It has been in litigation for over 100 years.  The government offered a relatively minor tribe a payment of $20 million.  They never accepted the payment, the government never paid.  In the early 20th century a lawsuit was filed and the Tribe (s) won.  The US Government was forced to pay.  The tribes (all the tribes, this time) refused the payment.  The money has been earning interest at the same rate as US Treasury bills ever since.  It is a significant amount today.

I do not see any of the Sioux tribes ever accepting that payment.  They contend that the several Laramie treaties guarantee them the hills forever.  They want the hills back.

I understand their desires.  The Black Hills are among my favorite places, too.  

Thanks for a wonderful comment.