From their website (http://www.randkfireandice.com/Geodes.php):

"We are setting it up to have scheduled digs on the Fourth Saturday of the month.Make your reservations early to make sure you can  dig. And special dig's for clubs and groups by appointment only. You must contact us in advance for rates and dates available. If you  use the form provided and dont get a conformation in a couple day's then contact us Either by email  r_k_alvis@hotmail.com                                 or by calling (660)-754-6361
With the size of your group
and how much time you want to dig"