diff --git a/lib/mining/miner.js b/lib/mining/miner.js
index e6fdd7e0e..1a050465e 100644
--- a/lib/mining/miner.js
+++ b/lib/mining/miner.js
@@ -250,13 +250,6 @@ Miner.prototype.getAddress = function getAddress() {
  */
 
 Miner.prototype.assemble = function assemble(attempt) {
-  let priority = this.options.priorityWeight > 0;
-  const queue = new Heap(cmpRate);
-  const depMap = new Map();
-
-  if (priority)
-    queue.set(cmpPriority);
-
   if (!this.mempool) {
     attempt.refresh();
     return;
@@ -265,6 +258,14 @@ Miner.prototype.assemble = function assemble(attempt) {
   assert(this.mempool.tip === this.chain.tip.hash,
     'Mempool/chain tip mismatch! Unsafe to create block.');
 
+  const depMap = new Map();
+  const queue = new Heap(cmpRate);
+
+  let priority = this.options.priorityWeight > 0;
+
+  if (priority)
+    queue.set(cmpPriority);
+
   for (const entry of this.mempool.map.values()) {
     const item = BlockEntry.fromEntry(entry, attempt);
     const tx = item.tx;
@@ -296,6 +297,7 @@ Miner.prototype.assemble = function assemble(attempt) {
     const item = queue.shift();
     const tx = item.tx;
     const hash = item.hash;
+
     let weight = attempt.weight;
     let sigops = attempt.sigops;