Minera Quarry had two Hoffman kilns.

These replaced the earlier vertical draw kilns and allowed lime to be burnt in a continuous manner. Minera was quite forward thinking because this design was patented by German Friedrich Hoffmann for brickmaking in 1858. The first, built in 1868, had 24 chambers and a 225 foot chimney. The 2nd kiln was built in 1874 but was about half the size with just 12 chambers. Both kilns were used until 1954 when the company that took over operations no longer required them. The smaller kiln has disappeared, possibly buried during landscaping and alterations to the quarry. The larger kiln does remain but is half buried. The chimney is long gone but around half of the entrances can be seen. Each chamber had its own entrance. These are now blocked to prevent access because of bat roosts.