He added that he wished that he had done more as an executive at the platinum producer Lonmin to improve them.
His comments to an inquiry into the police slaying of 34 striking [DATA LON:Lonmin Plc] miners two years ago were the latest sign of political pressure on mining companies to implement social obligations required by the government but poorly observed.
"Living conditions that workers were exposed to is not something I can proudly say I can be associated with. In fact, they are appalling and inhumane," Ramaphosa, a former mining trade unionist turned tycoon, said in his second day of testimony.
(WATCH VIDEO: None ignorable Marikana's economic landscape effect)
Ramaphosa, seen as the likely eventual successor to President Jacob Zuma, was a non-executive director at Lonmin when negotiations to halt a violent wildcat strike at its Marikana platinum mine west of Johannesburg ended in police shooting 34 strikers dead on Aug. 16, 2012.
As well as investigating the shootings, the commission of inquiry has a remit to look into labour relations, pay and accommodation in South Africa's mines - issues seen as spurring the strike that preceded the killings.
Ramaphosa highlighted the company practice of paying miners a "living out allowance" as one area of concern.
Miners, mostly rural migrants, often use that cash to rent hovels instead of proper housing because their wives and children are maintaining a plot in their home village while the miners also supporting a mistress and children near the mine. As a result, overcrowded shanty towns lacking basic services have sprung up around the mines.
"I should also have looked more closely at the unintended consequences that flowed from paying workers a living out allowance and finally getting to a point where they took the money and went to live in less than desirable accommodation," Ramaphosa said.
Mining companies in South Africa are supposed to comply with a number of social and labour regulations, including providing proper housing, to help a mostly black labour force that was exploited and ill-treated under apartheid.
(WATCH VIDEO: South Africa remembers the bloodiest post-apartheid labour incident in Marikana)
Bullion producer Gold Fields said this week it had received a letter from the government expressing concern about its social and labour plans, but did not think the licence of its flagship South Deep mine was in jeopardy.
Ramaphosa is the most prominent witness called by the probe into the Marikana killings, which began in October 2012.
The killings, the deadliest incident involving security forces since the end of apartheid in 1994, have become known as the "Marikana massacre".
Ramaphosa has been accused of putting political pressure on the police to use force against striking miners before the shooting, and was confronted at Monday's hearing by more than a dozen people chanting: "Blood on his hands!" He told the inquiry his intervention had been intended to prevent loss of life.