diff --git a/ethcore/src/client/test_client.rs b/ethcore/src/client/test_client.rs
index b2230af7b..893cdae03 100644
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@@ -16,6 +16,7 @@
 
 //! Test client.
 
+use std::sync::atomic::{AtomicUsize, Ordering as AtomicOrder};
 use util::*;
 use transaction::{Transaction, LocalizedTransaction, SignedTransaction, Action};
 use blockchain::TreeRoute;
@@ -54,6 +55,8 @@ pub struct TestBlockChainClient {
 	pub execution_result: RwLock<Option<Executed>>,
 	/// Transaction receipts.
 	pub receipts: RwLock<HashMap<TransactionId, LocalizedReceipt>>,
+	/// Block queue size.
+	pub queue_size: AtomicUsize,
 }
 
 #[derive(Clone)]
@@ -90,6 +93,7 @@ impl TestBlockChainClient {
 			code: RwLock::new(HashMap::new()),
 			execution_result: RwLock::new(None),
 			receipts: RwLock::new(HashMap::new()),
+			queue_size: AtomicUsize::new(0),
 		};
 		client.add_blocks(1, EachBlockWith::Nothing); // add genesis block
 		client.genesis_hash = client.last_hash.read().unwrap().clone();
@@ -121,6 +125,11 @@ impl TestBlockChainClient {
 		self.storage.write().unwrap().insert((address, position), value);
 	}
 
+	/// Set block queue size for testing
+	pub fn set_queue_size(&self, size: usize) {
+		self.queue_size.store(size, AtomicOrder::Relaxed);
+	}
+
 	/// Add blocks to test client.
 	pub fn add_blocks(&self, count: usize, with: EachBlockWith) {
 		let len = self.numbers.read().unwrap().len();
@@ -383,7 +392,7 @@ impl BlockChainClient for TestBlockChainClient {
 
 	fn queue_info(&self) -> BlockQueueInfo {
 		BlockQueueInfo {
-			verified_queue_size: 0,
+			verified_queue_size: self.queue_size.load(AtomicOrder::Relaxed),
 			unverified_queue_size: 0,
 			verifying_queue_size: 0,
 			max_queue_size: 0,
diff --git a/miner/src/miner.rs b/miner/src/miner.rs
index 508fcffb4..e989fa495 100644
--- a/miner/src/miner.rs
+++ b/miner/src/miner.rs
@@ -165,28 +165,32 @@ impl MinerService for Miner {
 	}
 
 	fn update_sealing(&self, chain: &BlockChainClient) {
-		let should_disable_sealing = {
+		if self.sealing_enabled.load(atomic::Ordering::Relaxed) {
 			let current_no = chain.chain_info().best_block_number;
-			let last_request = self.sealing_block_last_request.lock().unwrap();
-			let is_greater = current_no > *last_request;
-			is_greater && current_no - *last_request > SEALING_TIMEOUT_IN_BLOCKS
-		};
+			let last_request = *self.sealing_block_last_request.lock().unwrap();
+			let should_disable_sealing = current_no > last_request && current_no - last_request > SEALING_TIMEOUT_IN_BLOCKS;
 
-		if should_disable_sealing {
-			self.sealing_enabled.store(false, atomic::Ordering::Relaxed);
-			*self.sealing_block.lock().unwrap() = None;
-		} else if self.sealing_enabled.load(atomic::Ordering::Relaxed) {
-			self.prepare_sealing(chain);
+			if should_disable_sealing {
+				trace!(target: "miner", "Miner sleeping (current {}, last {})", current_no, last_request);
+				self.sealing_enabled.store(false, atomic::Ordering::Relaxed);
+				*self.sealing_block.lock().unwrap() = None;
+			} else {
+				self.prepare_sealing(chain);
+			}
 		}
 	}
 
 	fn sealing_block(&self, chain: &BlockChainClient) -> &Mutex<Option<ClosedBlock>> {
 		if self.sealing_block.lock().unwrap().is_none() {
 			self.sealing_enabled.store(true, atomic::Ordering::Relaxed);
-
 			self.prepare_sealing(chain);
 		}
-		*self.sealing_block_last_request.lock().unwrap() = chain.chain_info().best_block_number;
+		let mut sealing_block_last_request = self.sealing_block_last_request.lock().unwrap();
+		let best_number = chain.chain_info().best_block_number;
+		if *sealing_block_last_request != best_number {
+			trace!(target: "miner", "Miner received request (was {}, now {}) - waking up.", *sealing_block_last_request, best_number);
+			*sealing_block_last_request = best_number;
+		}
 		&self.sealing_block
 	}
 
diff --git a/rpc/src/v1/impls/eth.rs b/rpc/src/v1/impls/eth.rs
index a065392d5..99f6eda3e 100644
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@@ -197,6 +197,8 @@ impl<C, S, A, M, EM> EthClient<C, S, A, M, EM>
 	}
 }
 
+const MAX_QUEUE_SIZE_TO_MINE_ON: usize = 4;	// because uncles go back 6.
+
 impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 	where C: BlockChainClient + 'static,
 		  S: SyncProvider + 'static,
@@ -398,10 +400,12 @@ impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 		match params {
 			Params::None => {
 				let client = take_weak!(self.client);
-				// check if we're still syncing and return empty strings int that case
+				// check if we're still syncing and return empty strings in that case
 				{
-					let sync = take_weak!(self.sync);
-					if sync.status().state != SyncState::Idle && client.queue_info().is_empty() {
+					//TODO: check if initial sync is complete here
+					//let sync = take_weak!(self.sync);
+					if /*sync.status().state != SyncState::Idle ||*/ client.queue_info().total_queue_size() > MAX_QUEUE_SIZE_TO_MINE_ON {
+						trace!(target: "miner", "Syncing. Cannot give any work.");
 						return to_value(&(String::new(), String::new(), String::new()));
 					}
 				}
diff --git a/rpc/src/v1/tests/eth.rs b/rpc/src/v1/tests/eth.rs
index 4564076eb..209b95ded 100644
--- a/rpc/src/v1/tests/eth.rs
+++ b/rpc/src/v1/tests/eth.rs
@@ -476,7 +476,8 @@ fn rpc_eth_compile_serpent() {
 
 #[test]
 fn returns_no_work_if_cant_mine() {
-	let eth_tester = EthTester::default();
+	let mut eth_tester = EthTester::default();
+	eth_tester.client.set_queue_size(10);
 
 	let request = r#"{"jsonrpc": "2.0", "method": "eth_getWork", "params": [], "id": 1}"#;
 	let response = r#"{"jsonrpc":"2.0","result":["","",""],"id":1}"#;