Butterley Company minimum rent account book for the Langley Collieries District Recording in heading name of party to lease, with date of lease, term of years and expiry year (earliest lease going back to 1851). Columns for date of half year ending, name of seam, area worked, royalty rent, amount of rent, surplus for half year, deficiency for half year, and total overpaid. Index pages at front Mar 1891-Dec 1946