[...]
The following shall apply as regards the Federal Republic of Germany:
(a) The periods of coverage to be taken into account under Article 12 shall be assigned to that branch of insurance whose institution is responsible for determining entitlement to a pension if only German legislation is applied. If, according to the foregoing, the Miners’ Pension Insurance is the competent institution, periods of coverage completed under the legislation of Canada shall be taken into account for the Miners’ Pension Insurance only if they were completed in a mining enterprise in underground operations.
(f) With regard to the termination of a miner’s compensation benefit (Knappschaftsausgleichsleistung) for a miner who has given up employment as a miner, a Canadian mining enterprise shall be considered equivalent to a German mining enterprise.
10 With reference to Article 13 of the Agreement:
(b) Mining enterprises within the meaning of subparagraph (a) of Article 13 are enterprises which mine minerals or similar substances or, predominantly in underground operations, stones and earths.