[TowerTalk] roc..?

[Merlin-7 KI4ILB]

What effect if any would you all think that a driveway made of ROC ( slag rock) would have under the last 18 feet or so of the driven side of  a dipole?
 It is at a right angle to the dipole and about 80 foot long.
 A lot of the slag can be picked up with a magnet.
 Also it it an inverted vee with the middle up about 40' and the ends up about 22' .

 It seems like it would have some kind of effect.

 Just curious...

 Thanks Joe KI4ILB