Most line types are self explanative and don't need any option. As you can guess, countour is used to draw contour lines, pit is used to draw pits, and so on.

Rock-border and rock-edge are used to draw block borders and block inner lines respectively.

Section is used to draw a line showing cross-section position. This line type is somewhat tricky. It will be explained extensively with cross-sections.

Slope is used to draw a contour line with a tick pointing slope's direction. This symbol needs to have “L-size” checkbox checked on “Line point control” panel.

Border is useful when you need to draw a closed line to define an area. In this case, you'll probably want it to be invisible. To do this, write in “options” textbox:

-subtype invisible

And this border will be invisible. This “invisible” subtype apply to most line types, not only borders. For more information about line types and options that apply, please see thbook.pdf. You'll find line types in pags 21, 22 and 23.