diff --git a/db/src/lib.rs b/db/src/lib.rs
index 7415131e..7d6f771c 100644
--- a/db/src/lib.rs
+++ b/db/src/lib.rs
@@ -39,6 +39,8 @@ pub enum BlockLocation {
 	Side(u32),
 }
 
+pub type SharedStore = std::sync::Arc<Store + Send + Sync>;
+
 pub use best_block::BestBlock;
 pub use storage::{Storage, Store};
 pub use error::Error;
diff --git a/db/src/storage.rs b/db/src/storage.rs
index 09adf0c3..c9499460 100644
--- a/db/src/storage.rs
+++ b/db/src/storage.rs
@@ -2,7 +2,7 @@
 
 use std::{self, fs};
 use std::path::Path;
-use kvdb::{DBTransaction, Database, DatabaseConfig};
+use kvdb::{Database, DatabaseConfig};
 use byteorder::{LittleEndian, ByteOrder};
 use primitives::hash::H256;
 use primitives::bytes::Bytes;
@@ -11,7 +11,6 @@ use serialization;
 use chain::{self, RepresentH256};
 use parking_lot::RwLock;
 use transaction_meta::TransactionMeta;
-use std::collections::HashMap;
 
 use error::{Error, ConsistencyError, MetaError};
 use update_context::UpdateContext;
diff --git a/db/src/transaction_meta_provider.rs b/db/src/transaction_meta_provider.rs
index 8afa2af7..a85c92da 100644
--- a/db/src/transaction_meta_provider.rs
+++ b/db/src/transaction_meta_provider.rs
@@ -1,6 +1,5 @@
 use transaction_meta::TransactionMeta;
 use primitives::hash::H256;
-use primitives::bytes::Bytes;
 
 pub trait TransactionMetaProvider {
 	/// get transaction metadata
diff --git a/verification/src/chain_verifier.rs b/verification/src/chain_verifier.rs
index 06be939d..1d3f5be7 100644
--- a/verification/src/chain_verifier.rs
+++ b/verification/src/chain_verifier.rs
@@ -1,7 +1,5 @@
 //! Bitcoin chain verifier
 
-use std::sync::Arc;
-
 use db::{self, BlockRef, BlockLocation};
 use chain::{self, RepresentH256};
 use super::{Verify, VerificationResult, Chain, Error, TransactionError, ContinueVerify};
@@ -13,7 +11,7 @@ const MAX_BLOCK_SIGOPS: usize = 20000;
 const MAX_BLOCK_SIZE: usize = 1000000;
 
 pub struct ChainVerifier {
-	store: Arc<db::Store>,
+	store: db::SharedStore,
 	verify_p2sh: bool,
 	verify_clocktimeverify: bool,
 	skip_pow: bool,
@@ -21,7 +19,7 @@ pub struct ChainVerifier {
 }
 
 impl ChainVerifier {
-	pub fn new(store: Arc<db::Store>) -> Self {
+	pub fn new(store: db::SharedStore) -> Self {
 		ChainVerifier {
 			store: store,
 			verify_p2sh: false,
@@ -276,7 +274,7 @@ mod tests {
 
 	use super::ChainVerifier;
 	use super::super::{Verify, Chain, Error, TransactionError};
-	use db::{TestStorage, Storage, Store};
+	use db::{TestStorage, Storage, Store, BlockStapler};
 	use test_data;
 	use std::sync::Arc;
 	use devtools::RandomTempPath;