Typically backhoes and /or augers are used for shallow soil mixing, (SSM). and sludge solidification. Special attachments exist, or can be manufactured, to insure the quality of the mixing process.
Single auger, multiple augers and other specialized equipment such as trenching machines or the CSM are used for deep spoil mixing.
Inquip owns the backhoes and some of the attachments required for the SSM, but presently will rent the equipment needed for DSM work.