Depicted below is the area where the Mile-Hi Skydiving airplanes "shall" remain while operating.  This is known as the "LMO Parachute Operations Area" as defined by the FAA facility who controls this airspace (Denver Terminal Radar Approach Control or TRACON).  In addition, they must also remain below 17,900 feet above Mean Sea Level (MSL).

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As you can see, this area is quite large and extends west to Hwy 7/36 and south to Gunbarrel and Boulder Reservoir.  This area is located where it is based on other traffic that traverses the area, most notably Denver Intl arrivals from the northwest and departures to the west.  This area is literally wedged in between those operations.  There is no other place north or east to move the skydiving operations.