diff --git a/src/main.rs b/src/main.rs
index c399ab5e2bdd858462c08d34329eb31c8f67260a..d081a6307d837e0f3e7f88f3190bd2505cba39fc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -86,6 +86,8 @@ struct MineParams {
     rpc_url: Option<String>,
     // Chain ID
     chain_id: Option<u64>,
+    /// Desired VDF mean duration in seconds
+    desired_vdf_duration: Option<u64>,
 }
 
 async fn init() -> (u64, String) {
@@ -217,8 +219,6 @@ async fn main() -> Result<(), anyhow::Error> {
             if params.chain_id.clone().is_some() {
                 chain_id = params.chain_id.unwrap();
             }
-            // println!("Processing {:?}", params.file);
-            // csv::Reader::from_path(path)
             let records = read_csv(csv::Reader::from_path(params.file.clone())?);
             if let Err(err) = records {
                 error!("error running example: {}", err);
@@ -444,13 +444,26 @@ async fn main() -> Result<(), anyhow::Error> {
             let miner_addr = wallet.address();
             info!("Mining with 0x{:02x} ...", miner_addr);
 
-            let behavior = get_miner_behavior(wallet, chain_id, miner_addr);
-            // SEND IT
             let provider = Provider::<Http>::try_from(rpc_url.clone()).unwrap();
+            let latest_block = provider.get_block(BlockNumber::Latest).await;
+            let network_difficulty = Some(
+                ethnum::U256::from_str(&latest_block.unwrap().unwrap().difficulty.to_string())
+                    .unwrap(),
+            );
+
+            let behavior = get_miner_behavior(
+                wallet,
+                chain_id,
+                miner_addr,
+                network_difficulty,
+                params.desired_vdf_duration,
+            );
+
             debug!(
                 "Miner behavior: {:?}",
                 serde_json::to_string(&behavior.clone())
             );
+            // SEND IT
             let block = provider
                 .request::<[Behavior; 1], Block>("emc_mine", [behavior])
                 .await
diff --git a/src/utils/miner.rs b/src/utils/miner.rs
index 48d6eaa5c95ad06551b18164496fcf167f728759..4afe05246f9c91bc27f7a58df4e2dd93844dbc29 100644
--- a/src/utils/miner.rs
+++ b/src/utils/miner.rs
@@ -13,17 +13,40 @@ use ethers::{
 use ethnum::U256;
 
 /// Get a RPC Behavior for miner with default values, ready to send.
-pub fn get_miner_behavior(wallet: LocalWallet, chain_id: u64, to: Address) -> Behavior {
+pub fn get_miner_behavior(
+    wallet: LocalWallet,
+    chain_id: u64,
+    to: Address,
+    network_difficulty: Option<U256>,
+    desired_vdf_duration: Option<u64>,
+) -> Behavior {
     let now = SystemTime::now()
         .duration_since(SystemTime::UNIX_EPOCH)
         .unwrap()
         .as_secs();
 
+    // const VDF_DIFFICULTY_FOR_10_MIN: u64 = 72;
+    // Mean VDF difficulty per sec = 72/600 on current machine (Macbook M1) and a hash maxed to 1 day.
+    // for a network difficulty of 1000000
+    const MEAN_VDF_DIFFICULTY_PER_SEC: u64 = 12;
+
+    let quantity = match network_difficulty {
+        Some(net_dif) => match desired_vdf_duration {
+            Some(vdf_dur) => net_dif
+                .saturating_mul(U256::from(MEAN_VDF_DIFFICULTY_PER_SEC * vdf_dur))
+                .saturating_div(U256::from(1000000_u128)),
+            _ => net_dif
+                .saturating_mul(U256::from(MEAN_VDF_DIFFICULTY_PER_SEC * 60))
+                .saturating_div(U256::from(1000000_u128)),
+        },
+        //  default 1 min
+        _ => U256::from(MEAN_VDF_DIFFICULTY_PER_SEC * 60),
+    };
     let behavior_msg = BehaviorMessage{
          chain_id: U64::from(chain_id),
          to:Some(to),
          timestamp: U64::from(now),
-         quantity: U256::from(210000_u64),
+         quantity,
          input: Bytes::from("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") };
 
     // let behavior = wallet.