It has been killing me having to keep this under wraps www.1tonnegoldcoin.com
The idea was conceived by Acumen Design as part of their pitch to win the contract to renovate our shop and exhibition. I ran that project until recently and I loved the idea but it was considered impossible (maybe because I wanted it to be 3 tonnes, which would have given it about 1.5m or 5ft diameter). It was our CEO, Ed Harbuz who really got behind it and challenged our guys to work out how to do it, saying that if the Egyptians could make Tutankhamun's gold coffin then surely we could do the same with modern technology.
A few trial runs were made in smaller sizes to get the right mold material and to solve problems dealing with that much molten metal, eg thermal shock. My favorite part of the making video is using a router to cut in the milled edge serrations - if you ever want to "work" pure gold apparently normal wood router bits work just fine.
A silly indulgence to out do the Canadian Mint? Probably, but it will generate some nice publicity and draw tourists to our exhibition and shop so we'll recover the cost of fabrication in time.