Collapsing Building
			 Close Ups


		 # 1 = Dust by Wall Rubs (tondb)


			 |      |
			 |      |
     . Airborne          | Wall |              . Non Airborne
       Dust #1           |      |                 Dust #1
		      <- |      | ->
	      .. . .     |      |   . .
	     . .. . .    |______|  . *
	      . . .. * *  ______  . . *
	       . .  * * *|      |* * * . .    * Chunks
		 . .* * .|      | * * . .        for
		      *..| Wall |.. ** .       Crushing
  * Chunks for Rubbing . |      |. ****
       on Pile          /|      |______________________________   ___
		       /*        ______________________________    |
		    L /**        ______________________________    |
		     /***        ______________________________    Hw
		    /****        ______________________________    |
		   /*****        ______________________________   ___

		     Rc



	   Secondary  Dust Generation # 2 & 3


			 |      |
			 |      |     Dust #3
      Dust #2            |      |       by
	by               |      |      Slab
       Pile              |      |      Crush  (tonbcp)
       Rub               | Wall |_____________________________
     (tondc)             |      |*
			 |      |**      .     .
			 |      |***      .  .     . Temporary
			 |    Ht|**** ==>  .    .     Trapped
			 |      |*tbs*   .   .        Dust #3
      . Airborne         |      |******    .   .
	Dust #2         /   _    ______________________________
	  . . .      **/*        ______________________________
	 .  .       **/**   H    ______________________________
       .  .. .<=== **/***   w    ______________________________
	. . .      */****        ______________________________
	.         L/*****   _    ______________________________

		     Rc         |< Rb >|