aquilacavallo is correct. These are Bhutan half rupees, formerly called debs but now called matams. Here's a paper that might help identify them further.
Coinage in Bhutan by Nicholas Rhodes
http://mms.thlib.org/typescripts/00...043/1560.pdf
Coinage in Bhutan by Nicholas Rhodes
http://mms.thlib.org/typescripts/00...043/1560.pdf