There are many other ethnic groups migrating from other province of Indonesia, such as the Batak Mandailing people who mostly lives in areas bordering North Sumatra such as Rokan Hulu. Most of the Mandailing people now identify themselves as Malay rather than as Minangkabau or Batak. In the 19th century, the Banjarese of South Kalimantan and the Bugis of South Sulawesi also began arriving in Riau to seek better lives. Most of them settled in the Indragiri Hilir areas, especially around Tembilahan. The opening of Caltex oil mining company in the 1940s in Rumbai, encouraged people from throughout the country to migrate to Riau.