As will subsequently appear, the history of the workings in the Brockwell Seam is of cardinal importance in its bearing upon the disaster, and it is accordingly summarised here. From 1821 to 1848, when the Benwell Royalty was still undivided, the Brockwell Seam was worked by a Mr. Matthew Liddell from a shaft situated in what is now the leasehold of William Cochran Carr, Limited, and variously known as the Paradise Beaumont or West Benwell Pit, distant about a mile and a quarter to the east in a straight line from the View Pit. These workings extended on both sides of the boundary line now dividing the two present leaseholds. They were abandoned in 1848 on the coal becoming unsaleable for household use, and subsequently became filled with water. Without going into the details of certain transactions in 1876 and 1877, it is enough to say that the present division of the mineral field first came into existence in 1881. As from 1st July of that year, under a lease dated 31st December, 1883, Thomas Walter Benson,

William Robert Benson and Walter John Benson, all since deceased, the predecessors of William Benson and Son, Limited, became the mineral lessees of an area of 750 acres, including the Brockwell Seam, to the west of a boundary line then fixed on the surface and shown on the plan annexed to the lease. Under a lease dated 23rd October, 1884, the late William Cochran Carr, who had previously had certain interests in the Benwell minerals, became the lessee of the minerals, including the Brockwell Seam, in the area to the east of the same boundary line. Mr. William Cochran Carr was the predecessor of William Cochran Carr, Limited, the present lessees. The boundary line so fixed has since remained the dividing line between the two leaseholds. (See Plate II.) The leases make no reference to the old workings.

The old pre-1848 workings in the Brockwell Seam from the Paradise Pit were never re-opened or worked by Mr. William Cochran Carr or his successors in the eastern leasehold, known as the Benwell Colliery, and the Pit and workings remained waterlogged. The existence of these old workings was known to the lessees of the eastern leasehold and the area where they were situated was barred off by a line drawn on the working plan. The Brockwell Seam was, however, from 1895 onwards worked in another part of the eastern leasehold from the Charlotte Pit, which is situated some distance to the north of the Paradise Pit.

The tenants in the western leasehold known as the Montagu Colliery from 1884 onwards worked continuously and extensively in the Brockwell Seam from the View Pit. At the time of the accident their workings in that seam to the east had approached to within 94 yards of the western boundary of their neighbours' leasehold. As they were required to leave a barrier of 40 yards on their side of the boundary they had therefore about 54 yards ahead still to work.

On Plate III the pre-1848 workings in the Brockwell Seam from the old Paradise Pit are shown in their relation to the boundary subsequently fixed in 1881 and it will be observed that this boundary for a part of its length passes through the most westerly portion of these old workings in the Brockwell Seam, thus causing a part of them to be in the present eastern leasehold and a part of them to be in the present western leasehold. This is a crucial fact in the case.