Francis Oats (29 October 1848 – 1 September 1918) was a Cornish miner who became chairman of De Beers diamond company.

Francis Oats was born on 29 October 1848, at South Torfrey Farm, Golant, near Fowey, Cornwall, England, in the parish of St Sampson.

[1] Like most young men in the district Oats became a miner when he left school, but every week he would walk to Penzance, seven miles away, to attend evening classes so he could become a mining engineer.

[2] At the age of 17, Oats placed second in the mineralogy examination for the British Isles, and obtained a high grade in mining, a subject in which he had not been instructed.

[3] On 9 December 1874, Oats was appointed Cape Colony Government Mining Engineer at Kimberley, South Africa, at the age of 26.

[6] The colony's government had recently passed ordinances in favour of small miners which prevented mine concession owners from imposing excessive rentals on the diggers and shopkeepers, and did not allow an individual or company to hold more than ten claims.

[8] Oats, as Provincial Engineer, gave the decisive opinion that "fostering a large number of individual holdings is most adverse to economy of working.

[12] The De Beers directors were unwilling to buy the mine, but were reluctantly persuaded after Oats had investigated it and described the damage it could do to diamond prices.

He also forced adoption of water hydrants to lay the dust created by mining drills, the main cause of silicosis.

Oats demanded repeats of the experiment, and remained sceptical of some trick, saying the diamonds were too close in colour and shape to those of the Jagersfontein Mine near Kimberley.

Africa where a discovery has been made of some superficial deposits of diamonds, but fortunately for our prices, these, singularly enough, are all small in size.

"[20] Oats was making a serious error in discounting the German discovery, which had large and high quality diamonds, and dismissing Ernest Oppenheimer's Premier Mine, which was producing more than the total output of De Beers.

Francis Oats said the 1,000 men employed at the mines would be given half pay until the end of January 1915, when the company would decide what to do next.

There have been differences of opinion among the Directors but in the end we came to the conclusion that while this state of things lasted we must as far as possible confine ourselves to marking time, and not further increase the stock of unsold diamonds already on hand.

[21] Francis Oats died on 1 September 1918, in Port Elizabeth, Eastern Cape, South Africa.

[6] He tried to modernise the tin mine at St Just by sinking a new vertical shaft so that ore could be raised direct from the lower levels to the surface, a project that seemed even then to be uneconomical.

[24] Oats arranged for construction of Porthledden, a 21-bedroom mansion in Cape Cornwall designed as a gentleman's residence that was completed in 1909.