The Ashford Caves Karst Conservation Reserve contains an outcrop of coralline limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

. It is about 8 km west of the former Ashford coal mine, north of Ashford

Ashford, New South Wales

Ashford is a small farming community in the New England region of New South Wales, close to the Queensland border.-History:Frazer's Creek Post Office opened on 1 January 1853 and was renamed Ashford in 1863....

 and not far from the Queensland border town of Texas, Queensland

Texas, Queensland

Texas is a town in Queensland, Australia. The town is located just from Queensland's southern border with New South Wales, close to Bonshaw, New South Wales...

. Originally on a private property, the Ashford Limestone caves are now part of the Kwiambal National Park

Kwiambal National Park

Kwiambal is a national park in New South Wales, Australia located about 30 km from the town of Ashford. The Severn River and Macintyre River, both flow through and finally converge in the park below the MacIntyre falls. The park is studded with granite outcrops and also features the Ashford...

. A basic camping ground called 'Lemon Tree Flat' is nearby (within a 10 km Radius) as are the Macintyre Falls.

The large arch-shaped opening was made to access the phosphate

Phosphate

A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

 (guano

Guano

Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...

) resources for use as fertilizer

Fertilizer

Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

, which has been quite profitable. Prospects of mining limestone at this location have been explored, but dismissed as unviable.

A colony of Eastern Bentwing Bats a subspecies of the Common Bent-wing Bat inhabits the cave system and breeds from November through March.