I'm going to test your script after school, I just made a quick look (sorry), some suggestions :
1-Why not make a premade colour ? It would make it more user-friendly. If you can, add a form for make it really more user-friendly to people that know nothing about the scar scripting.
SCAR Code:
const
// ***************** Colors taken in Very Bright Mode *********************
Clay = 4885165;
Copper = 4351888;
Tin = 8684172;
Iron = 2371664;
Silver = 10856117;
Gold = 3775149;
Coal = 2834753;
Mithril = 7359564;
Adamant = 6322272;
// ************************************************************************
rockcolor = Copper; // What kind of ore do you want to mine ?
2-Don't forget to use randomwait to make the script less detectable :
You can also make a rockwait constant, in this, the player can fill the rockwait himself, it would make it more adapted to the player.
3-Also, you can add findtalk; and findpick; in random verifications
. If you add findtalk (two or three times). You'll need to declare the following bitmap and the constant Nickname. Findtalk will check for randoms that talk to him.
SCAR Code:
const Nickname = 'wnu' // Type 3-4 letters of your runescape username
NickNameBmp:=CreateBitmapMaskFromText(Nickname,UpChars);
For findpick, it find your head pick if lost. You need to add FindPickHeadColor; at your script. You can make that if the script don't find the head color, it terminate the script.
SCAR Code:
if not FindPickHeadColor then exit;
4-Just look at the other script for some ideas, check the SRL include, check the tutorials etc... I'm also a newbie so I think i can't tell you too much things like that because I need me also to learn alot 
It a nice start, hope to see nexts versions of your script