The government also announced a crackdown on "illegal gatherings".
"The aim of the raid was to disarm the mine workers to make sure that we do away with the elements of threats that are taking their toll in the area of Marikana," regional police spokesperson Thulani Ngubane said.
Ngubane said police retrieved weapons such as machetes and spears.
Seven more people were arrested at around noon in Marikana, bringing the total to 12 on Saturday, North West police said.
Ngubane said the number was expected to increase.
"Those arrested [so far] have been charged under the Illegal Gathering Act as well as for public violence…. They have been burning tyres in the area," said Ngubane.
Earlier, five people were arrested during a disarmament operation at the Karee Mine hostel.
About 500 police officers raided the hostels in the early morning hours. About 6 000 mine workers stay at the Karee hostels.
"[They] were arrested for dealing in dagga," said Ngubane.
Police seized pangas, knobkerries and other dangerous weapons during the raid.
Ngubane could not specify how many weapons had been seized but said there were "truckloads" of them.
Those arrested were likely to appear in court on Monday.
Another seven were arrested on Friday for contravening the Act at the nearby Aquarius Platinum mine.
Conflict in the mining sector
Earlier, police fired rubber bullets and sprayed teargas in a bid to disperse the mineworkers in Nkaneng informal settlement in Wonderkop.
Workers had gathered at the open veld next to the koppie, where 34 people were killed in a violent confrontation on August 16.
At a media briefing held at the Union Buildings in Pretoria on Friday morning, Justice Minister Jeff Radebe said that the future of the mining industry was at stake and promised swift action from law enforcement officials against those who gather illegally and threaten violence.
Conflict in the mining sector has been simmering since last year, when there were protests at Xstrata and Impala Platinum. Matters escalated at Lonmin in August and have since spread to several nearby mines.
"These acts of violence and intimidation clearly undermine government efforts of ensuring economic and security stability," said Radebe. "Government recognises that if the current situation continues unabated it will make it even harder to overcome our challenges of slow economic growth, high unemployment, poverty and inequality."
"All those who continue to engage in illegal activities are going to be dealt with very swiftly," he added. – Sapa and Reuters.