Mining tips and misconceptions

[nickasummers]

The server is down, so I needed something to do. All information here is a combination of direct information from this thread: http://www.minecraftforum.net/viewtopic....35&t=28299, interpretation of information from said thread, and personal observation. This post will omit the boring details and try to give you a concise explanation of how things work.
Overview of how ore is placed
When a chunk is generated, the game first builds the surface, and fills stone underneath. Then, it sequentially adds air pockets (natural caverns), dirt, gravel, ore, adminium, and random lava and water sources. These are added in a specific order, and for most of them (specifically ore), there is an exact number of pockets per chunk. When something gets placed, it replaces NATURAL STONE in the area the generator decides to place it. after everything is placed, lava is replaces any block of air below a certain level. Because of the order of placement, if you find ore next to dirt, chances are the dirt that was already placed resulted in less ore being placed (because ore only replaces stone, and is placed after dirt). It is worth noting that in each chunk, there is only ONE cluster of diamond and TWO clusters of gold. The method of ore placement explains many common misconceptions about mining.
Common Misconceptions and their origins
Ore is more common near lava
Many people think that ore is more common near lava. There is nothing in the code that causes this to be so, but there are many reasons why it seems this way. First, you only find lava in caverns, and caverns have lots of exposed surfaces, so its easier to find ore. Second, most of the lava you find is at the bottom of the map, where there are more types of ore that can spawn. On average, you will find as much coal on layer 50 as you find on layer 10. All ores are, on average, distributed evenly in the layers you can find it in. At the bottom of the map, you can find coal, iron, diamond, redstone and gold. on the surface you can only find coal and iron. So it makes sense that you would find extra ore near the lava at the bottom of the map.
Ore is often found near other types of ore
While it is true that you can find more ore by digging around other ore, this only acutally applys to ore of the same type. Two pieces of coal could be diagnally adjacent, so digging the stone around the first coal could find you an extra coal. However, Iron, for instance, spawns at the same rate both near and far from coal. You might find both iron and coal touching (or, as I saw once, coal, iron, redstone and gold all touching), but it is totally random.
Mining in caves finds more ore than random mining
Caves have a larger surface area than a randomly mined path, so you will see more ore walking through it, and you will walk through it faster because you aren't mining a path in front of you, but when you find ore you will, on average, find slightly less ore. This is because the air in the cave is placed before the ore, and the ore only replaces stone. As a result, if you can see those diamonds on the wall, chances are the air in front of them suppressed at least one potential diamond.
Common Types of Mines
Strip mine
Strip mining is when you chose an area and dig out every single block in the area. Some people like strip mining because you get every single piece or ore in the area, without fail. The problem is that most of what you mine is stone. Strip mines take a lot of time and produce mostly worthless junk. If you do mine out an entire chunk, you should always find diamond, but you will only find one cluster for all that effort.
Spelunking
Spelunking is when you find a cave, search through it, and try to empty it of all exposed ore. This is extremely time efficient, but you will find a lot more coal and iron than anything else because it will be harder to get down deep underground, and any exposed area below the "lava level" will have lava when the chunk forms, so you effectively lose half of the space a diamond could spawn in. Spelunking is also dangerous, as you are practically guaranteed to run into mobs.
Chunk Mining
I'm not sure who came up with this term, but its quite and interesting idea. Chunk mining is when you run around looking for chunks that failed to load, and look for valuable ore on the walls (or, potentially, lava-filled caverns), and dig straight down the edge to the ore, and then pillar back out with the stone you mined on the way. This method is quick, and if you make sure to look for lava and caves before you dig, fairly safe, but it is likely that it will be fixed soon because it utilizes a glitch.
Branch mining
Branch mining is based on the same principal as strip mining - get all of the ore in an area- but it is far more time and pick efficient. In a branch mine, you don't mine out every single block, you just mine out the blocks needed to SEE every block. In some cases. you might even set it up to skip a few blocks because you know that ore generally comes in clusters, so you should find MOST of the ore, and the few you miss are more than made up for in saved time. There are many different patterns for branch mines, and if you are interested in the theory behind them you should visit the thread linked above.

If you have any questions, feel free to post them and I will see if I can answer them.

[Sponson]

Diamond spawns near the lowest dozen levels give or take a few. But lava lakes exist at level 10. Do lava lakes suppress the accreation of diamond blocks, so while chunks always have diamond in them, the diamond can simply just not exist due to being "replaced" by lava?

[Geoff]

look ma i coined a term

but good writeup

[nickasummers]

Diamond spawns near the lowest dozen levels give or take a few. But lava lakes exist at level 10. Do lava lakes suppress the accreation of diamond blocks, so while chunks always have diamond in them, the diamond can simply just not exist due to being "replaced" by lava?

Lava at the low levels fills in natural caves. If you took lava out of the generation the area would look just like a cave, and the hollow spots in caves suppress the diamonds, so yes, diamond can fail to exist for that reason. Also, i believe that the numbers for heights are, if the bottom layer is 0: 0-4 is bedrock, 1-10 is lava (but bedrock is placed first, and lava generally only appears in a natural cave), and 1-16 is diamond (actually 1-19, but its very rare in 17-19, and only exists there due to a quirk in how it decides the exact location of the ore). This means that, because of the danger of lava, the fact that you have to clear it out somehow, and the fact that it can suppress diamond anyway, I personally usually only search in 11-16 for diamond and assume that if the diamond is below that it isn't worth the effort.

As for lava lakes in the sense that notch recently added random lava lakes (some of which appear even on the surface), I assume that they, too, suppress ore such as diamond, but I am not positive of that.

[nickasummers]

Mining patterns and Advantages for them
Maximum time efficiency

This cross section is, out of all cross sections they have analyzed, the most efficient when it comes to ore found over time for a MULTIPLAYER MAP. Ore tends to form in larger clusters in multiplayer, and as a result this cross section will find ~95% of the ore even though many of the blocks are left unseen, because if you see any of the ore in a cluster, you can find all of it. Open spots are mined, Gold is "directly visible" and diamond is "indirectly visible". Natural stone is likely never to be seen, but very little ore should lie in that zone, so the time you save makes up for them.
Maximum space-efficiency

With this pattern, all ore is exposed, so you will always find 100% of the ore, and there is no overlap in visible blocks, so it is still highly efficient. the downside is the lack of a whole layer that is unmined making it a bit harder to plan out.
Easiest design

This pattern is very easy to organize and fairly effective, but some ore is only indirectly seen, and the unseen ore is not made up for in speed.

[PyroZombie]

A question, mining master;

I'm currently using the branch mining method, but its yielding nothing but steel. Should I move on ?

[demonspork]

Bump for Alleycat

[heavyrocker1989]

thanks, but i'm still going to keep mining my own way... which is beat up every block around.

[Luinbariel]

My branch mine is now literally infested with slimes.

[Versus]

nerd alert

[Kirby]

My branch mine is now literally infested with slimes.

I managed to drop my swarm into a lava pit by mining around the then herding them into it, but they still won't die.

They're just hopping around, boing'ing, on fire, in a pit of lava.

[Luinbariel]

It is more than one swarm. At the end of EVERY tunnel on the second last level of my mine there are at least five or six slimes. I built a pit with rilnac and we lured them all into it upstairs, including one huge slime. But they seem to disappear after I logout, at least most of them do, from the pit. The ones downstairs are still there though.

[at0m]

I had a similar problem in my ore garden. I lured them into a pit and lit them on fire with netherrack, then logged out. They all died.

[Dtrain323i]

I have yet to see a single slime.

Also if you create a world with a seed of "Strongbadia" you'll find buttloads of coal.

[at0m]

I have yet to see a single slime.

Also if you create a world with a seed of "Strongbadia" you'll find buttloads of coal.

I know where there are quite a few, but unless you have flymod you can't get to them. They occasionally spawn in my basement, but it's relatively rare.