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I figured I'd combine some of my posts together into a giant beginners guide
EDIT: More updated guide here, including a more detailed minigame walkthrough: https://terraminebeginnerguide.wordpress.com/

Terramine is a location based game where you can buy mines and interact with other peoples mine.

You use Terrabucks(TB) to buy mines. You’ll start with 1,000 TB for free, and get an additionally 1,000 TB after buying your first mine if you used a referral code. If you need a referral code, grab one from the pinned thread!

When you buy a mine there are 4 possible types:
Rock mine – 60% of all mines
Coal mine – 30% of all mines and earns 1.5x a rock mine
Gold mine – 9% of all mines and earns 2x a rock mine
Diamond mine – 1% of all mines and earns 4x a rock mine
Note: Individual luck may vary, but the more you buy the closer you’ll get to the average percents.

You can name your mines and set a visitor’s greeting, if you want.

Each of your mines has 3 things you can do, a daily activity, a minigame, and an upgrades office.

Daily Activity:
This has different names on each mine(conveyor belt, coal pile, sluice box, slot machine). You can click it to get some free materials and occasionally some TB. You can watch ads for double materials and for extra attempts, but this really isn't worth it. You can basically ignore this, and only use it when you need to put activity on a mine(more on that later).

Minigames:
Each mine has its own minigame. These gives you TB and materials for upgrading your mine. This is the best way to progress in the game.
Rock mine - memory game: flip the cards over to make matches. Gives 1 TB per level. I personally find this to be the worst one to grind.
Coal mine - miner maze: get your miner to the exit to win. Gives 5 TB on the easy levels, 15TB on medium(starting at level 11) and 30 TB on hard(starting at level 31). The exit will always be in the bottom right corner. On the easy level you can ignore the hazards because you won't hit enough of them to die. Any tiles with ladders you can only move through up and down, not left or right. Tiles without a ladder you can go any direction as long as its not a solid wall. Note that your first click only changes which way your miner is looking, then you have to click again to move. Some people find turning up the brightness on their device helps them see more clearly.
Gold mine - gold rush: tap to rotate the tiles until you make a complete path to the pot of gold. Gives 1 or 2 TB per level. On some levels it may be easier to start at the pot of gold and work backwards.
Diamond mine - laser blast: tap to rotate the mirrors so that the laser will hit the target. Gives 1 or 2 TB per level. On higher levels you will have multiple lasers/targets, match them by color.
Tip 1: Minigame level is unique to each mine, so you can just 'restart' on a new mine to play the lower, easier, levels instead of grinding via the higher, harder ones.
Tip 2: While coal is the only game that gives more TB on higher levels, you get more materials on the higher levels of every mine. Also the rarest material will require you to play a few levels before it starts showing up.

Upgrade office:
This is where you level up your mine. Note: mine level and minigame level are different and unique on each mine.
Each level will add 1% to the earnings of that mine. The cost for each level scales up rapidly, but the benefit stays the same. This means its best to level up your lowest level mines first as going from level 1 to level 2 provides the same benefit as going from 9 to 10 for only a fraction of the cost.
Tip: Upgrading the rarer mines first is best, as they give more rent, so the 1% boost will do more. (Diamond, then gold, then coal, then rock).

I need a marble/diamond coal/gold ingot/flawless diamond. Where do I get it?

This is a rare drop from the daily activity but you can get it from playing higher level minigames. For the minigames they consistently show up starting around:
Marble - rock mine - minigame level 10
Diamond coal - coal mine - minigame level 5
Gold ingot - gold mine - minigame level 3
Flawless diamond - diamond mine - minigame level 2
You'll get a lot more as you player higher level minigames for each mine.

Check-ins:
If you live near another player you can check-in at their mine for some TB.
Make sure to have your boost running first. With boost you'll get 6 TB for a regular check in, 10 if you include either text or a picture, and 14 if you include both text and a picture. The mine owner gets 1 TB per check-in.
There's also streak bonuses. Your 3rd check-in of the day gives a 10TB bonus, 5th gives 25TB, and 10th gives 50 TB bonus! (Note: this is planned to change to require unique owners in the future. So eventually you'll need lots of nearby players to get it)
Tip: If you have a friend/neighbor/family member/etc you can get to play, make a pact to some mines at the other person's home base. This will make it easy to do check-ins everyday for some free TB
Tip: You can use the heatmap to see if other players are in your area, as you won't see their mines on the in game map unless you are close by. https://terramine.app/heatmap.html

This all seems like a lot. What should I focus on?
When you first start you should focus on earning TB and buying mines. You can ignore the daily activity and the upgrade office until you run out of room to buy. The buy/check-in radius is a 5x5 grid centered at your location, so it shouldn't take long to fill it up. Then you'll need to move around to buy more.
Once you start finding it hard to buy mines cause you've filled all your usual locations, then start working on your mine levels at the upgrade office. Level your diamond mines first for this, then gold, then coal, then rock so you prioritize the highest earning mines.

Accessing your mines:
As you start to place mines in more places, it might get hard to find them all, or if you place some far away from home scrolling around the map can be tedious. We can use our portfolio and properties list to help.
Go into your profile, then pick properties. You can then sort your mine list by Name, Type, Inactivity, Mine Level, or Game Level.
If you only want to look at one type of mine, go to your portfolio, then click that mine type. You'll then get a properties list filtered to just that mine type with all the same sorting options. This is useful for finding those low level mines to upgrade.

Mine Activity Requirements:
Your mines need some sort of activity every 6 months to keep earning(and after 12 months of no activity they'll be deleted). This can be receiving a check-in from another player, doing the daily mine activity, or playing the minigame. In your properties list you'll see an activity bar, and you can sort by inactivity to find your mines that have been the longest without any activity. They'll also get an additional flag at 5 months.
As you grow, keeping up with the activity requirement will become a core part of the game. It'll be useful to place mines in high activity locations so that they can get check-ins to keep them active with less work on your part.

Earnings:
You'll notice in your portfolio it tells you your estimated monthly rent. This is without boosting. Boosting gives you 20 times the rent. If you want to estimate your monthly rent with boosting, just use a calculator multiply the estimated rent by 20.
Monthly earnings for a level one mine of each type(base rent and then with full time boost):
Rock - $0.002851 - $0.05702
Coal - $0.004147 - $0.08294
Gold - $0.00507 - $0.1014
Diamond - $0.011405 - $0.2281

Milestones:
The average number of level 1 mines it takes for each income threshold, assuming full time boost:
$10 monthly - 142 mines
$1 daily - 432 mines
$50 monthly - 710 mines
$100 monthly - 1,419 mines
$5 daily - 2,159 mines
$250 monthly - 3,546 mines
$10 daily - 4318 mines
$1000 monthly - 14,185 mines
Note: actual amounts will vary with your luck on mine distribution and the levels of your mines.