diff --git a/utils/staking-miner/src/monitor.rs b/utils/staking-miner/src/monitor.rs
index bfc075668e66..2395c7b7fc69 100644
--- a/utils/staking-miner/src/monitor.rs
+++ b/utils/staking-miner/src/monitor.rs
@@ -24,7 +24,8 @@ use jsonrpsee::core::Error as RpcError;
 use sc_transaction_pool_api::TransactionStatus;
 use sp_core::storage::StorageKey;
 use sp_runtime::Perbill;
-use tokio::sync::mpsc;
+use std::sync::Arc;
+use tokio::sync::{mpsc, Mutex};
 use EPM::{signed::SubmissionIndicesOf, SignedSubmissionOf};
 
 /// Ensure that now is the signed phase.
@@ -170,6 +171,7 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 
 		let mut subscription = heads_subscription().await?;
 		let (tx, mut rx) = mpsc::unbounded_channel::<StakingMinerError>();
+		let submit_lock = Arc::new(Mutex::new(()));
 
 		loop {
 			let at = tokio::select! {
@@ -201,9 +203,8 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 			// Spawn task and non-recoverable errors are sent back to the main task
 			// such as if the connection has been closed.
 			tokio::spawn(
-				send_and_watch_extrinsic(rpc.clone(), tx.clone(), at, signer.clone(), config.clone())
+				send_and_watch_extrinsic(rpc.clone(), tx.clone(), at, signer.clone(), config.clone(), submit_lock.clone())
 			);
-
 		}
 
 		/// Construct extrinsic at given block and watch it.
@@ -213,6 +214,7 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 			at: Header,
 			signer: Signer,
 			config: MonitorConfig,
+			submit_lock: Arc<Mutex<()>>,
 		) {
 
 			async fn flatten<T>(
@@ -255,6 +257,8 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 				return;
 			}
 
+			let _lock = submit_lock.lock().await;
+
 			let mut ext = match crate::create_election_ext::<Runtime, Block>(rpc.clone(), Some(hash), vec![]).await {
 				Ok(ext) => ext,
 				Err(err) => {
@@ -302,6 +306,7 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 
 			let rpc1 = rpc.clone();
 			let rpc2 = rpc.clone();
+			let rpc3 = rpc.clone();
 
 			let latest_head = match get_latest_head::<Runtime>(&rpc, &config.listen).await {
 				Ok(hash) => hash,
@@ -325,10 +330,16 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 				ensure_signed_phase::<Runtime, Block>(&rpc2, latest_head).await
 			});
 
+			let account = signer.account.clone();
+			let no_prev_sol_fut = tokio::spawn(async move {
+				ensure_no_previous_solution::<Runtime, Block>(&rpc3, latest_head, &account).await
+			});
+
 			// Run the calls in parallel and return once all has completed or any failed.
 			if let Err(err) = tokio::try_join!(
 				flatten(ensure_strategy_met_fut),
 				flatten(ensure_signed_phase_fut),
+				flatten(no_prev_sol_fut),
 			) {
 				log::debug!(target: LOG_TARGET, "Skipping to submit at block {}; {}", at.number, err);
 				return;
diff --git a/utils/staking-miner/src/rpc.rs b/utils/staking-miner/src/rpc.rs
index 8929afcbe656..1da24b4aae34 100644
--- a/utils/staking-miner/src/rpc.rs
+++ b/utils/staking-miner/src/rpc.rs
@@ -131,6 +131,7 @@ impl SharedRpcClient {
 			.connection_timeout(connection_timeout)
 			.max_request_body_size(u32::MAX)
 			.request_timeout(request_timeout)
+			.max_concurrent_requests(u32::MAX as usize)
 			.build(uri)
 			.await?;
 		Ok(Self(Arc::new(client)))