Amajina & Sons Mineral Concern
Mistress Amajina, the proprietress of a tavern, founded the Concern during the Mad Mythril Rush some century and a half ago. At present, the company controls the main mines in Thanalan, and has grown large and wealthy enough to afford a standing force of sellswords known as the Stone Torches.
— In-game description
A company of no small prestige, Amajina & Sons Mineral Concern does much in the name of Ul'dah's mining industry. Their operations are great in number, from the many shafts under their control to their railway—a modern venture that began operations immediately following the Calamity. Ever seeking new veins of ore, the Concern has built a number of structures for the purpose of prospecting in the frontier. In so doing, they have continually invited upon themselves the wrath of the Amal'aa and other wrothful beasts. Thus, the Stone Torches were established to defend these assets.
— Encyclopedia Eorzia
Amajina & Sons Mineral Concern is one of the largest mining operations in all of Thanalan. Originally founded by a tavern proprietress Amajina and her regulars, the operation has become an expansive empire, with several operations running several shafts and railways. Fyrgeiss Loetkilbsyn is the current Chief Foreman.
Following the Seventh Umbral Calamity, Amajina & Sons built several structures to prospect in the frontier. Doing this has invited several attacks of the Amalj'aa, which in turn gave birth to the Stone Torches.
Due to the mineral wealth of the region, mining has long been a central pillar of Ul'dahn industry. The Mad Mythril Rush—sparked by the discovery of a rich vein of the light, yet durable ore—brought particular prosperity and joy to the city-state but a century and a half ago.
Yet the miners themselves did not share in this newfound wealth. Working under harsh conditions for a mere pittance, many found themselves living in desperate poverty thanks to questionably legal contracts of servitude drawn up by dishonorable foremen. Their dissatisfaction grew, and with time the men and women banded together against the mining concerns who exploited them so. The result was the Miners’ Guild, which has faithfully worked since to improve working conditions while providing an outlet for the time-honored passing down of the tricks of their trade. 
- Encyclopaedia Eorzea: Volume I, page 141