For softer rocks, different bits and drilling fluids were employed to obtain the necessary borings for GPS monument construction. A Chemgrout 550 grout pump ensured complete grouting of the boring from the bottom to the top under pressure using an Ingersoll-Rand P100 Air Compressor. A Miller 225G plus arc welder, two 2″ gas powered trash pumps and a Multiquip gas powered cement mixer were utilized onsite to complete the monuments and ancillary construction. In the field, a 300 gallon water tank provided all required onsite water. The EarthSafe crew was completely self contained which enabled them to install monuments in extremely remote areas.

A Typical GPS Monument Site Configuration:

Typical GPS Monument Site Configuration
Typical GPS Monument Site Configuration





Quality Assurance

GPS monuments installed by EarthSafe followed the original construction design by Wyatt, Agnew and Johnson of Scripps, conforming to the standard of installation specified by the Basin and Range Geodetic Network (BARGEN), Yucca Mountain Project Plate Boundary Observatory (PBO) and Southern California Integrated Global Positioning System Network (SCIGN). All work was directly supervised by an onsite Registered Geologist. Materials used were US manufactured in accordance with FAR 52.2258.

Hard Rock Outcrop Rail NV
Outcrops Consisting of Hard Rock Make Excellent Data Collection Sites
This site in Rail, Nevada was accessible by drill rig and 4X4 pickup truck only


GPS Antenna Rogers Peak Death Valley
Rogers Peak, Death Valley – Elevation 9,994 ft


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