Mix the salt and egg whites in a large bowl to create a stiff, snow-like consistency. Cover the Prime Rib Roast with pepper and the herbs. Place one third of the salt in a pan and place the roast on top. Pack the rest of the salt around the roast until it is completely covered and encased tightly. Cook in a 350 degree oven for 25 minutes per pound of roast or until a thermometer reads 130 degrees. Remove from the oven and let stand 30 minutes before slicing. Remove the salt crust at the table with a hammer for a dramatic flair.