Mining

Overview
Anyone can create a user interface for mining a CityCoin, two examples being minecitycoins.com and syvitamining.com.
Mining CityCoins happens by calling one of two functions in the contract: mine-tokens and mine-many.
Miners can only participate once per block. Once STX are sent for mining a CityCoin they are not returned, they are distributed to the city's wallet and CityCoin Stackers.
A nominal transaction fee is required in order to send this transaction, paid in STX, and in a single mining transaction you can optionally include a memo that will be recorded on-chain.
Details
To mine for a single block with mine-tokens:
enter the amount you would like to bid for the block
(optionally) enter a memo to be recorded on chain
submit the transaction to the smart contract
To mine for multiple blocks with mine-many:
select the number of blocks you would like to mine for
enter the amount for each of the number of blocks selected
submit the transaction to the smart contract
Contract Functions
​API Ref: Mining​
get-mining-stats-at-block
Type: Read-only Function
Input: stacksHeight as uint
Returns: (some MiningStatsAtBlock) as a tuple or none
Returns the mining stats at a given block height, including:
minersCount -  total miners
amount -  total amount committed
amountToCity - amount transferred to city wallet
amountToStackers - amount transferred to $MIA Stackers
rewardClaimed - true/false if reward was claimed
get-mining-stats-at-block-or-default
Type: Read-only Function
Input: stacksHeight as uint
Returns: (some MiningStatsAtBlock) as a tuple, or defaults
Returns the same as get-mining-stats-at-block above, except if no entry is found, returns the default structure of:
minersCount: 0
amount: 0
amountToCity: 0
amountToStackers: 0
rewardClaimed: false
has-mined-at-block
Type: Read-only Function
Input: stacksHeight as uint and userId as uint
Returns: true or false
Returns a boolean value indicating if the user's ID mined at a given block height.
get-miner-at-block
Type: Read-only Function
Input: stacksHeight as uint and userId as uint
Returns: (some MinersAtBlock) as a tuple or (none)
Returns the mining stats for a given user ID and block height, including:
ustx - total commitment in uSTX
lowValue - used by VRF to determine winner
highValue - used by VRF to determine winner
winner - true/false updated after miner claims the reward
get-miner-at-block-or-default
Type: Read-only Function
Input: stacksHeight as uint and userId as uint
Returns: (some MinersAtBlock) as a tuple, or defaults
Returns the same as get-miner-at-block above, except if no entry is found, returns the default structure of:
ustx: 0
lowValue: 0
highValue: 0
winner: false
get-last-high-value-at-block
Type: Read-only Function
Input: stacksHeight as uint
Returns:highValue as uint, or default (u0)
Returns the last high value at a given block height, which is incremented with each miners' total commitment.
get-block-winner-id
Type: Read-only Function
Input: stacksHeight as uint
Returns:  (some userId) as uint or none
Returns the user ID of the block winner after the  miner claims the reward.
mine-tokens
Type: Public Function
Input: amountUstx as uint and memo as buff 34 (optional)
Success: (ok true)
Errors:
ERR_CONTRACT_NOT_ACTIVATED u1005
ERR_USER_ALREADY_MINED u1006
ERR_INSUFFICIENT_COMMITMENT u1007
ERR_INSUFFICIENT_BALANCE u1008
ERR_STACKING_NOT_AVAILABLE u1015
Mining for a single block happens through calling the mine-tokens function in the contract, which optionally accepts up to 34 characters as a memo to record on-chain.
mine-many
Type: Public Function
Input: amounts as list of uints, up to 200
Success: (ok true)
Errors:
ERR_CONTRACT_NOT_ACTIVATED u1005
ERR_USER_ALREADY_MINED u1006
ERR_INSUFFICIENT_COMMITMENT u1007
ERR_INSUFFICIENT_BALANCE u1008
ERR_STACKING_NOT_AVAILABLE u1015
Mining for many blocks happens through calling the mine-many function in the contract, which accepts a list of amounts up to 200 items in length.