Hi Hanse, the inputs are...
GPL share price is $0.73 USD (The silver price has been the key driver for GPL share performance in past 12 month)
USD vs AUD exchange rate 1.38
BDR to GPL conversion = 0.0619
Therefore, BDR shares are currently valued at 6.2 cents AUD.
Below is GPL share performance over the last 12 months. If the merger goes ahead and GPL can retrace back to $1.25 USD (As in June 18) then BDR shares would then be worth ~10.7 cents. For some that's a health profit for others that clawing back losses.
This isn't advise, DYOR.