This is the 7937th most frequent Spanish word.
mineras
"Mineras" refers to "miners" (feminine) or things related to mining.
Here, 'mineras' is used as an adjective describing the type of companies that are involved in mining activities.
Las compañías mineras extraen minerales del suelo.
Mining companies extract minerals from the ground.
In this sentence, 'mineras' is used as an adjective qualifying 'actividades' to specify they are related to mining operations.
El impacto ambiental de las actividades mineras es significativo.
The environmental impact of mining activities is significant.
Here, 'mineras' is functioning as a noun, referring to 'mining companies' in a shorthand form.