diff --git a/api/src/state/config.rs b/api/src/state/config.rs
index 970a5d1..3dacec7 100644
--- a/api/src/state/config.rs
+++ b/api/src/state/config.rs
@@ -10,20 +10,20 @@ use super::AccountDiscriminator;
 #[repr(C)]
 #[derive(Clone, Copy, Debug, PartialEq, Pod, ShankAccount, Zeroable)]
 pub struct Config {
-    // TODO Remove this
-    pub admin: Pubkey,
-
     /// The base reward rate paid out for a hash of minimum difficulty.
     pub base_reward_rate: u64,
 
     /// The timestamp of the last reset.
     pub last_reset_at: i64,
 
-    /// The largest known stake balance on the network.
-    pub max_stake: u64,
+    /// The minimum accepted difficulty.
+    pub min_difficulty: u64,
 
     /// The address of the proof account with the highest stake balance.
     pub top_staker: Pubkey,
+
+    /// The largest known stake balance on the network.
+    pub top_staker_balance: u64,
 }
 
 impl Discriminator for Config {
diff --git a/program/src/crown.rs b/program/src/crown.rs
index e9a2463..41c2999 100644
--- a/program/src/crown.rs
+++ b/program/src/crown.rs
@@ -56,8 +56,8 @@ pub fn process_crown<'a, 'info>(
     }
 
     // Crown the new top staker.
-    config.max_stake = proof_new.balance;
     config.top_staker = *proof_new_info.key;
+    config.top_staker_balance = proof_new.balance;
 
     Ok(())
 }
diff --git a/program/src/initialize.rs b/program/src/initialize.rs
index dc81adf..3a30d86 100644
--- a/program/src/initialize.rs
+++ b/program/src/initialize.rs
@@ -140,8 +140,9 @@ pub fn process_initialize<'a, 'info>(
     let config = Config::try_from_bytes_mut(&mut config_data)?;
     config.base_reward_rate = INITIAL_BASE_REWARD_RATE;
     config.last_reset_at = 0;
-    config.max_stake = 0;
+    config.min_difficulty = MIN_DIFFICULTY as u64;
     config.top_staker = Pubkey::new_from_array([0; 32]);
+    config.top_staker_balance = 0;
 
     // Initialize treasury
     create_pda(
diff --git a/program/src/mine.rs b/program/src/mine.rs
index cf016e0..f60b8a5 100644
--- a/program/src/mine.rs
+++ b/program/src/mine.rs
@@ -89,25 +89,30 @@ pub fn process_mine<'a, 'info>(
     // Validate hash satisfies the minimnum difficulty.
     let hash = solution.to_hash();
     let difficulty = hash.difficulty();
-    sol_log(&format!("Diff {}", difficulty));
-    if difficulty.lt(&MIN_DIFFICULTY) {
+    if difficulty.lt(&(config.min_difficulty as u32)) {
         return Err(OreError::HashTooEasy.into());
     }
+
+    // Normalize difficulty and calculate reward rate
+    let normalized_difficulty = difficulty
+        .checked_sub(config.min_difficulty as u32)
+        .unwrap();
     let mut reward = config
         .base_reward_rate
-        .checked_mul(2u64.checked_pow(difficulty).unwrap())
+        .checked_mul(2u64.checked_pow(normalized_difficulty).unwrap())
         .unwrap();
+    sol_log(&format!("Diff {}", difficulty));
 
     // Apply staking multiplier.
     // If user has greater than or equal to the max stake on the network, they receive 2x multiplier.
     // Any stake less than this will receives between 1x and 2x multipler. The multipler is only active
     // if the miner's last stake deposit was more than one minute ago.
     let t = clock.unix_timestamp;
-    if config.max_stake.gt(&0) && proof.last_stake_at.saturating_add(ONE_MINUTE).le(&t) {
+    if config.top_staker_balance.gt(&0) && proof.last_stake_at.saturating_add(ONE_MINUTE).le(&t) {
         let staking_reward = (reward as u128)
-            .checked_mul(proof.balance.min(config.max_stake) as u128)
+            .checked_mul(proof.balance.min(config.top_staker_balance) as u128)
             .unwrap()
-            .checked_div(config.max_stake as u128)
+            .checked_div(config.top_staker_balance as u128)
             .unwrap() as u64;
         reward = reward.checked_add(staking_reward).unwrap();
     }