The Barqueiros mine, SA-Mibal, was opened in 1965 with the purpose of exploiting the mineral deposits of kaolin - a white sedimentary mineral used to manufacture ceramics and paints – located on a farm far from the center of the parish. Serious divergences between the company and local residents soon began to emerge, however, as their wells dried up and due to the lack of maintenance of the craters opened up by the mine.
In 1987, Mibal obtained the concession for a second kaolin mine, this time located in the center of Barqueiros parish. This sparked the conflict that became known as the "War of Kaolin": the day the company prepared to start operating the new mine, the population took to the streets in protest and stopped the operations from beginning.
In 1989, Mibal insisted once again on initiating operations at the new mine. The population went back out on the streets. However, police repression led to the death of a twenty-year-old man. Again, operations did not start and the company received economic compensation from the government for its loss and had to wait until the "objective conditions" were in place to begin operating.
In 2000, the company applied for a permit to exploit 100 acres in the town of Vila Seca, also in the municipality of Barcelos. The population held demonstrations on the streets and threatened to revive the "War of Kaolin." About 200 Vila Seca residents declared their opposition to the exploitation of kaolin during a municipal assembly. The municipality of Barcelos rejected Mibal's request.
More than seven years later, in 2007, Mibal obtained official authorization to operate in part of the area in Vila Seca. The municipality of Barcelos approved a motion to cancel the concession and, after several unsuccessful attempts to negotiate and reach agreements, it announced the filing of a request with the Administrative and Tax Court of Braga for an injunction against the permit, arguing that it violated the municipal master plan.
In 2009, Mibal started exploiting kaolin in Barqueiros with the approval of the municipality of Barcelos (following a change in municipal administration from the Social Democratic Party to the Socialist Party). The Civic Movement of Barqueiros launched a petition against this decision.
In early 2010, another protest was held in front of the Barcelos city hall to contest kaolin mining in Milhazes and Vila Seca. Mibal demanded that the municipality of Barcelos pay it 11 million euros in compensation due to the impediments to its mining activities. It declared that it was willing to give up lawsuits if the municipal council allowed excavations in Vila Seca. In September 2011, the exploration of kaolin began thanks to an agreement between the Barcelos city council and these parishes.
In 2014, the local newspaper, Barcelos Popular, called the conflict over kaolin "an endless controversy". It pointed out that Mibal has not fulfilled the terms of the protocol it signed with the local parishes, the DGEE, and the municipality.
In the central region of Portugal, there are several cases where company requests to exploit kaolin mines have caused protests. In the Cantanhede parish, one request involves an area of over 2,300 hectares, which is where the protection zone for the source of Olhos de Fervença is located. Olhos de Fervença supplies drinking water to over 60,000 residents in the area.
In Figueira da Foz, in 2014, a company filed a request for a permit to mine kaolin. The region has a vast forest area and is close to waterways and lakes. There is also a considerable amount of farming in the area. The residents launched the "Pela Vida, Contra o Caulino" (“Yes to Life, No to Kaolin”) movement and organized protests against the mining project together with political parties and the municipalities.
In the Pombal parish in the Leiria district and the Soure parish in the Coimbra district, an application was submitted to obtain the license to open a mine in an area with several towns nearby. The “Comissão de Luta Contra a Exploração de Caulinos” (The Fight against Kaolin Mining Mobilizing Committee) was created, which held protests together with other associations.