Note: The following is not a verbatim transcript of the Zoning Hearing Board meeting; it is simply one person’s summary of the major points made by those involved in the hearing process.  For that reason, quotation marks are not used unless a direct quote was recorded.  For information about obtaining an official ZHB transcript, contact the New Hanover Township office.

Since Mr. Bob Brant’s witness, Mr. Thomas J. Comitta was not able to attend the meeting, he presented Mr. Joseph G. Casey, a geologist employed by Mignatti Company. Casey is director of land approvals and acquisition and responsible for directing land development activities and acquisitions.  He interfaces with DEP and EPA. Before Mignatti, worked as consulting geologist. VP of Geosciences.

Casey stated that he reviewed the transcripts of meeting with Gibraltar Rock Inc.’s (GRI) witnesses who dealt with geology.  He also reviewed the reports submitted as exhibits covering their data.  He also reviewed the borehole and core logs, and the 72-hour pump hole test data. He also mentioned that he reviewed drill data and the orientation of the rocks.

Brant asked him to define “orientation.” Casey said that in sedimentary rock it’s the way the rock is tilted.

Brant and Casey introduced a series of exhibits that superimposed markings on previous exhibits introduced by GRI. The first was township exhibit T29, which is a marked up A27.  Casey contends that the position of the rock is critical and that the angle and depth is important for the integrity of the walls of the mine pit.  Much of his testimony was trying to show that GRI’s data was inaccurate, and that it did not show the correct slope of the rock as it lies underground.  He contends that if you dig a quarry pit in rock that is sloped, that there is a chance for the quarry pit walls to collapse. Casey also showed township exhibit T30, which is a marked up A27, plates 3 of 4.  On this map there were a number of different lines marked to show the topography of the underlying stone.  The lines are identified using letters A through D, and are marked with a beginning and end, for example:

Line A is marked from beginning, point A to end, point A’ (A prime). 

A___________________________________________________A'

Casey went on to explain that when you create these types of maps that the scale should be the same horizontally as it is vertically. For example, to show the proper dimensions and orientation, a map that uses one inch to equal 200 feet horizontally should also use one inch to equal 200 feet vertically.  This is called a 1:1 projection.  If it’s not a 1:1 projection then the maps are inaccurate.

Brant then asked Casey to make conclusions on map lines A/A’, B/B’, C/C’, and D/D’.  Casey said that A/A’ does correctly shows a 1:1 projection, but was concerned that there are inaccuracies of measurement (one line was actually 65’ longer than portrayed on the map). Casey is concerned that if there are other inaccuracies that the geology of the plotted area is inaccurate.

Casey said that B/B’ is incorrect. On the horizontal, one inch equals 200 feet, but on the vertical one inch equals 100 feet.  He concluded that because of the exaggerated scale the location and size of the rock beds is inaccurate.

Casey said that C/C’ does correctly shows a 1:1 projection, but that D/D’ is exaggerated the same as B/B’.

The next part of Casey’s testimony dealt with the number and spacing of bore holes along these lines A/A’ through D/D’.  He said that along A/A’, which is approximately 4000 feet, that there were only two boreholes.  Along B/B’ (3900 feet) there were three boreholes on the line and one other. Along C/C’ (2170 feet) there was one borehole on the line and one other. And, on D/D’ (2650 feet) there were three holes in a cluster.  Casey concluded that there weren’t enough boreholes drilled to show the correct view of the rock bed. He said that if he wanted ‘clean’ data (i.e. accurate data), that he would have drilled more boreholes.

Brant asked him how deep a borehole went and he said about 400 feet. Brant asked how much it cost to drill boreholes and he said approximately $45/foot, or about $18,000 per borehole.

Brant next asked about the holes that were drilled off of the lines. Casey said that a geologist must make a guesstimate of the underlying rock if a hole is not drilled directly on the line. He said that there were many of these guesstimated holes on the plan.

Casey concluded that we really don’t know from the plans the real slope of the quarry pit and since there could be errors, and with increased truck traffic on Hoffmansville Road, blasting, and vibration, that all of that could cause a slope failure in the quarry pit, in effect, the sides could fall in on themselves.  Casey explained the two types of slope failures: rotational and translational.   He then said that the conditions that exist at GRI increase the potential for a translational landslide.

At this point Brant had no further questions.

See Also:
Summary of the previous meeting (August 27, 2003)