The mine is now explored only by the most experienced cavers and members of the Royal Forest of Dean Caving Club (RFoDCC). Entry is through a gated depression on the edge of woodland near a large scowle hole. A steep and complex descent leads to the Second Level and the water table. From here, a southern route descends out of Echo Churn (now blocked), while a northern route leads through Boulder Chamber and up to the First Level via a rope-assisted climb.
The First Level runs almost to the infilled Old Pit, with further connections dropping back down to the Second Level. Notable features include the Honey Comb Rift with striking geological formations and a huge churn of ore near the site of a major surface collapse in 1913.
The mine has some of the most physically demanding conditions in the Forest, with steep muddy passages and unstable workings. There is no access via the vertical shafts; cavers may abseil into the capped Westbury Brook Shaft, descending 400 feet to the flooded levels and prussiking back up.

Trotter notes:

the mines as being, abandoned 1893 and flooded. The 4 levels are described and the total output during 1843 to 1893 being 958,000 tons

1864-1890 Dowlais Iron Co.

Westbury Brook Iron Mine was opened in 1837 by the Dowlais Company and operated until its closure in 1893, during which time it produced approximately 958,000 tons of iron ore. The mine was developed on four main levels. Levels 1 and 2 were accessed via the 360-foot-deep Old Shaft, while Levels 3 and 4 were driven from the later Westbury Brook Shaft, which reached a depth of 670 feet. The lower levels lie below the water table and are now permanently flooded.
Level 3 was reputed to have reached into the St Annals workings and, through them, the Shakemantle complex, creating a possible underground link extending five and a half miles southward to the Perseverance Iron Mine.
The Old Shaft was backfilled during the 1960s, and the Westbury Brook Shaft was capped with concrete, though it remains visible and has an access hatch used by experienced cavers.

The entrance used today is near a prominent scowle hole at grid reference SO 66260 16505, located on the high ground above the A4136 just below the Owl’s Nest car park. From the car park, a rough track leads uphill to a junction at a sharp bend—park here without blocking access, then walk down the forestry track and take a right turn 50 yards past the barrier. The gated entrance lies in a depression just 30 yards further along the path.