На церемонии открытия шахты Mr. Х. по традиции бросил туда кошку. Она и нацарапала первые три тонны угля

У меня коряво и не смешно: At the official opening of the mine Mr. X by tradition threw a cat into the shaft and it was the cat that scratched the first three tons of coal...

At the mine opening ceremony, Mr. X, in the time-honoured tradition, threw a cat into the shaft. It was the cat that scraped up the first three tons of coal.

to scrape: царапать, и еще:
[ trans. ] just manage to achieve; accomplish with great effort or difficulty : for some years he scraped a living as a tutor.
• ( scrape something together/up) collect or accumulate something with difficulty : they could hardly scrape up enough money for one ticket, let alone two.