Bukkit

Mineral Vein changes the way ores are generated. Instead of lots of small, randomly placed deposits, several huge veins will be generated.
Source

MC 1.2.3 - As of MV 1.4.1, config.yml is used instead of veins.yml. The format renames the same, only name changes

Technically, Mineral Vein adds new BlockPopulator that removes all previously placed ores and generates new ones. This ensures compatibility with any other world generators, including the default one.

Veins

Veins are vast, rare areas, that are rich on particular resource. These veins are multiple chunks wide and long, their respective resources don't exist outside them. Veins aren't made completely of given material, it's just very common there, and often multiple veins of different materials overlap. This ore distribution changes mining for resources completely - you have to scout wide areas for a vein, and when you finally find one, it can supply you for quite a long time. In general, the average density of resources/chunk is simillar, but the distribution is changed completely.

Converting old worlds

By default, the plugin works as world generator and only affects newly generated chunks. However, you can force it manually to apply the algorithm to any chunks that are already present.

The command \mineralvein apply <worldname> [x] [z] [width] [height] will apply this to the selected world. Run this command just once after installing MineralVein, then you don't have to run it at all. By default the command is accessible from console and/or anyone with "MineralVein.apply" permission. (since you need to run this command exactly once, you propably won't need the permission at all.

The numbers default to 0,0 (center) and 200x200 chunks around it. If your map is bigger, use appropriate setting (widht corresponds to X coordinate, the value is in chunks).

Configuration

All variables used in ore placement can be set in config file.

worlds:
  default:
    -
        block: GOLD_ORE
        seed: 35434
        density: 3
        thickness: 4
        densityBonus: 0
        heightAvg: 20
        heightVar: 20
        heightLength: 80
        densLength: 80
        exclusive: false
        #biomes: [forest,swampland]
        #exclude_biomes: [desert]
        mode: replace
        heightRel: false

Each item of the list represents one "layer" that is generated. By default, there is one layer for each ore type, but there can be more.
seed is a unique number for each layer. If you want to create a layer with two different ores, that always uses same space, just use the same seed.

density is a chance multiplier. Higher density means more ore
thickness is vertical size (actually it's distance from the center of the vein, in which the ore can spawn, so it's one-half of the actual thickness)
densityBonus -the density in an area is determined using a random generator, that gives values between -1 and 1, where 0 and less represent no chance of ore spawning in given location. Giving a densityBonus of 1 will represent in this layer to be filled with resource everywhere on the map.
heighAvg is the average height in which this layer can be found
heightVar is the random portion of heigh, the actual heigh goes from avg - var to avg + var (in the example, setting of 20/20 would result in layer beeing between 0-40)
heightLength is distance in blocks between height definition points changes (higher values -> less frequent height changes)
densLength is distance in blocks between density definition points changes (higher values -> bigger, rarer veins)
exclusive parameter makes sure no other veins appear if this one is present (technically, it descreases their chance by the density of this ore here)
biomes is a list of biomes this vein can appear in. If this parameter is NOT present, it appears everywhere.
exclude_biomes is a list of biomes to be excluded from the list (logically this should be used when biomes option is defaulted to all)
mode allows to turn off replacement (by setting mode to "add") - this vein will just add more blocks, without removing the old ones
heightRel changes the behavior of heightAvg and heightVar. If set to true, those two will be treated as fractions of maxHeight at current position (heightAvg+-heightRel will result in a number between 0 and 1, which will be then multiplied by actual height of terrain on that position)

Changelog:
Version 1.3.7:

• Now supports ANY id, even non-existing ones. Useful for MCForge-added blocks (e.g. Industrialcraft)
  
  • Version 1.3.4:
    

• Two new config options - mode and exclude_biomes
  
• Fixed bug with using same noise generator for height and density
  
• Fixed apply command
  

Version 1.3.3:

• Fixed crash for config files that don't have "default" world setting
  

Version 1.3.2:

• The "Apply" command is now executed in separate thread, and worlds can be referenced by their index (failed command will display list of worlds and indexes)
  
• Huge changes in default config file, hopefully for the best
  

Version 1.3.1:

• The "Apply" command now works much better and safer
  

Version 1.3:

• Added exclusive and biomes parameters to config
  
• It is now possible to populate already existing worlds
  

Version 1.2:

• Added heightLenght and densLength parameters to conf file
  

Version 1.1:

• Fixed bugs, switched to in-built Noise generators for better results
  

Version 1.0:

• First release