Fig. 1

Layout of the 15,216 mining face showing dust sampling spots M₁–M₁₁ along the walkway side at a height of 1.5 m with mining and airflow directions indicated.
Layout of the 15,216 mining face showing dust sampling spots M₁–M₁₁ along the walkway side at a height of 1.5 m with mining and airflow directions indicated.