diff --git a/miner/miner.go b/miner/miner.go
index a87faf0aa5..939eb5b73e 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -43,9 +43,9 @@ type Backend interface {
 
 // Config is the configuration parameters of mining.
 type Config struct {
-	Validator          common.Address `toml:",omitempty"` // Public address for block signing and randomness (default = first account)
-	ExtraData          hexutil.Bytes  `toml:",omitempty"` // Block extra data set by the miner
-	FeeCurrencyDefault float64 // Default fraction of block gas limit
+	Validator          common.Address             `toml:",omitempty"` // Public address for block signing and randomness (default = first account)
+	ExtraData          hexutil.Bytes              `toml:",omitempty"` // Block extra data set by the miner
+	FeeCurrencyDefault float64                    // Default fraction of block gas limit
 	FeeCurrencyLimits  map[common.Address]float64 // Fee currency-to-limit fraction mapping
 }