Merge mining, also called merged mining, lets miners use the same proof-of-work hashing to help secure more than one blockchain and potentially earn rewards from each.

For example, a miner connected to a pool that supports Litecoin and Dogecoin merged mining can use one Scrypt ASIC to contribute to both networks. The machine does not divide its hashrate between the two coins or run a separate hashing workload for each.

The blockchains remain separate. What they share is the mining work, through a mechanism called Auxiliary Proof of Work (AuxPoW).

LTC and DOGE: A Practical Example

Litecoin and Dogecoin are a well-known example of merged mining. Both use the Scrypt hashing algorithm. In 2014, Dogecoin was modified to accept AuxPoW, allowing work performed when mining Litecoin to also help secure Dogecoin. Dogecoin’s mining documentation explains this change.

In this arrangement, Litecoin is the parent chain, and Dogecoin is the auxiliary chain. Litecoin and Dogecoin retain their own block histories, block rewards, and difficulty adjustments. They do not become a single blockchain.

Merged mining is not limited to these two networks. Namecoin was the first blockchain to implement merged mining and can use Bitcoin as its parent chain. Namecoin provides another established example.

How Merge Mining Works

The parent chain is the blockchain whose candidate block header the miner hashes.

The auxiliary chain accepts proof linked to that work under its own consensus rules. For the AuxPoW setups described here, sharing a compatible proof-of-work algorithm is not enough: the auxiliary chain must also support AuxPoW validation.

In a pool-based setup, the process generally works like this:

1. The pool prepares work for both chains. It builds candidate blocks and places a commitment—a reference linking the auxiliary block to the mining work—in the parent block’s coinbase transaction.
2. The ASIC performs the hashing. It works on the job supplied by the pool without splitting its hashrate between chains.
3. The pool checks submitted work. It compares the proof-of-work hash against each chain’s block target. If the work qualifies, the pool submits the corresponding block and any required proof to that network.
4. Rewards follow the pool’s rules. The pool calculates and distributes eligible rewards according to its payout rules, which are separate from AuxPoW itself.

A hash does not have to meet both chains’ block targets. If the auxiliary chain has an easier target, a hash can qualify for an auxiliary block without qualifying for a parent-chain block. An easier target is numerically higher, so more hash results meet it.

This lets the same hashing work contribute to multiple networks without requiring a separate proof-of-work hashing workload. The pool still handles additional tasks, such as preparing auxiliary blocks and submitting proofs.

Does Merge Mining Split Hashrate?

No. In a standard merged-mining setup, the hardware does not allocate part of its hashrate to the parent chain and the rest to an auxiliary chain.

Instead, the pool checks the same work against each chain’s target. A hash may qualify for one chain, both chains, or neither chain’s block target. The networks independently validate the blocks submitted to them.

Why Auxiliary Chains Use Merge Mining

Smaller proof-of-work networks can struggle to attract enough mining participation to resist attacks. Merged mining allows an auxiliary chain to draw on hashing work already being performed for another network.

However, an auxiliary chain does not automatically inherit all of the parent chain’s security. The benefit depends on the hashrate actually participating in merged mining for that auxiliary chain. How that hashrate is distributed among miners and pools also matters; hashrate alone does not guarantee security.

For miners, the appeal is the possibility of earning additional coins from the same hashing work. Those rewards have their own market values, and pools set their own rules for calculating, crediting, and paying them out. Additional coin rewards do not guarantee a particular fiat return or profit.

What to Check Before Using a Merge-Mining Pool

When mining through a pool, merged-mining support depends on the pool’s implementation. Before connecting, check:

• Which auxiliary coins the pool supports for your primary mining coin
• Whether your chosen payout method qualifies for merged-mining rewards
• How those rewards are calculated and which assets are credited
• When rewards are settled and how withdrawals or conversions work
• Any applicable pool or conversion fees

These rules vary by pool and coin. Check the pool’s current documentation instead of assuming that every pool handles merged mining the same way.

ViaBTC Merged Mining

ViaBTC’s documentation lists NMC and FB as merged-mining rewards for its BTC pool, and DOGE, BELLS, PEP, and DINGO for its LTC pool. Miners using either PPS+ or PPLNS are eligible. ViaBTC merged-mining overview

For LTC miners, the listed auxiliary-coin rewards are distributed under PPLNS and settled every two hours. An LTC miner choosing PPS+ can therefore receive LTC rewards under PPS+ while their merged-mining rewards follow PPLNS rules. ViaBTC LTC merged-mining tutorial

Eligible miners connected to ViaBTC’s LTC pool do not need a second machine or separate merged-mining configuration. The pool handles the auxiliary-chain work and credits rewards to the linked ViaBTC account. Conversion and withdrawal options follow the rules for the relevant asset.

FAQ

Is merge mining the same as dual mining?

No. Merged mining reuses the same proof-of-work hashing across compatible blockchains. Dual mining typically runs separate mining algorithms simultaneously, often on the same GPU, rather than reusing one proof of work.

Does merge mining require two ASICs?

No. One compatible ASIC can participate through a pool that supports merged mining. In that setup, the pool handles auxiliary-block preparation and proof submission.

Does merge mining split my hashrate between chains?

No. The same hashing work is checked against each chain’s target; the hardware does not divide its hashrate between the chains.

Can any two coins be merge-mined together?

No. For the AuxPoW setups described here, the chains need compatible proof-of-work hashing, and the auxiliary chain must support AuxPoW validation. Sharing a hashing algorithm is not enough.

Is merged-mining revenue guaranteed?

No. The amount a miner receives depends on the pool’s payout rules and the auxiliary coin’s reward structure. Under a PPLNS arrangement, rewards also depend on blocks found by the pool and the miner’s eligible shares. The fiat value of those coins can change with market prices.

Does an auxiliary chain inherit all of the parent chain’s security?

No. Only hashrate participating in merged mining for that auxiliary chain contributes to it. The distribution of that hashrate also matters.

References

• Dogecoin, Mining Dogecoin
• Namecoin, Official website
• Bitcoin Wiki, Merged Mining Specification
• ViaBTC Help Center, What Is Merged Mining?
• ViaBTC Help Center, LTC Merged Mining Coins Mining Tutorial