What does the six-pointed star on the armband of the mine rescue team mean?

Mine rescue officers and soldiers wear armbands, and the rank mark on the armbands is:

1 class 1 octagonal star and 4 small pentagrams;

Grade 2 1 octagonal star and 3 small pentagrams;

Level 3 1 octagonal star and 2 small pentagrams;

Level 4 1 octagon;

Level 5 1 six-pointed star and 4 small pentagrams;

Level 6 1 six-pointed star and three small pentagrams:

Level 7, 1 six-pointed star and 2 small pentagrams;

Grade 8, 1 hexagonal star;

Grade 9, 1 four-pointed star and four-pointed star;

10 class 1 four-pointed stars and three pentagrams;

1 1 class 1 four-pointed star and two pentagrams;

12 level 1 1 four-pointed star;

13 1 triangle star and three pentagrams;

14 1 triangle star and 2 pentagrams;