Geo-Graf, Inc. - Frequently Asked Questions

Geo-Graf Answer: It's solely dependent upon the subsoil properties of a particular site. Each project site is different. We might be able to detect utilities and other targets up to 15' below grade at one site; but using the same equipment and the same settings, at another project site we might only be able to detect objects 4' below grade. Within our service area and a site containing excellent subsoil conditions, the maximum we'd be able to detect subsurface objects is typically 12' to 15' below grade.

Geo-Graf Answer: GPR is a bit different from other geophysical technologies in that its successful use is very dependent upon the experience, knowledge, and skill-level of the operator. It's not a piece of equipment that somebody can take out of the box, read the instruction manual, and begin using (although that is exactly what a lot of companies do). GPR is often hard to use and its even more difficult to interpret the data. There are no universal certifications, degree programs, or training courses to become a "GPR operator". Jay Graf, Geo-Graf President, has over 20 years experience in performing GPR investigations and is one of the leading experts in its use and application. We use GPR almost on a daily basis and typically collect and record 5,000 to 8,000 data profiles every year. In addition, at Geo-Graf you won't meet with upper-level management to set up the project and then have to deal with inexperienced entry-level technicians in field. We know proper equipment use and data collection makes or breaks a project. That's why Jay Graf will personally conduct the investigation at your project site. That's why we can legitimately say; "We can often succeed where others have failed".

Geo-Graf Answer: Our rates are based on a per field-day basis and include site mobilization, the field investigation, site demobilization, data review and post-processing, CAD mapping, and report deliverables. The number of field days per project is dependent upon the search area size and scope of work. Cost quotes are taken on a project-per-project basis, but typical one-day project would cost $2,000 to $3,000. For smaller projects located within 50 miles from our office, half-day rates are usually available. Please contact us to describe your project for a specific cost quotation.

Geo-Graf Answer: Dependant upon the scope-of-work, we'll field-mark the detected findings. For most projects, data review and processing is then conducted at our office. We can incorporate the investigation's findings into an existing CAD mapping file (if provided) or create a new CAD map based on our field measurements. We'll prepare a project-appropriate report that includes representative GPR data profiles of significant detected features. The deliverable package will contain two bound hard copies of the report and full-color plan-view plots up to size ANSI E. Electronic files of the report and mapping deliverable will be sent via email and/or on CD. Typical turnaround is 2 to 3 weeks from the last field-day.

Geo-Graf Answer: No. Not because we don't want to, but because it's technically impossible. Due to the nature of geophysics and subsoil properties beyond our control, no nonintrusive geophysical technique can be guaranteed to detect 100% of all features. We're not afraid to tell you that we'll miss things and sometimes get fooled by the data. However, what we try to do (when applicable) is incorporate and correlate the data from the four most reliable techniques in the industry, combine that with our unequaled "real-world" experience, to provide the best nonintrusive investigative service in the marketplace. Our disclaimer is on every proposal, report and map we produce. In summary it states that we'll make a professional attempt to present you with the most accurate and reliable information that can be obtained from our instruments. Even though we utilize different nonintrusive subsurface delineation techniques for most of our investigations, subsurface features could, and occasionally, do go undetected.

Geo-Graf Answer: By hiring us to survey your project site before construction, excavating, or drilling we can help prevent cost overruns, work stoppages and unexpected repairs due to the striking of unmarked, unknown subsurface features. By providing you with an accurate field-markout and CAD-based map, we can save you thousands, even for smallest of projects. Clients also utilize our services during the design phase of projects, incorporating our findings into their plans in order to identify and minimize potential conflicts while maximizing efficiency once construction begins. Our findings are also used by bidding contractors in order to provide more accurate proposals. In another example, having a Geo-Graf UST Search before buying a commercial or industrial property can literally save you millions in liability and clean-up fees if a leaking old tank is found after you take ownership.

Geo-Graf Answer: For a geophysical investigation, delineation of a utility, tank, or other subsurface feature, we can be as precise as paint a mark on the ground. Although we're not surveyors, the horizontal accuracy of our field-marks and CAD maps are precise enough to facilitate most excavation, construction and design projects. If the highest precision is needed in terms of CAD mapping and feature depth elevation, GGI recommends having a professional surveyor map our field-marks and a vacuum excavator "pot-hole" specific utilities or features to measure precise depth elevations.

Geo-Graf Answer: A one-call markout is only good for specific utility company-owned lines, typically from the street to the meter or valve. "Private utilities" are those utilities from the meter/valve to your equipment or building. Also they only use one technique, an RF locator, to detect and markout their utilities. RF can only detect metallic utilities. RF detection of nonmetallic lines, like HDPE gas lines, can only be done if the line was installed with a "tracer wire". Often these wires are damaged during backfill or were never even placed in the same trench as the utility. At Geo-Graf, we use four different detection techniques for utility locating. GPR is the only technique that can locate nonmetallic utilities like PVC, terra-cotta, fiberglass, or concrete pipes - regardless of the existence of a "tracer wire".

"I trust my prints"

Famous last words! We've lost count of how many times people swore by their prints and then we'd end up finding 2, 3, or 10 previously unknown utility systems that extend directly through their work area. In the rare case we don't happen to find any surprise utilities or anomalies and only end up verifying your existing prints, the fact that you've conducted a subsurface investigation before excavating impresses your clients, safety gurus, and insurance companies.