Bill Dalzell of Classical Numismatic Group writes:

IRELAND, Countermarked coinage. Kilkenny. Castle Comer Colliery. AR Dollar (41mm, 26.63 g). Countermarked circa 1804-1806 by Anne, Countess of Ormonde. PAYABLE · AT · CASTLE · COMER · COLLIERY · around 5s,,5d within a tuliped oval border; all within serrated oval cartouche on a 1796 Mo FM 8 Real of Carlos IV of Spain. W.A.. Seaby, in BNJ 34 (1965), pl. XV, 3 (this coin); Manville 108 (this coin cited); KM 145. Host coin Fine, countermark VF, toned. Very rare.

To read the complete lot description, see:
Very Rare Castle Comer Colliery Countermarked Dollar(https://cngcoins.com/Coin.aspx?CoinID=273783)

The Spanish dollar or 'piece of eight' reales counter-struck '5 shillings & 5 pence' for use in trading by the Castle Comer Colliery, in Co Kilkenny, is the only silver crown-sized piece issued in Ireland by a private commercial entity. They were produced on behalf of Anne, Duchess of Ormonde - the wife of the seventeenth Earl of Ormonde, John Butler. Her real name was Susan Frances Elizabeth, daughter and heiress of the Earl Wandesford. She married John Butler in February 1769 and survived her husband, her son, and her daughter-in-law, before she herself died in Dublin in April 1830. She was known as Anne and she was the Dowager Countess described by Mr. J. G. Robertson of Kilkenny to his friend, Dr Aquilla Smith in his article of 1855.

It was said, at the time, that she ...

These tokens are interesting insofar as most of the previous tokens were issued to make up for the lack of small change, e.g. the 17th C Tradesmens' Tokens. These tokens belong to an era of a shortage of specie (silver and gold) - a time when the Royal Mint was unable to acquire sufficiently large amounts of bulk silver to mint sufficient coinage for the British economy - an economy that was struggling to implement the recently passed Act of Union. Trade and commerce were being strangled by the inability to transact business.

To read the complete article, see:
O'Brien Rare Coin Review: The Castlecomer Colliery Tokens(https://oldcurrencyexchange.com/2015/06/08/obrien-coin-guide-the-castlecomer-colliery-tokens/)

Eric Hodge writes:

To read the complete article, see:
GASTLEGOMER TOKENS: AN INOUIRY(https://www.britnumsoc.org/publications/Digital%20BNJ/pdfs/1965_BNJ_34_21.pdf)
THE CASTLE COMER COLLIERY TOKEN(https://www.britnumsoc.org/publications/Digital%20BNJ/pdfs/1962_BNJ_31_18.pdf)
Lot 614 IRISH COINS, Tokens, Co KILKENNY, Castlecomer, a plated counterfeit MEXICO, Charles IIII, 8 Réales(https://www.numisbids.com/n.php?p=lot&sid=1888&lot=614)
Castlecomer Colliery Tokens c.1800(https://www.facebook.com/media/set/?set=a.953967818011390.1073741839.476470342427809&type=3)
Ireland, Co. Kilkenny, Castlecomer Crown(https://web.archive.org/web/20160414214442/http://www.irishcoins.com/?id=5398)

To read the earlier E-Sylum article, see:
NOTES FROM E-SYLUM READERS: JANUARY 16, 2022 : Query: 8 Reales Countermarked for Castlecomer Image Sought(https://www.coinbooks.org/v25/esylum_v25n03a17.html)