Can anyone provide me with any information about the reverse reference to "DONALDSON" on the above 30 mm diameter brass embossed, uniface check. I though this name may be some form of a reference to the pit's pre 1947 owners. However, I understand that before passing into NCB control the pit had only had one previous owner, the Trimdon Colliery Company Limited.

Any information as to what this check is, what it was used for or how old it might be would be greatly appreciated.