A New Hanover man who admitted mixing explosives in his home, causing a blast that rocked his neighborhood, has been given one to four years in Montgomery County Prison. 37-year-old Robert Heintz of Deep Creek Road pleaded guilty to possessing weapons of mass destruction and other offenses.  The explosion gave Heintz a serious hand injury, but no one else was hurt.  After he serves his time he will be on probation for seven years, and he is barred for life from owning any firearms.  He has been in county prison since the incident occurred in November of 2009, so he has served more than the minimum, but he must work with parole officials the develop a parole plan before he can be released.  He must also have a psychological evaluation and comply with any treatment recommendations.