Feasibility Study Cost Estimates ©2002 Dr. Bradley C Paul

Feasibility Study n Processes are actually worked out and planned – checked for technical flaws – checked for permit flaws n Format – Pre-feasibility may give you a lot of factored cost estimates – Start Shifting big ones to itemized cost estimates – Itemized estimates become more detailed

Feasibility Study Overviews n Major Cost Items are Identified – Quotes are secured on major cost items – Minor items tend to be listed with general comparison cost estimates attached. n Important error avoid - missing and double counting.

Pre-Feasibility/ Feasibility Contrast n Major Cost Items from Pre-Feasibility move either to Itemized Cost format or are expanded n Example - Our Mine Shaft could easily be a big cost – Advance rate likely to be 8 feet per day using 3 eight hour shifts in solid – Only get 2 feet day through first 200 feet of unconsolidated – Lets Detail the crew

Shafting Crew n Typical Sinking Crew would be 5 people – 4 laborers – 1 supervisor – doing rounds, support ect. (from SERPA) – wages $15.46/hr (1997 base from WMCS) – 4*24*$15.46 = $1,484/day – Time 100 days for first 200 ft n 69 days more for next 550 ft through solid rock – 169 days at $1,484/day = $250,823 – I’ll deal with supervisor later

Support People n Engineering/Technical Crew – 1 person (some would use 2) (3 for 3 shifts) SERPA – $16.15/hr 1997 cost WMCS – $388/day * 169 days = $65,504 n Mechanical Crew – 2 people (6 for 3 shifts) SERPA – $20.98/hr 1997 cost WMCS – $1007/day*169 days = $170,190

Surface Crews n Surface and Yard Workers 2 n Rate $11.89/hr – 2*$11.89*24*169 = $96,452 n Sinking Hoist Operator – $16.50/hr*24*169 = $66,924

Supervisory Crews n 1 supervisor/shift $23.94/hr – $23.94*24*169 = $97,101 n Total Labor Cost – $746,994 say $747,000 n Indexing Labor – $747,000* 17.89/16.15 = $827,500

The Burden of Burden n Workers get fringe benefits – health, vacation time etc. – government mandated programs n social security / medicare / unemployment / workers compensation n Often Expressed as a percentage of wage – Quarries around 30% – Metals commonly around 40% – Some coal may be 60% – WMCS estimates 36% for Shaft Sinking

Dropping the Burden on the Project n $827,500 * 1.36 = $1,125,000 n Explosives Cost – Rounds at 4 lbs/ton – Need to know concrete thickness n have about 15 inch thick (some squeeze for horizontal stress) n for 20 ft finished diameter - need 22.5 feet – with some over-excavation 23 feet – Rock density about 170 lb/ft^3 n 35.3 tons per foot of Advance

Having a Blast n 35.3 tons/ft * 4 lbs/ton = 141 lbs of explosive per foot of advance – 106,000 $1.54/lb = $163,000 n At about 1 round shot/day – 110 caps/day * 169 days = 18,590 caps each = $33,650 n Chord and Supplies about 50% of caps (no boosters here) – $16,824

Breaking Cost n $213,500 for explosives n Drilling Consumables at about 25% of explosives – $53,400 n Breaking Cost (less labor counted elsewhere) – $267,000 n Index to end 2002 – $267,000 * 149.7/149.1 = $268,000

Non-Labor Mucking Costs n At $2.50/ton (include disposal) – 35.3 tons/ft * $2.5 = $88.30/ft – for 750 ft $66,216 (current cost) n Concrete Cost – 23 ft outside diam - 20 ft inside – 3.75 cubic yard per foot of advance – Concrete at $80/cubic yard delivered to site – $225,000 for concrete

Other Supplies n Steel cost at about 1.5 times concrete – $337,500 – includes materials to advance utilities down shaft and put in guides for skips n Concrete and Steel – $562,500 n 10% for misc supplies – $56,250 total n Supplies Subtotal $618,750

Direct Cost of Shaft n Labor $1,125,400 + Breaking $268,000 + Mucking $66,200 + Supplies $618,750 n $2,078,350 n 10% contingency $2,286,200 n 15% contractor mark-up and mobilization – $2,629,000 n Note that we did consider some site specific problems with large amounts unconsolidated Overburden and ground stresses

Pre-Feasibility / Feasibility Contrast n At Order of Magnitude just scaled off of someone elses approximate cost n Pre-Feasibility was either a factored cost estimate or a simple itemized cost estimate (ie cost per foot of shaft) n At Feasibility stage it became a much more carefully itemized exercise – we were still flakey on cost of service lines pipes n As move to Budget Authorization likely bring in contractors to bid specifically on the job