Looks like some money has been set aside to close off mines in Joshua Tree. They state in the article that it will be used for "wildlife friendly" closures, so basically gates and hopefully no backfills.
http://www.nps.gov/jotr/parknews/arra.htm The section mentioning mine closures is at the bottom of the article.
http://www.nps.gov/jotr/parknews/arra.htm The section mentioning mine closures is at the bottom of the article.