Arranged into fifteen groups: Group One, Brynkinalt Colliery Company records, Brynkinalt Collieries Relief Society records, Llay Main Collieries Ltd records, and Ruabon Coal and Coke Company; Group Two, Broughton and Plas Power Coal Co., and Bersham Colliery records; Group Three, colliery surface plans, printed maps of colliery districts, lead mine and quarry plans, and miscellaneous; Group Four, Brymbo Colliery plans; Group Five, Point of Ayr colliery; Group Six, Broughton and Plas Power Coal Co., Bersham Colliery records, Llay Main Colliery records, Ruabon Coal and Coke Company records, and North Wales Collieries records; Group Seven, Broughton and Plas Power Coal Co., and Bersham Colliery records; Group Eight, Llay Main Collieries Ltd records; Group Nine, North Wales Employers' Mutual Indemnity Co. Ltd records, and Llay Main Colliery Company records; Group Ten, W. Y. Craig & Sons accident report books, Ruabon Coal and Coke Company records, and North Wales Mutual Indemnity Co. register; Group Eleven, colliery records; Group Twelve, North Wales coalfield seams correlation chart and related material; Group Thirteen, miscellaneous records; Group Fourteen, Bersham Colliery photographs; and Group Fifteen, Point of Ayr Colliery records.