Comparative value of steel

This is an attempt in putting a value in days worked on steel. Every step is made with propane and with no tools except the required ones. The large amount of steel is for avoiding rounding off errors as all calculations are done with full days of work.

For 100000g steel

104 days

• 54600g Iron
• 104 days
  • 72800g Iron ore
  • 139 days
    • 104250g Hematite
    • 139 days
  • 14560g Propane
  • 97 days
    • 19400g gas
    • 194 days
      • 4014g wood
      • 14 days
  • 145600g Limestone
  • 133 days
• 18200g Propane
• 122 days
  • 24400g gas
  • 244 days
    • 6710 wood
    • 23days
• 182000g Limestone
• 166 days

Sum --- 1375 days;

One day of work is worth 72.7 grams of steel.

Note: I realize this doesn't include time and cost for trasport, tools and machinery.