In Old School RuneScape, few methods combine profitability and skilling efficiency as cleanly as the Blast Furnace. If you’re looking for a consistent way to earn up to 2 million GP per hour while training Smithing, this is one of the most reliable systems in the game-making it a strong alternative to players who might otherwise consider options like buy OSRS gold. It removes RNG entirely and replaces it with a repeatable, optimized loop that scales with your efficiency.

What Is the Blast Furnace?

The Blast Furnace is a minigame located in Keldagrim that allows players to smelt ores into bars using half the normal coal requirement. This is the core mechanic that makes it so profitable. Bars like steel, mithril, adamantite, and runite normally require large amounts of coal, but here that cost is reduced by 50%, dramatically increasing margins.

Requirements to Start

To access the Blast Furnace efficiently, you need a few key unlocks:

· Completion of the The Giant Dwarf (or at least partial progress to enter Keldagrim)

· Level 60 Smithing (to avoid a 2,500 GP fee every 10 minutes)

· A coal bag from Motherlode Mine (essential for efficiency)

· Ice gloves from White Wolf Mountain (lets you collect bars instantly)

Without the coal bag and ice gloves, your hourly rates drop significantly, so treat them as mandatory.

Getting There and Setup

The fastest access is via the minigame teleport or the Keldagrim minecart system. Once inside, always use official worlds such as 358, 386, or 387, where dwarves operate the furnace automatically.

Before starting, deposit coins into the coffer. Around 72,000 GP funds one hour of operation. If the coffer runs out, the furnace stops—killing your efficiency.

Best Bars for Profit

Profitability depends heavily on Grand Exchange prices, so always check margins before committing. That said, here’s a general ranking:

Runite Bars (Level 85 Smithing)
This is the highest profit method. You can produce roughly 900–1,000 bars per hour, with profits ranging from 1.7M to 2M GP/hour. The downside is high upfront cost due to expensive runite ore.

Adamantite Bars (Level 70 Smithing)
A strong mid-to-high-tier option. Producing 2,400–2,700 bars per hour, profits can reach around 1.5M–1.8M GP/hour depending on margins. This is often the most balanced method for consistent returns.

Mithril Bars (Level 50 Smithing, 60 recommended)
Lower profit per bar but cheaper to start. With 2,500–3,000 bars per hour, total profit can still reach ~1.2M–1.7M GP/hour.

Steel Bars (Level 30 Smithing)
Very high volume (up to 5,000/hour), but thin margins. Best suited for low-level players building initial capital.

XP Rates and Training Efficiency

The Blast Furnace is not just about profit-it’s also one of the fastest Smithing training methods in the game:

· Steel bars: ~900K XP/hour

· Mithril bars: ~600K XP/hour

· Adamantite bars: up to ~1.4M XP/hour

· Runite bars: ~200K XP/hour

· Gold bars (with gauntlets): ~380K XP/hour

For pure XP, gold bars are optimal. For profit-focused training, adamantite and runite dominate.

Inventory Setups

Efficiency depends on precise inventory management:

· Runite bars: Coal bag (27 coal), 13 coal in inventory, 10 runite ore

· Adamantite bars: Coal bag full, 12 coal inventory, 13 adamantite ore

· Mithril bars: Coal bag ~20 coal, rest mithril ore

· Steel bars: Coal bag full, inventory filled with iron ore

These setups minimize downtime and maximize throughput.

The Core Loop

Every run follows the same cycle:

· Bank: Fill coal bag and inventory with ore

· Conveyor belt: Deposit ore, then coal

· Return to bank: Withdraw additional coal if needed

· Collect bars from dispenser (with ice gloves)

· Bank bars and repeat

At optimal efficiency, each loop takes 30–45 seconds.

Optimization Tips

First, always check Grand Exchange prices before each session. Margins fluctuate constantly, and yesterday’s best method may not be optimal today.

Second, stick to official worlds. Manual operation slows production and reduces profit.

Third, maintain stamina. Use stamina potions every trip and keep your coffer funded to avoid interruptions.

Final Takeaway

The Blast Furnace stands out in Old School RuneScape because it aligns two core goals: profit and progression. With proper setup and execution, you can earn up to 2 million GP per hour while pushing toward 99 Smithing at competitive XP rates-but if you’re looking to accelerate your progress even further, many players also choose to supplement their grind with cheap OSRS gold to get ahead faster. It’s a deterministic system-no luck, no variance-just clean, repeatable efficiency that you can scale alongside your resources.