The Holy Prophet of Islam (peace be upon him and his progeny) said:
"اُطْلُبُوا الرِّزْقَ في خَبايَا الأرْضِ"
Seek for your sustenance in the depths of the Earth.1
This instruction was issued by the Holy Prophet of Islam (peace be upon him and his progeny) at a time when the importance of mines and other resources underneath the earth was not known.
Such instructions illustrate the richness of knowledge imparted to us by Islam as well as its emphasis on making efforts to search far and wide so as to exploit for our benefit the abundant natural resources including the ones hidden in the depths of the earth.