In a translated statement issued on Monday, the company said the pulp was 70% iron ore and 30% water and was non-hazardous.
It said as a precautionary measure, it had asked authorities to cut the water supply to residents of Santo Antônio do Grama and was providing trucks to ensure the water for the affected population.
Anglo said it had technical teams on the way to support local teams and authorities with emergency response actions.
In an update posted in the afternoon, it said it was working to determine the volume of the leaked material from the Minas-Rio pipeline and had stopped all activities in Conceição do Mato Dentro until the causes of the accident were clarified.
The translated statement said there were no victims and Anglo's priority was to ensure the measures to control and mitigate socio-environmental impacts.
The iron-ore rich state was also the site of the deadly Samarco dam failure in 2015 from the BHP (AU:BHP) and Vale SA (BZ:VALE3) joint venture operation, which remains in limbo as remediation and compensation programmes continue.
Anglo's Minas-Rio iron ore operation produced 16.8 million tonnes (wet basis) in 2017, 4% higher than the previous year as the operation continues to ramp up.
It lowered its Minas-Rio guidance for 2018 to 13-15Mt due to lower grades in the remaining Step 2 area and the delays to its Step 3 operational licence process, which it hoped to have in place by mid-2019.