Cost Savings Through Improved Cast Blasts
Document type: Case Study
Categories: Case Study

CASE STUDY

COST SAVINGS THROUGH IMPROVED CAST BLASTS

$ %
 $500,500 IN COST 7.54% EFFECTIVE 19% DECREASE
 SAVINGS CAST INCREASE BULLDOZER HOURS

l overburden removal costs. A 140-foot The data for the comparison between the control cut and
control cut and a 140-foot experimental cut were used to the experimental cut came from multiple sources. The
compare cost records and casting data collected by the unit costs and material volumes were provided by the
customer and by DynoConsult. customer. This data is collected and compiled monthly,
 and the customer evaluates and verifies the accuracy of
 their drill and blast data. Unit Costs
 All cast performance data was collected by DynoConsult
 Drill (USD/ft) $0.65 as part of DynoConsult’s work with the customer. This
 data is collected with a drone and analyzed using CAD
 Dozer Cost (USD/hr) $250.00 tools. The material volume and location before and after
 each blast forms the basis for short-term mine planning
 and cost tracking. The combination of cost data and cast
 Dozer Production 305
 performance data for the control and experimental cuts
 Rate (Icy/hr)
 allows the appropriate comparisons to be made. Avg. % Swell (Cut 14) 24.42%

Avg. % Swell (Cut 15) 27.47%

Table 1. Input variables used in cost comparisons.

SUMMARY PROJECT GOALS
IMPROVED BLASTS TO SAVE COAL MINE $500K DETERMINING ECONOMIC IMPACT
ANNUALLY The primary goal of this project was to reduce costs
DynoConsult gathered and analyzed data at a coal mine to through effective blasting. To determine if increased drill
determine if changes to drill and blast practices reduced and blast costs were offset by a consequential reduction
overall costs. in secondary material movement costs, DynoConsult
 analyzed the data collected. After a cast analysis showed
 a higher effective cast in the experimental cut compared to
 BACKGROUND the control cut, the customer wanted verification that the
 reduced rehandle material would lead to lower bulldozer
DRILLING AND BLASTING OPTIMIZATION pushing costs. An area coal mine planned to run experimental changes
to their drill and blast program to reduce costs through
efficient blasting. They enlisted the help of Dyno Nobel’s TECHNOLOGY APPLIED
DynoConsult team to analyze the effectiveness of changes
to the drill and blast practices and determine if they would DATA COLLECTION AND SOURCING
reduce overall overburden removal costs. A 140-foot The data for the comparison between the control cut and
control cut and a 140-foot experimental cut were used to the experimental cut came from multiple sources.

Key Comparisons
 VALUE ADDED
 Cut 14 Cut 15
DATA ANALYSIS AND RESULTS Rows (Avg.) 5.45 6.32
 Burden (Avg. ft) 24.01 21.33
The five key components of this comparison are pattern
data, explosives data, drill data, cast data, and dozer data. Spacing (Avg. ft) 22.11 21.70
The primary change between the two cuts was the layout Volume (Total BCY) 939,361 816,898
of the drill pattern. In the experimental cut, the number of Total Bulk 1,038,284 1,060,664
rows was increased, and the burden and spacing were Explosive (Lbs)
reduced. Part of that change was the introduction of Powder Factor 1.1053 1.2984
a variable burden, where the burdens on the face were (Lbs/BCY)
increased and burdens at the back of the shot were
decreased. Total Cast % 36.76% 43.37%
 Effective Cast % 17.43% 24.97%
The variable burden design is responsible for much of the Dozer Push 965,069 781,296
increase in casting performance because it allows material Volume (LCY)
in the front of the blast to move further into the effective Total Dozer Hrs 3.164.2 2,561.6
cast zone. This accompanies an increase in powder factor
 Drill Costs (USD/BCY) $0.0345 $0.0387
between the two cuts. Cast performance data collected by
DynoConsult demonstrates the improved casting results. Blast Costs (USD/BCY) $0.2692 $0.3122
The resulting cast increase reduced the amount of work Dozer Costs (USD/BCY) $0.8421 $0.7839
for the bulldozers.

terial not in the effective cast is
moved by bulldozers. If any material is moved by truck
and shovel, then the cost savings will increase. The other
major benefit is the reduction in bulldozer hours. Having
bulldozers available for additional work further reduces
costs and improves overall efficiency of the mine.

Because of the overall cost savings, the customer
implemented the experimental changes as part of their
new standard drill and blast practices once the comparison
was completed.

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onsult demonstrates the improved casting results. Blast Costs (USD/BCY) $0.2692 $0.3122
The resulting cast increase reduced the amount of work Dozer Costs (USD/BCY) $0.8421 $0.7839
for the bulldozers. Total Costs (USD/BCY) $1.1459 $1.1349

CASE STUDY

There is a difference in bank volume between the two Table 2. Comparison of data between the control and
cuts. The change in bank volume between the cuts experimental cuts. necessitates all comparisons be normalized to bank cubic
yards, resulting in the summary results being relayed with
the units per bank cubic yard. The results summary can
be seen in Table 2. Looking at the total and effective cast Results Summary
values between the cuts, there is a noticeable change. Effective Cast Change +7.54%
The increase in powder factor resulted in an effective
cast increase from 17.43% to 24.97%. Over a year of Dozer Hour Change -19.04%
production at this site, the effective casting increase will
reduce rehandle material by 3,430,000 bank cubic yards Cost Savings Per $0.011
(BCY). This increase in casting volume accounts for much Unit (USD/BCY)
the 19% decrease in bulldozer hours between the cuts. Annual Direct Cost $500,500.00
The change in pattern design is projected to save the Reduction
mine $500,500.00 annually on direct material movement Table 3. Summary of end results. costs, assuming all material not in the effective cast is
moved by bulldozers. If any material is moved by truck
and shovel, then the cost savings will increase. The other
major benefit is the reduction in bulldozer hours.