This presentation is about types of energy used in mines

1. ENERGY AUDITING IN MINES
PRESENTED BY:-
- ROHIT RAJ
Branch: M.Tech(MME), IIT(ISM) DHANBAD

2. OUTLINES
 Definition and objective of energy audit
 Areas of energy audit in mines
 Advantages of energy audit
 Types of energy audit
 Methodology of energy audit
 Energy audit instrument
 Conclusion

3. Definition and objectives of
energy audit

4. WHAT IS ENERGY AUDIT ?
 As per Indian Energy Conservation Act 2001,
Energy Audit is defined as:
“the verification, monitoring and analysis of use of energy
including submission of technical report containing
recommendations for improving energy efficiency with cost
benefit analysis and an action plan to reduce energy
consumption “

5. OBJECTIVE OF ENERGY AUDIT
 primary objective of Energy Audit is to determine ways to
reduce energy consumption per unit of product output or to
lower operating costs
 Energy Audit provides a “ bench-mark” for managing energy
in the organization
Benchmarking is a tool for understanding energy consumption patterns
and also to take requisite(necessary) measures for improving energy
efficiency.

6. AREAS OF ENERGY AUDIT IN MINES
END USE ENERGY TYPE INFLUENCE VARIABLES
Ventilation electricity, natural gas production, mine depth, mine
layout, outdoor temperature
Hoisting electricity production, mine depth,
hoist speed
compressors electricity production
pumps electricity production, depth of
locations
Underground equipment
(drills, bolters)
electricity production
Underground mobile
equipment
diesel production, distance
travelled, road grade
Underground fixed
equipment (crusher)
electricity production, ore hardness,
feed size, product size

7. ADVANTAGES OF ENERGY AUDIT
 Conserve non-renewable energy resources
 Protect the environment by reducing power generation
 Identify and minimize wastage

8. TYPES OF ENERGY AUDIT
Based on available resources, the size and type of mines and the
energy audit objective there are two types of Energy Audit
mainly:-
 Preliminary Energy Audit
 Detailed Audit

9. PRELIMINARY ENERGY AUDIT
 Determine energy consumption in the mines
 Estimate the scope for saving
 Identify immediate (especially no-cost/low-cost)
improvements/ savings
 Identify areas for more detailed study/measurement

10. DETAILED ENERGY AUDIT
 Energy consumption by type of energy by major equipment.
 Energy cost and tariff data
 Sources of energy supply
 Energy Management procedures and energy awareness
training programs within the establishment

11. Figure presents a Sankey diagram prepared
from the audit data to illustrate the energy
consumption allocated to the various end-
uses.

12.  Figure shows that ventilation, and
underground equipment were the main
electricity consuming activities.
However, the electricity consumption
from the auxiliary mine ventilation
system seemed low whereas the use
from drills and bolters appeared high.
Figure : Sankey diagram showing energy flows
Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the
flow quantity

13. E.g.-average rated power from all auxiliary
fans is 50 kW and it is assumed that these
had a 97.5% load factor.
And, the average rated power of the
hydraulic power equipment (bolters and
drills) is 75 kW but the average load factor
for electricity consuming is to be roughly
25%.Although the average rated power for
the drills and bolters was higher than that
of the auxiliary fans, the load factor and the
number of equipment was lower. But, there
were more than 50 auxiliary fans in the
inventory whereas there was a total of 15
drills and bolters. Thus it is concluded that
the electricity consumption from the
auxiliary ventilation fans would be greater
than that of the drills and bolters.
A high load factor means power usage is
relatively constant. Low load factor shows that
occasionally a high demand is set. A low load
factor means that we are using electricity
inefficientlyFigure : Sankey diagram prepared from audit data
𝐥𝐨𝐚𝐝 𝐟𝐚𝐜𝐭𝐨𝐫 % =
𝐭𝐨𝐭𝐚𝐥 𝐤𝐢𝐥𝐨𝐰𝐚𝐭𝐭−𝐡𝐨𝐮𝐫𝐬 (𝐤𝐖𝐡) 𝐜𝐨𝐧𝐬𝐮𝐦𝐞𝐝 𝐢𝐧 𝐚 𝐝𝐞𝐬𝐢𝐠𝐧𝐚𝐭𝐞𝐝 𝐩𝐞𝐫𝐢𝐨𝐝
𝐦𝐚𝐱𝐢𝐦𝐮𝐦 𝐝𝐞𝐦𝐚𝐧𝐝 𝐢𝐧 𝐤𝐢𝐥𝐨𝐰𝐚𝐭𝐭𝐬 𝐤𝐖 ∗ 𝐭𝐡𝐞 𝐧𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐡𝐨𝐮𝐫𝐬 𝐢𝐧 𝐭𝐡𝐞 𝐩𝐞𝐫𝐢𝐨𝐝.

14. Subsequently a revised Sankey
diagram was prepared from the
revised energy consumption values
 It can be seen from Figure that the end-
uses(ultimate uses) consuming the most
energy on were: ventilation, and
underground mobile equipment.

15. METHODOLOGY OF ENERGY AUDIT
 Install energy meters on main ventilation fans
 Install meters to obtain electricity use from skip and cage hoists
 Obtain ventilation survey data from ventilation to estimate electricity use
from auxiliary ventilation system.
 Install meter to gather electricity use from underground fixed equipment
(crusher)
 Include blasting as an additional end-use
 Obtain diesel consumption for underground mobile equipment and
underground equipment (drills, bolters…) from engine management
systems

16. INSTRUMENTS USED IN ENERGY
AUDIT
 Energy Meter : An electricity meter measures the amount of
electric energy consumed by an electrically powered device.

17. Speed Measurements: In any audit exercise speed
measurements are critical as that may change with frequency,
belt slip and loading. A simple tachometer is a contact type
instrument which can be used where direct access is possible.

18. Pitot Tube and manometer: Air velocity in ducts can be
measured using a pitot tube and inclined manometer for
calculation of flows.
𝑊 =
P×Q
ηfan×ηmotor
where 𝑊 is the power supply(kW), 𝑃 is
fan
pressure (kPa), 𝑄 is the airflow rate
(m3/s), 𝜂𝑓𝑎𝑛 is the fan efficiency, and
𝜂𝑚𝑜𝑡𝑜𝑟 is the motor efficiency

19. CONCLUSION
 For an improved energy audit methodology for mines further
refinements may arise from conducting energy audits which
may lead to the identification of additional improvements. It is
recommended that future development of methods for data
reconciliation has to be done.