As far back as 1772 it was documented that Freemen were searching for coal on the Llantrisant Common.

A Court Leet presentment states that “Edmund Treharne and others were opening coalpits on the Commons, and committing trespass.

"There is a place on the Commons known at present as Pyllau Gloyon which no doubt is the spot where they were exploring for coal at that time.”

However, it was in November 1865 that the great commotion took place between the body of Freemen by the action of Lord Bute through his Trustee having given permission to T. Powell Esq to search for coal under the Common Lands.

The Freemen, who at this point amounted to 433, were led to believe they had a perfect right of the minerals below the Common.

The Cardiff Times stated in November 1865: “The Marquis of Bute is lord of the manor, and it is alleged that he has within the last few months given permission for two railroads to be constructed across portions of the Common and also sunk a coal pit, both of which are detrimental to the privileges and rights of the burgesses, who maintain that Lord Bute has no right to so act without their permission. It is also alleged that Lord Bute had granted a portion of the Common the parish clergyman for the purpose of building schools.”

Some fifty years earlier the agents of the Lord tried to establish a plantation on the land but were successfully stopped by the Freemen. 

Suddenly they were surprised to find a body of men sinking a shaft to explore the coalfield. The Llantwit Main Coal Company also began sinking two large pits on Llwyncrwn premises near to Powell’s works on Llantrisant Common. Some agreed with the decision, hoping it would bring prosperity to the area.

Many Freemen were infuriated by the intrusion. Meetings were held and subscriptions opened to defend their rights which was taken by Messrs C & F James, Solicitors, Merthyr Tydfil.

In October 1865 a preliminary meeting of the officers and members of the corporation was held at the New Inn, to consider what steps should be taken "in consequence of the Trustees of the Lord of the Borough having encroached on the rights of the Freemen, in causing pits to be sunk on part of their land called, and having constructed railways, buildings, and other trespasses.” 

The coal found on the Common would be sent over the railway to Cardiff. Packed public meetings were held by Portreeve Josiah Lewis to consider what steps should be taken. The meetings at the Guildhall included Dr David Lloyd of Aberpengwm and Judge Gwilym Williams of Miskin along with several influential people of the area and Freemen of Llantrisant residing elsewhere.

Charles H James, solicitor also addressed the meeting and resolutions were made by all present to fight the case until they were victorious.

David Morgan moved the first resolution:-"That the Trustees of Lord Bute have taken, in our opinion, the liberty of letting the mines under the Llantrisant Common, and granting the power of breaking up the surface by sinking pits, depositing rubbish, and constructing railways,to the injury of the burgesses of Llantrisant, without obtaining permission of the Court. the Portreeve, or the Burgesses.”

Thomas Lewis seconded the motion, which was carried unanimously, as were all the others. 

Mr Lloyd, of Aberpergwm, the ex-portreeve, addressed the meeting, and said he considered the question was a very large and important one, and “he thought, further than they could see at present, for they had not only to defend their common rights to the Common of Llantrisant, but there was a much larger question, what were their rights? It was true that for many years they had exercised the common rights of the borough of Llantrisant, but what were the corporeal rights? In order to defend those rights which had never been disputed, they had to fight against a powerful opponent, and they would need to take off their jackets. Let them remember that they were not fighting for themselves, but for their children.”

The newspaper columns were filled with articles and letters from “The Game Black Cock” among others.

The officers of T. Powell’s coal company went ahead with fencing off several acres of the common, causing even further annoyance with the arrival of engines and equipment to excavate more of the common land. Several buildings were  erected on the site but fortunately bad weather halted much of the work.

In February 1866 a general meeting was called when around 400 Freemen attended.  Many workers came to the area and around 12 new houses were being built in the town with many more planned as a consequence of the colliery.

The Freemen believed that the Borough of Llantrisant was outside the jurisdiction of the Manor of Miskin. They also demanded that the Lord compensated them for any damages caused to their surface rights when searching for the minerals.

Mr Charles James said they would need to raise £500 to begin with, adding. “If, therefore, the freemen of Llantrisant had right on their side, they need not fear Lord Bute or any other great man when they met him before the law.”

On 7 June 1866 an action of ejectment commenced in the name of the Portreeve and Burgesses against T. Powell Esq to recover possession of the land. The Trustees of Lord Bute a, took action in the Supreme Court to restrain the Portreeve and Burgesses from prosecuting them.

In May 1866 the committee met and it was revealed that many of the Freemen had not come forward to assist with the financial expense of the action. Many simply could not afford it. A newspaper report of August 1866 stated: “On Monday ten trucks loaded with coal were taken for the first time from the new colliery on the Llantrisant Common”. But a few days later and an accident occurred which caused the death of 57-year-old David Francis.

In April 1867 a news report read: “We wish to inform those who may still feel some interest in the suit which still drags its slow length along, that the sudden withdrawal of the notice of trial for the Swansea assizes did not arise from the Vice-Chancellor's discovery of either a latent or an ostentatious defect in the cause, but simply from a want of funds”

The actions were not proceeded with and in time judgement was allowed to go by default against the Portreeve and Burgesses with costs. But nothing further was heard of.

It was agreed that the purchase of the Manorial Rights by Sir William Herbert in 1551 from Edward VI the various manorial rights, privileges and customs, had reverted to the Crown.

When Sir William Herbert – Lord Bute’s predecessor – had the grant and particulars of the Manors, there is no doubt that all manorial rights, including the minerals, was conveyed in that grant. 

The Colliery was not as productive as first expected and closed within a few short years.

The issue of opencast mining on the Common was raised a century later, but on this occasion the Llantrisant Town Trust were victorious in fighting to maintain and protect the land and its ancient rights.