In districts where mineral extraction is a permitted use, the following shall apply:
   (a)   In the case of open excavation, there will be required a substantial fence with suitable gates completely enclosing the portion of the property in which the excavation is located, and such fence shall be located 40 feet or more distance from the edge of such excavation.
   (b)   The slope of the material in such sand, gravel or other pit shall not exceed the normal angle of repose of such materials, and the plane of such angle of repose shall not come nearer than 40 feet to any property lines.
   (c)   In the case of a quarry or other excavation in rock, there will be required a substantial fence, with suitable gates at all points a distance of 40 feet or more from the face of any quarry walls.
   (d)   Rock crushers, cement plants or other crushing, grinding, polishing, or cutting machinery or other physical or chemical process for treating the product of such quarry may be prohibited.
   (e)   No such quarry shall be nearer than 40 feet to any property boundary line, street or highway right-of-way line.